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The age and growth of the white sturgeon (Acipenser transmontanus richardson) of the Fraser River, British… Semakula, Saul Nelson 1963

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THE AGE AND GROWTH OF THE WHITE STURGEON (ACIPENSER TRANSMONTANUS RICHARDSON) OF THE FRASER RIVER, BRITISH COLUMBIA, CANADA  by SAUL NELSON SEMAKULA B.Sc.  ( L o n d o n ) , The U n i v e r s i t y C o l l e g e of East A f r i c a , 1959  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF M a s t e r of in  Science  the  Department of  We a c c e p t t h i s t h e s i s as standard  Zoology  c o n f o r m i n g t o the  THE UNIVERSITY OF BRITISH COLUMBIA OCTOBER,  1963  requir  In presenting t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e for reference and study.  I further agree that permission for  extensive copying of the t h e s i s for s c h o l a r l y purposes may be granted by the Head of my Department or by h i s  representatives.  I t i s understood that copying or P u b l i c a t i o n of t h i s t h e s i s for f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission.  Department of Zoology The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, B r i t i s h Columbia Canada  i  ABSTRACT  Between May 1 and October 28, 1962, growth data were obtained from 255 specimens of white sturgeon (Acipenser transmontanus,  Richardson) from the Fraser R i v e r , B r i t i s h  Columbia, Canada.  Most of the specimens measuring 36" and over  i n length were those caught i n c i d e n t a l l y i n the salmon fishermen's nets i n the lower part, of the Fraser River as far upstream as Langley, B r i t i s h Columbia.  Specimens.smaller than  t h i s length were g i l l - n e t t e d at Dewdney Slough near M i s s i o n C i t y , B r i t i s h Columbia. Age was determined f o r 230 specimens from sections of the f i r s t p e c t o r a l f i n r a y s . the m a t e r i a l s were unreadable.  Sections from the r e s t of Growth i n length was studied  by averaging observed length at capture and r e l a t i n g these to age, and a l s o by b a c k - c a l c u l a t i n g growth at the d i f f e r e n t ages of the f i s h ' s l i f e .  Growth i n weight was studied by averaging  the observed weights at times of capture and r e l a t i n g these to age and a l s o by c a l c u l a t i n g weights at d i f f e r e n t the length-weight r e l a t i o n s h i p .  lengths u s i n g  From the study of growth i n  length i t was revealed that growth i n both sexes i s s i m i l a r up to age twenty, but a f t e r that age the females grow f a s t e r than the males. sexes grows  I t was a l s o revealed that n e i t h e r of the  to a f i x e d maximum length.  Study of growth i n  ii weight revealed a s i m i l a r pattern u n t i l the f i s h reached 30", but a f t e r  that length the females had an advantage over the  males. An attempt was made t o determine the age at spawning maturity by r e l a t i n g cessation of growth to the maturation of the gonads.  I t was found that some males s t a r t spawning at  age e l e v e n , but females may not spawn u n t i l they reach age twenty-five t o twenty-seven.  Periods between spawnings are  v a r i a b l e i n the d i f f e r e n t i n d i v i d u a l s , but may range from f i v e t o ten years. A study of the m o r t a l i t y r a t e s i n the Fraser River white sturgeon revealed that the present f i s h i n g m o r t a l i t y rate i s excessive.  As a r e s u l t the f i s h e r y i s now u t i l i s i n g  fish  from the young age groups, which may lead to the d e p l e t i o n of stocks.  Due t o the i n c i d e n t a l nature of the f i s h e r y i t i s not  pr a c t i c a l l y p o s s i b l e to introduce measures which would effect a reduction i n the f i s h i n g m o r t a l i t y .  I t i s suggested there be  introduced measures which would protect the spawning s t o c k s . These include i n t r o d u c t i o n of a 54" maximum s i z e - l i m i t beyond which length no sturgeon may be taken, complete p r o h i b i t i o n of the s e t - l i n e f i s h e r y , and p r o h i b i t i o n of sturgeon f i s h i n g on the Fraser i n the area between Langley and Y a l e ,  B r i t i s h Columbia.  viii  ACKNOWLEDGEMENT  I wish Pakcers  t o e x p r e s s tny s i n c e r e t h a n k s  L t d . f o r a l l o w i n g me t o h a n d l e  collection  My u n l i m i t e d  I  thanks  the analysis  offering  critically  sturgeon  fishery  valuable stimulation  reading the manuscript; for their  throughout  t h e s t u d y , and f o r  and D r s . N. J . W i l i m o v s k y and  C.  C. L i n d s e y s u p e r v i s e d t h e e a r l i e r  criticisms  v a l u a b l e a d v i c e on t h e f i e l d  on t h e m a n u s c r i p t . stages of t h i s work.  Dr.  s t u d y and  My t h a n k s  t o many f r i e n d s who have h e l p e d me i n f i e l d  other  f o r h i s guidance  t o t h e f o l l o w i n g p e o p l e ; D r . W. A. Clemens  G. N o r t h c o t e  due  from  on t h e F r a s e r R i v e r .  a r e due t o D r . P. A. L a r k i n  T.  offered  during the  o f t h e d a t a , and p r e p a r a t i o n o f t h e m a n u s c r i p t .  am v e r y g r a t e f u l  for  fish  o f m a t e r i a l s , and f o r t h e i n f o r m a t i o n o b t a i n e d  them r e g a r d i n g t h e w h i t e  in  their  t o t h e Westminster  are also  and i n many  ways. I would a l s o  Universities  Foundation  like  t o extend  my t h a n k s  t o the Canadian  u n d e r whose a u s p i c e s I was awarded a  commonwealth s c h o l a r s h i p w h i c h e n a b l e d me t o u n d e r t a k e  this  study.  iii TABLE OF CONTENTS  ABSTRACT  i  INTRODUCTION..  1  MATERIALS AND METHODS  6  1)  Measurements  6  a) b)  6 .6  t o t a l length. fork length  2)  Weight  6  3)  Sex  7  4)  Stomach Contents  7  5)  F i n Rays  7  Age Determination of the Fraser River White Sturgeon  8  Sources of E r r o r i n Age Determinations  11  Growth of the Fraser R i v e r White Sturgeon  13  1)  Growth i n length.  2)  Method I Method I I Growth of the d i f f e r e n t year c l a s s e s  3)  13 .........13 13 ...19  R e l a t i o n s h i p between s i z e and growth of the d i f f e r e n t year classes  Growth i n Weight of the Fraser River White Sturgeon  19 20  Age at F i r s t Spawning and I n t e r v a l s Between Spawnings.... 20 M o r t a l i t y Rates i n the Fraser R i v e r White Sturgeon  21  T h e o r e t i c a l Y i e l d at D i f f e r e n t Rates of Natural and F i s h i n g M o r t a l i t y Rates  22  )  .  RESULTS.  24  Age D e t e r m i n a t i o n .  ,  24  Growth of the F r a s e r R i v e r White Sturgeon 1)  24  Growth i n l e n g t h  ..24  Growth of the d i f f e r e n t year c l a s s e s R e l a t i o n s h i p between s i z e and growth o f d i f f e r e n t year c l a s s e s 2)  the  Growth i n w e i g h t Length/weight  .....40 45  relationship.....  Age at F i r s t Spawning and I n t e r v a l s  33  .49  Between S p a w n i n g s . . . . 54  M o r t a l i t y Rates i n the F r a s e r R i v e r White Sturgeon  57  T h e o r e t i c a l Y i e l d at D i f f e r e n t Rates of N a t u r a l and F i s h i n g M o r t a l i t y Rates  60  The Food of t h e F r a s e r R i v e r White Sturgeon DISCUSSION  ...64 v  MANAGEMENT  .67 .74  SUGGESTIONS FOR FUTURE MANAGEMENT.  78  SUMMARY  81  LITERATURE CITED  85  APPENDIX I .  88  A n a l y s i s of Stomach Contents  APPENDIX I I . T h e o r e t i c a l Y i e l d Computations  94  V  LIST OF TABLES  Table I  L e n g t h and age of the male and female s t u r g e o n of the F r a s e r R i v e r , May 1 t o October 28, 1 9 6 2 . . . . . . 2 5 26  Table I I  Average e m p i r i c a l l e n g t h at time of c a p t u r e f o r the male and female w h i t e s t u r g e o n of the F r a s e r R i v e r , May 1 t o October 28, 1962 ,30  Table I I I  Back c a l c u l a t e d l e n g t h s f o r t h e female s t u r g e o n of the F r a s e r R i v e r m a t e r i a l c o l l e c t e d between May 1 and October 28, 1 9 6 2 . . . . ....34  T a b l e IV  Back c a l c u l a t e d l e n g t h s f o r t h e male s t u r g e o n of t h e F r a s e r R i v e r - - m a t e r i a l c o l l e c t e d between May 1 and October 28, 1962 ...35  Table V  Average e m p i r i c a l weight f o r t h e male and female s t u r g e o n of the F r a s e r R i v e r , May 1 t o October 28, 1962 46  Table V I  Comparison between average e m p i r i c a l w e i g h t s and c a l c u l a t e d w e i g h t s f o r the male and female w h i t e s t u r g e o n on t h e F r a s e r R i v e r , May 1 t o October 28, 1962 ...50  Table V I I  Age at f i r s t spawning and subsequent spawnings i n the F r a s e r R i v e r male w h i t e s t u r g e o n  Table V I I I T a b l e IX  Age a t f i r s t spawning and subsequent i n the F r a s e r R i v e r w h i t e s t u r g e o n . .  .55  spawnings  Y i e l d at d i f f e r e n t l e v e l s of f i s h i n g and n a t u r a l m o r t a l i t y r ^ i n g R i c k e r ' s method of e s t i m a t i n g e q u i l i b r i u m y i e l d ( y i e l d i n u n i t s of weight)  55  .63  vi ILLUSTRATIONS  Fig. 1  The r e l a t i o n s h i p between fork length and r a d i a l length of the f i n ray s e c t i o n (along s t r a i g h t line)  15  Fig. 2  The r e l a t i o n s h i p between fork length and r a d i a l length of the f i n ray s e c t i o n (along curved  Fig. 3  Age d i s t r i b u t i o n i n the Fraser River white sturgeon commercial catches  27  Length frequency d i s t r i b u t i o n of the Fraser R i v e r white sturgeon  28  Fig. 4 Fig. 5  Growth i n length of the Fraser River male white sturgeon (average e m p i r i c a l fork length by age groups  Fig. 6  Growth i n length of the Fraser River female white sturgeon (average e m p i r i c a l fork lengths by 3LQQ ^jtTOUpS ^ 0 0 0 « a 0 0 e 0 « e 0 * 0 « « * e 9 0 O 0 O 0 0 O 0 B * 0 O O  o o * 3 2  Fig. 7  Growth i n length of the female Fraser R i v e r white sturgeon (average c a l c u l a t e d fork lengths by age groups) ....36  Fig. 8  Growth i n length of the male Fraser R i v e r white sturgeon (average c a l c u l a t e d fork length by age groups)  Fig. 9  Walford transformation of c a l c u l a t e d lengths of the Fraser R i v e r male white sturgeon  37 ..38  F i g . 10  Walford transformation of c a l c u l a t e d lengths of the Fraser River female white sturgeon .39  F i g . 11  C a l c u l a t e d growth h i s t o r i e s of the year classes of the female Fraser River white sturgeon .41  F i g . 12  C a l c u l a t e d growth h i s t o r i e s of the year classes of the male Fraser R i v e r white s t u r g e o n . . . .42  F i g . 13  R e l a t i o n s h i p between s i z e and growth of the d i f f e r e n t female year  F i g . 14  R e l a t i o n s h i p between s i z e and growth of d i f f e r e n t male year c l a s s e s . . . . . . . . . . . . . . . . . . . . . . 4 4  vii Fig.  15  Growth i n weight of the Fraser R i v e r male white sturgeon (average weight by age groups) ..... A » i v . . . ».,.... •. .47  Fig.  16  Growth i n weight of the F r a s e r R i v e r female white sturgeon (average weight by age groups) .... 48  Fig.  17  Length/weight r e l a t i o n s h i p f o r the F r a s e r R i v e r white sturgeon.  ..  51  Fig.  18  Growth i n weight of the F r a s e r R i v e r white sturgeon, c a l c u l a t e d weights a t d i f f e r e n t lengths..........*...«.............. 52  Fig.  19  Growth i n weight o f the F r a s e r R i v e r white sturgeon, c a l c u l a t e d Weights a t d i f f e r e n t ages ...................... 53  Fig.  20  Catch curve f o r the F r a s e r R i v e r white s t u r g e o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58  Fig. Fig.  21 22  Y i e l d i n weight a t d i f f e r e n t r a t e s of f i s h i n g and n a t u r a l m o r t a l i t y , , , . . . .  61  Y i e l d at f i x e d f i s h i n g but v a r l a b 1 n a t u r a l m o r t a l i t y . . . . . .x 62  PLATES  Plate 1  Cross s e c t i o n of the f i r s t p e c t o r a l f i n r a y o f the F r a s e r R i v e r white sturgeon showing the c o n s e c u t i v e zones used i n d e t e r m i n i n g age..10  PUte  2  A c r o s s s e c t i o n o f the f i r s t p e c t o r a l f i n ray of t h e F r a s e r R i v e r white sturgeon showing r a d i c a l axes a l o n g which measurements f o r bake c a l c u l a t i o n were taken, 14  Plate 3  A nomograph used i n back c a l c u l a t i o n of l e n g t h o f the F r a s e r R i v e r white sturgeon..18  INTRODUCTION  In a l l areas where c o m m e r c i a l l y e x p l o i t e d  sturgeons  ( A c i p e n s e r i d a e ) have been s t u d i e d , t h e r e has been g r e a t d e p l e t i o n of s t o c k s and i n some p l a c e s v i r t u a l e x t i n c t i o n (Goode et a l . 1886, Tower 1909, Sunde 1961, and Harkness and Dymond 1961). T h i s d e p l e t i o n has a r i s e n from two main c a u s e s .  In  t h e f i r s t p l a c e t h e economic importance of t h e s t u r g e o n i n the e a r l y 1800*8 was n o n - e x i s t e n t and because of the damage t h e y d i d t o t h e f i s h e r m e n ' s n e t s and the s u p p o s i t i o n t h a t t h e y f e d on the spawn of more e c o n o m i c a l l y i m p o r t a n t s p e c i e s , a t t e m p t s were made t o e r a d i c a t e them.  S e c o n d l y , when t h e economic p o t e n t i a l of the  s t u r g e o n was r e c o g n i s e d , they were h e a v i l y f i s h e d .  Ignorance of  t h e b i o l o g y of the s t u r g e o n r e s u l t e d i n an i r r a t i o n a l  utilization  of t h e s t o c k s w h i c h i n t u r n l e d t o t h e i r d e p l e t i o n . E a r l y a c c o u n t s of t h e s t u r g e o n show t h a t s t u r g e o n were f o r m e r l y v e r y abundant i n N o r t h American w a t e r s .  Goode et a l .  (1886) s t a t e d t h a t i n Green Bay, W i s c s o n i n , f i s h e r m e n o f t e n t o o k a hundred o r more s t u r g e o n i n t h e i r pound n e t s , but s i n c e t h e y were f i s h i n g f o r w h i t e f i s h t h e y r e g a r d e d the s t u r g e o n a n u i s a n c e and an annoyance.  A few f i s h e r m e n were c o n s i d e r a t e enough t o  lower the c o r n e r of a net and a l l o w t h e s t u r g e o n t o e s c a p e , but most drew them out w i t h a g a f f - h o o k and r e l e a s e d  them wounded,  . . o r took them ashore and threw them on a r e f u s e heap,  2  asserting  t h a t t h e r e would be so many l e s s t o t r o u b l e them i n f u t u r e . Stone (1900) r e f e r s  t o the r e c k l e s s  i n M i s s i q u o i R i v e r , New Y o r k .  s p e a r i n g of t h e  sturgeon  The eggs from t h e speared  s t u r g e o n s c o v e r e d the b r i d g e and s p e a r i n g had t o be s t o p p e d , t o p r o t e c t the s t u r g e o n but t o a v o i d the s t e n c h .  not  Phyca (1956)  mentions t h a t the s t u r g e o n were once abundant enough i n C a l i f o r n i a w a t e r s t o have been c o n s i d e r e d a n u i s a n c e . The g r e a t d i s r e g a r d f o r t h e s t u r g e o n seems t o have, a r i s e n from the f a c t  t h a t people i n t h o s e days d i d not know how  t o cook them, and c o n s i d e r e d s t u r g e o n a food f o r " i n f e r i o r p e o p l e " . Lack o f knowledge on t h e f e e d i n g b e h a v i o u r of t h e s t u r g e o n  led  t o statements such as t h a t of P r i n c e (1899) where he r e f e r r e d  to  i t as " t h e most v o r a c i o u s of a l l the f i s h - e a t i n g s p e c i e s " and s u g g e s t i n g t h a t " i t s c o u r s t h e spawning grounds of t h e g r e a t l a k e t r o u t , the w h i t e f i s h and e v e r y o t h e r k i n d of market f i s h ,  valuable  s u c k i n g up the eggs w i t h i t s t u b e - l i k e mouth and  s c o o p i n g i n whole s c h o o l s of d e f e n s e l e s s f r y " .  These  encouraged t h e wanton d e s t r u c t i o n of s t u r g e o n s t o c k s  "rumours" i n favour  of t h e o t h e r s p e c i e s . W i t h t h e b e g i n n i n g of smoke c u r i n g and t h e use of s t u r g e o n roe f o r making c a v i a r , the c o m m e r c i a l e x p l o i t a t i o n of t h e s t u r g e o n began and by 1880 i t had become an i m p o r t a n t branch o f t h e f i s h i n g i n d u s t r y (Harkness and Dymond, 1961).  S i n c e the  b e g i n n i n g of t h e commercial e x p l o i t a t i o n of the s t u r g e o n has been such r a p i d and u n i v e r s a l d e p l e t i o n of s t o c k s  there  that a l l  t h e i m p o r t a n t f i s h e r i e s have been c l o s e d down a t one time o r another.  3 Smith (1914) hinted at the d e c l i n e of stocks on the A t l a n t i c coast, the P a c i f i c coast, the Great Lakes and the Lake of the Woods, and s t a t e d that the s i t u a t i o n demanded an absolute p r o h i b i t i o n of capture or sale of sturgeon for a long term of years  not less than ten y e a r s .  Carlander (1947) documented  the d e c l i n e of lake sturgeon i n the Lake of the Woods from 1888 t o 1947, w h i l e Harkness and Dymond (1961) and Sunde (1961) have discussed various f i s h e r i e s i n eastern Canada and Manitoba. Bajkov (1949) presented several curves showing the  sturgeon  d e c l i n e i n Chesapeake Bay, Lake of the Woods, Lake Michigan, and the Columbia R i v e r . These  p e c u l i a r i t i e s i n the sturgeon f i s h e r y have  prompted i n v e s t i g a t i o n s i n t o i t s biology to which s e v e r a l workers have made v a r y i n g c o n t r i b u t i o n s .  Harkness (1923) studied the r a t e  of growth and food of the lake sturgeon (Acipenser rubicundus Le Sueur = A ^ fulvescens)  i n Lake Nipigon, and Probost and Cooper  (1954) studied the age, growth and reproduction of Acipenser fulvescens Rafinesique i n the Lake Winnebago r e g i o n , Wisconsin. Bajkov and Neave (1930) studied the biology of the lake sturgeon (Acipenser fulvescens) i n Lake Winnipeg, Manitoba, and presented data on the spawning h a b i t s , food and growth, as w e l l as suggesti n g some measures of conservation. C u e r r i e r and Roussow (1951) studied age and growth of the lake sturgeon from Lake S t . F r a n c i s , and S t . Lawrence R i v e r , Quebec, w h i l e C u e r r i e r (1951) reviewed the l i t e r a t u r e on age determination i n the sturgeon and o u t l i n e d the p e c t o r a l f i n - r a y technique.  Schneberger and Woodbury (1944) studied the lake  4 sturgeon of Winnebago Lake, Wisconsin,  and Bajkov (1949, 1951),  Phyca (1956) and Chadwick (1959) studied the growth and migration of the white sturgeon on the Columbia and Sacramento R i v e r s . Roussow (1957) considered the spawning p e r i o d i c i t y i n the sturgeon of northern Quebec and r e l a t e d h i s findings to h i s previous studies i n Lakes S t . Louis and S t . F r a n c i s , the S t . Lawrence R i v e r , the Danube and Dneister of Romania, and the U r a l and Volga R i v e r s . Sunde (1961) studied growth and reproduction of the lake sturgeon (Acipenser fulvescens) i n NelsOn R i V e r , Manitoba.  He considered  the effect of f i s h i n g on the sturgeon p o p u l a t i o n s , and made some recommendations for future management.  Harkness and Dymond  (1961) reviewed the l i t e r a t u r e On the lake sturgeon and compiled information accumulated between 1922 and i960 from Lakes Nipigon, N i p i s s i n g and E r i e . In Europe, reference i s made to the work of Derjavin (1922) on the s t e l l e t e d sturgeon (Acipenser s t e l l a t u s  (Pallas)),  and Holzmayer (1924) on the growth of Acipenseridae.  Kuzmin  (1954) studied the s t r u c t u r a l and developmental changes i n the testes and ovaries of j u v e n i l e sturgeon (Acipenser guldenstadti B r a n d t ) , i n R u s s i a , ChugnoV (1925) and Classen (1944) studied the age and growth of the sturgeon while s e v e r a l other workers ( p a r t i c u l a r l y i n Russia) have treated various aspects of the biology of the  sturgeon.  Before 1880, the white sturgeon f i s h e r y On the Fraser R i v e r i n B r i t i s h Columbia was only a subsistance occupation of the Indians*  Lord (1886) mentioned of a trade i n a rough kind  of i s i n g l a s s (a form Of g e l a t i n made from the l i n i n g of the a i r  5 bladder of the sturgeon) that e x i s t e d between the Indians and the Hudson Bay Company, but t h i s trade had ceased by 1866.  On the  F r a s e r , as i n many other sturgeon waters of North America, the white sturgeon was not economically important In those days. When markets for c a v i a r and smoked sturgeon opened up i n the United S t a t e s , commercial f i s h i n g began.  By 1897 sturgeon f i s h i n g  had become an important part of the f i s h i n g industry and offered w i n t e r employment to a large number of resident fishermen (the value of the landings was over $50,000.00 (Commission of Conservation, Canada, 1911). The sturgeon f i s h i n g industry was so remunerative at i t s s t a r t that a large  body of fishermen  engaged i n i t .  Peak  production on the Fraser seems to have occurred a f t e r  1897 but  w i t h i n three years the catch had f a l l e n to 207 of the  initial  o  catch and by 1905 i t had been reduced by 93.37 . 0  The d e c l i n e i n  the sturgeon stocks was so pronounced by 1911 that some p r o t e c t i v e measures were taken.  Only g i l l - n e t s and d r i f t n e t s of 12" mesh T  were allowed and a closed season was declared from November 15 to March 25.  The s i z e l i m i t , however, was only 8" or three pounds.  Catches continued to d e c l i n e and although the s i z e l i m i t has been r e v i s e d , the f i s h e r y has s t i l l not been r e v i v e d .  The present s i z e  r e g u l a t i o n s allow fishermen to r e t a i n only those f i s h that have a t t a i n e d 36" i n t o t a l length.  Present catches range between  20,000 to 30,000 pounds per annum (BC Catch S t a t i s t i c s ) . The present study i s an attempt to determine age and growth i n the Fraser River white sturgeon and to show how the f i n d i n g s can be u t i l i s e d i n a c h i e v i n g a maximum sustained y i e l d .  6  MATERIALS AND METHODS  Most of the m a t e r i a l s for t h i s study were c o l l e c t e d from the f i s h docks of Westminster Packers L t d . , New Westminster where c o l l e c t o r boats b r i n g i n f i s h from the lower part of the Fraser River as far upstream as Langley.  Sturgeons landed were  those caught i n c i d e n t a l l y i n salmon nets and i n most cases conformed to the l e g a l length of 36".  Specimens smaller than  36" ( t o t a l length) were g i l l - n e t t e d at Dewdney Slough near Mission C i t y , by the author. When landed, each f i s h was assigned a s e r i a l number and the f o l l o w i n g data taken: 1.  Measurements a)  Total length.  Length from the t i p of the nose  to the t i p of the t a i l , w i t h the t a i l drawn to the tape. b)  Fork l e n g t h .  Length from the t i p of the nose  t o the fork of the t a i l w i t h the t a i l spread out. A l l measurements were taken with a s t e e l tape and the length was measured to nearest one-quarter  2.  inch.  Weight Most of the f i s h were weighed w i t h a C h a t i l l o n s p r i n g  balance of thirty-pound c a p a c i t y , c a l i b r a t e d i n one quarter pounds.  A Larger scale balance was used for bigger specimens and a d i e t a r y scale for very small specimens. were f o r undressed 3.  The recorded weights  fish.  Sex The f i s h were opened and sex determined by v i s u a l  examination of the gonads.  i n some small specimens i t was  necessary to use a microscope to determine the sex. of maturity of the f i s h was a l s o observed.  The state  F i s h showing  u n d i f f e r e n t i a t e d gonads were recorded as "young" while those showing r i p e eggs were recorded as " r i p e " , and those w i t h d i f f e r e n t i a t e d gonads, but no r i p e eggs were recorded as "mature". Specimens that looked to have spawned r e c e n t l y were recorded as "spawned". 4.  Stomach contents Stomachs from n i n e t y - s i x sturgeons were c o l l e c t e d and  preserved i n a d i l u t e s o l u t i o n of f o r m a l i n .  Each stomach was  l a b e l l e d w i t h the s e r i a l number assigned to the f i s h , examined i n the l a b o r a t o r y . f u l l of p u t r i f y i n g eulachons.  and l a t e r  Specimens taken i n e a r l y May were These were cut open on the spot  and i d e n t i f i c a t i o n of the contents, as far as p o s s i b l e , was made by eye. 5i  F i n rays For each f i s h a f i r s t p e c t o r a l f i n r a y , and i n some  cases both f i r s t p e c t o r a l f i n r a y s , were c o l l e c t e d by c u t t i n g them o f f the f i s h at the point of a r t i c u l a t i o n with the p e c t o r a l girdle.  These were l a b e l l e d w i t h a paper tag c a r r y i n g the s e r i a l  number of the f i s h , which was t i e d to the f i n ray by a brass wire passed through the blood v e s s e l that runs through the centre  8 o f the f i n r a y ' s b a s e .  The f i n r a y s were t h e n d r i e d i n t h e sun  and l a t e r used f o r age d e t e r m i n a t i o n .  Age d e t e r m i n a t i o n o f the F r a s e r R i v e r w h i t e s t u r g e o n S e v e r a l methods are a v a i l a b l e f o r d e t e r m i n i n g t h e age of f i s h .  These i n c l u d e t h e use of s c a l e s , o t o l i t h s , o p e r c u l a r  bones, c l a v i c u l a r bones, v e r t e b r a e , f i n r a y s , distribution, etc. for a l l  length-frequency  Not a l l these methods, h o w e v e r , a r e s u i t a b l e  species. In t h e s t u r g e o n , s e v e r a l w o r k e r s have a p p l i e d  d i f f e r e n t techniques w i t h v a r y i n g success.  The s c a l e t e c h n i q u e ,  w h i c h has been used s u c c e s s f u l l y i n many o t h e r f i s h e s ,  does not  a p p l y f o r the s t u r g e o n because t h e s e f i s h do not p o s s e s s s c a l e s . S e v e r a l w o r k e r s , n o t a b l y D'Ancona ( 1 9 2 4 ) , have used t h e s c u t e s found on t h e back and s i d e s of s t u r g e o n f o r d e t e r m i n i n g age. T h i s method i s u n s u c c e s s f u l because the s c u t e s degenerate as f i s h grow o l d e r and i n v e r y o l d f i s h they d i s a p p e a r completely.  the  almost  Harkness (1923) used t h e o t o l i t h s t o age t h e l a k e  s t u r g e o n ( A c i p e n s e r r u b i c u n d u s ) , but p o i n t e d out t h a t o t o l i t h s from l a r g e r f i s h were v e r y t h i c k and the r i n g s were o f t e n indistinct.  S e v e r a l other workers i n North America (Bajkov  1930, Schneberger and Woodbury 1944), have used o t o l i t h s s u c c e s s f u l l y i n aging sturgeon.  However, C u e r r i e r (1951) r e p o r t s  t h a t he d i d not f i n d t h e method s a t i s f a c t o r y  i n h i s study of the  lake sturgeon (Acipenser f u l v e s c e n s ) . In 1932, D e r j a v i n ( c i t e d i n C u e r r i e r (1951) made age d e t e r m i n a t i o n s on the S u v r i u g a ( A c i p e n s e r s t e l l a t u s )  from  9 c l e i t h r a l bones.  C u e r r i e r (L95L) reports that the c l e i t h r u m  could not be used i n S t . Lawrence River sturgeon because they showed large c a v i t i e s i n the centres. extensively.  F i n rays have been used  Apparently the f i r s t published work u s i n g f i n rays  i n sturgeon was that of Kleer i n 1916 ( C u e r r i e r 1951). America t h i s method has been used  In North  Bajkov (1949), C u e r r i e r  (1951), Probost and Cooper (1954), Phyca (1956), Roussow (1957) and Sunde (1961).  I f a transverse s e c t i o n of the f i r s t f i n ray  i s c u t , i t shows successive l i g h t and dark zones.  These are  i n t e r p r e t e d as i n d i c a t i n g the pronounced difference i n r a t e of growth between winter and summer p e r i o d s .  The v a l i d i t y of these  zones to i n d i c a t e age i s s t i l l under observation.  However, the  work of Holzmayer c i t e d i n C u r r i e r (1951) showed that the number of zones i n the f i n ray taken from a f i s h of known age corresponded w i t h the age of the f i s h ,  Probost and Cooper (1954)  have provided further supporting evidence from the lengthfrequency d i s t r i b u t i o n .  They found that there was agreement  between the modes of the length-frequency d i s t r i b u t i o n of a l l f i s h i n t h e i r samples with the modal length of f i s h of assigned age groups. The age of the Fraser River white sturgeon was determined from transverse sections of the f i r s t p e c t o r a l f i n r a y . As most of the specimens were taken from commercial catches t h i s was the only part which could be c o l l e c t e d from the  fish  without rendering i t less acceptable to market.  Thoroughly d r i e d  f i n rays were sectioned u s i n g a two-bladed saw.  A transverse  s e c t i o n was taken a short distance from the base of the f i n r a y . A double-bladed saw was favoured because i t gave sections of uniform s i z e , and the blades could be set so that sections between  10 0.3 t o 0.5 mm were obtained.  The sections were mounted i n pure  g l y c e r i n e and the age determined, using a b i n o c u l a r microscope and transmitted l i g h t , by counting the number of consecutive zones on the s e c t i o n .  In most cases i t was not necessary t o p o l i s h the  s e c t i o n s , but i n some, p a r t i c u l a r l y i n the older ones, p o l i s h i n g was necessary i n order t o make the zones more v i s i b l e . was done w i t h a No. 0 grade sand paper.  This  P l a t e 1 shows a cross-  s e c t i o n of a f i r s t p e c t o r a l f i n ray.  Plate 1  Cross s e c t i o n of the f i r s t p e c t o r a l f i n r a y of the Fraser River white sturgeon showing consecutive zones used i n determining age  11 Sunde (1961) reported the loss of a n n u l i when the s e c t i o n i s taken at a distance from the base of the f i n r a y .  It  was thus necessary to s e l e c t a region where a consistent number of r i n g s could be obtained.  This was done by t a k i n g s e r i a l  sections at i n t e r v a l s from the base of the f i n ray and counting the zones i n each s e c t i o n .  In b i g fishes the i n t e r v a l s were at  one quarter of an i n c h , but t h i s was r e l a t i v e l y reduced i n fishes smaller than 20"-. taken  It was observed that most of the sections  from the f i n ray base were d i f f i c u l t  to read.  This  area coincides w i t h the notched part of the f i n ray where zones tend to fuse.  Sections taken %" from the f i n ray base were,  except i n one.case, readable.  Sections taken 3/4" from the f i n  ray base showed some loss of a n n u l i .  Therefore a l l sections  used i n t h i s study were taken %" from the base of the f i n r a y .  Sources of e r r o r i n age determination The s t r u c t u r e of the f i n ray i s g r e a t l y influenced by the pattern of growth of the f i s h .  Environmental factors  like  temperature, changes i n the water l e v e l , and other factors such as spawning, i l l n e s s , damage to the f i n s during m i g r a t i o n , presumably a l l lea\emarks on f i n s which tend to obscure the winter and summer zones.  Therefore, one source of e r r o r i n age  determination a r i s e s from the s t r u c t u r e of the f i n i t s e l f .  Some  sections may show great e r o s i o n , p a r t i c u l a r l y i n the centre of the s e c t i o n tending to "push" the f i r s t readable r i n g a great distance from the c e n t r e .  This leads to underestimation of age  and erroneous estimate of growth r a t e i n the f i r s t year. sections scars e v i d e n t l y due to i n j u r y  may upset the  In some  12 arrangement of the zones and thereby introduce e r r o r s i n age determination. Quite often the second f i n ray grows i n t o the f i r s t and confuses the arrangement of zones.  This may r e s u l t i n some  fusion of r i n g s or other complications which make age determination d i f f i c u l t .  It has a l s o been observed that some r i n g s tend  t o s p l i t i n t o two on one side of the s e c t i o n , thus making i t difficult  to decide whether to take them as two fused r i n g s or  one r i n g . Another source of e r r o r i s the region from which the s e c t i o n i s taken as explained e a r l i e r .  I f the s e c t i o n i s taken  too near the base of the f i n ray there i s a danger of underestimating the age of the f i s h due t o the tendency of the r i n g s to fuse.  I f the s e c t i o n i s taken too f a r from the base the age  w i l l be underestimated due to loss of r i n g s . A l l of these e r r o r s can be minimised by being c o n s i s t e n t i n the s e c t i o n i n g procedure and r i n g r e a d i n g . A l l the sections were taken from a distance of %" from the base of the f i n ray i n a l l b i g specimens (over 20") and at the same r e l a t i v e distance i n the smaller ones.  In a l l sections w i t h  eroded c e n t r e s , where a loss of a r i n g was suspected, one r i n g was added to the count. counted as a s i n g l e r i n g .  A l l r i n g s which seemed to s p l i t were  13 Growth of the F r a s e r R i v e r white sturgeon 1.  Growth i n l e n g t h Growth i n l e n g t h of the F r a s e r R i v e r white sturgeon 1)  s t u d i e d by two methods: age,  and  2)  to  by back c a l c u l a t i o n .  Method 1.  Mean f o r k l e n g t h of each age  ( s e p a r a t i n g sexes) was 5,  by r e l a t i n g the l e n g t h at capture  was  c a l c u l a t e d and  group  p l o t t e d a g a i n s t age  (Figs.  6).  Method 2 .  (Back c a l c u l a t i o n method)  The  study of  growth i n l e n g t h of the F r a s e r R i v e r white sturgeon by method of back c a l c u l a t i o n was ray.  Before  done from s e c t i o n s of the  t h i s c o u l d be done, i t was  first  pectoral f i n  necessary t o study  r e l a t i o n s h i p between the growth i n l e n g t h of the f i s h and growth of the f i n ray. of the f i r s t  For t h i s study, c l e a r l y v i s i b l e  p e c t o r a l f i n r a y of f i s h whose age  determined w i t h c o n f i d e n c e , many s c a r s , and  were s e l e c t e d .  Sections  the  sections  been that showed  s e c t i o n s that showed i n c u r s i o n of the second f i n  r a y i n t o the f i r s t were avoided. mounted i n pure glycerene sheet  had  the  and  Each of these s e c t i o n s  i t s image p r o j e c t e d on a white  of paper u s i n g a s c a l e p r o j e c t o r at medium power.  o u t l i n e of the image was  t r a c e d on the paper and  marked o f f at i t s p o i n t of c u r v a t u r e . images were taken.  One  was  was  Two  An  each r i n g  was  measurements of  the  the length of a l i n e running  from  the c e n t r e of the f i n r a y j o i n i n g the marked o f f r i n g s t o the periphery  of the s e c t i o n .  sinuous l i n e .  The  In most cases t h i s was  second measurement was  a curved  or  a s t r a i g h t l i n e from  14 the centre of the s e c t i o n to the same point on the periphery. map  measurer was used to f i n d the length of these two  These two l i n e s are demonstrated i n P l a t e 2 and w i l l  A  lines. henceforth  be r e f e r r e d to as r a d i a l measurements.  Plate 2  A cross s e c t i o n of the f i r s t p e c t o r a l f i n ray of the Fraser River white sturgeon showing r a d i a l axes along which measurements f o r back c a l c u l a t i o n were taken  To obtain the r e l a t i o n s h i p between growth i n length of the f i s h and growth of the f i r s t p e c t o r a l f i n ray, the fork length of the f i s h was p l o t t e d against the s t r a i g h t and curved r a d i a l measurements of the f i n ray sections ( F i g s .  1,  2>  Fig  L The relationship the f i n  ray  between fork length section  and  (along straight  radial line )  length of  16  90  80  70 cn ui o 60  50 x i— o z UJ  401  o  on  o  u-  o o  o  e> o/6 o OOOyo o 0 _ o / ooo 0 O BO O OO 0 o o / o a oo o Xoo8 o o/°o o  JO  o o  0„ 0  20  10  I  2  3  4  5  RADIAL L E N G T H Fig 2  The  relationship between fin  ray  fnrk  OF  6 FIN  7 RAY  Ur.gth and  section  8  SECTION radial  length  ( a l o n g c u r v e d line )•  of  17..  I t w i l l be noticed that although there i s a c e r t a i n amount of s c a t t e r of p o i n t s , a l i n e a r r e l a t i o n s h i p i s suggested i n both cases.  Regression  method of l e a s t squares. Y = 0.9 > Y =-3.1  9.5x  .t 10.2x  l i n e s were f i t t e d on these using the The'equations obtained are:; . (along curve)  ...1  (along s t r a i g h t l i n e )  ...2.  T h i s , t h e r e f o r e , showed that.there was a r e l a t i o n s h i p between : growth i n length of the f i s h and growth of the f i r s t p e c t o r a l f i n ray.  These equations could be used f o r back c a l c u l a t i n g growth  at d i f f e r e n t years, s u b s t i t u t i n g a measured length between r i n g s , f o r x.  These two r e l a t i o n s h i p s had.the same c o r r e l a t i o n co-  e f f i c i e n t =0.89, but measurements taken along the curved  line  showed a smaller standard d e v i a t i o n from the r e g r e s s i o n l i n e . I t was therefore decided to use equation 1.for back c a l c u l a t i o n . For back c a l c u l a t i n g length at d i f f e r e n t years, the distances between marked-off r i n g s were measured. these were, so c l o s e together that i t was  In many cases  d i f f i c u l t to obtain >  accurate measurements without f u r t h e r m a g n i f i c a t i o n .  This  d i f f i c u l t y was. overcome by p r o j e c t i n g the image.on a white cardboard using an epidiascope which magnified the image two t o four times without d i s t o r t i o n . then measured w i t h a map  The distances between the r i n g s were measurer-.  A. nomograph was made t o speed up the c a l c u l a t i o n .  This  c o n s i s t e d of a hard cardboard which had.a f i x e d s c a l e representing the length of the f i s h , and a movable scale r e p r e s e n t i n g the r a d i a l measurements of the. f i n ray. i n t e r p o l a t i o n was  A cotton thread used f o r  f i x e d t o one end of the base l i n e which cuts  the f i s h length scale at the point of i n t e r c e p t of the r e g r e s s i o n  18 l i n e (plate 3 ) .  Plate 3  A nomograph used i n back c a l c u l a t i o n of length of the Fraser R i v e r white sturgeon  Thus the nomograph, by method of s i m i l a r t r i a n g l e s , solves the r a t i o F i s h length at age x _ F i n ray measurement at age x F i s h length at capture F i n ray measurement at capture where the length at capture i s f i r s t corrected for the length at t h e o r e t i c a l zero f i n ray measurement.  19 Results of the back c a l c u l a t i o n are given i n Tables 4 and 5. The c a l c u l a t e d lengths at d i f f e r e n t ages were averaged and the data used to construct the curves of growth (Figs 7, 8 ) . Lengths were averaged only up to age t h i r t y - s i x because t h i s age there were only a few specitnents.  after  C a l c u l a t e d lengths  were p l o t t e d u s i n g the Walford transformation by p l o t t i n g length at time t + 1 against length at time t ( F i g s . 2.  9 and 10).  Growth of the d i f f e r e n t year classes To study growth of the d i f f e r e n t year c l a s s e s ,  lengths  at the d i f f e r e n t ages w i t h i n year classes were averaged, and p l o t t e d against t h e i r ages i n the d i f f e r e n t calendar years throughout t h e i r l i v e s ( F i g s . 1.1, 12).  3.  R e l a t i o n s h i p between s i z e year classes  and growth i n the d i f f e r e n t  To study the r e l a t i o n s h i p between s i z e and growth i n the d i f f e r e n t year classes the method of L a r k i n , Terpenning and Parker (1956) was employed.  The instantaneous growth r a t e s for  the d i f f e r e n t year classes were c a l c u l a t e d and p l o t t e d against fork lengths at the beginning of the year of growth ( F i g s . 13, 14).  The instantaneous growth rates were obtained by t a k i n g  log^Q average fork length at age t + 1 - log^Q average fork length at age t .  2.0  Growth i n weight of the Fraser River white sturgeon Growth i n weight of the Fraser River white sturgeon was studied by two methods: 1) by averaging the weights of f i s h of the same age at the time of capture and p l o t t i n g these against age (Figs 15, 16); and 2) by c a l c u l a t i n g the weights of f i s h at various lengths u s i n g the length/weight r e l a t i o n s h i p ( F i g . 17). The length/weight r e l a t i o n s h i p was obtained by p l o t t i n g the logarithms of weights against the logarithms of lengths (separating sexes), and f i t t i n g regression l i n e s on these p l o t s by the method of least squares.  The equations for these l i n e s  were then used to c a l c u l a t e the weight of the f i s h at  different  lengths.  Age at f i r s t spawning and i n t e r v a l s between spawnings Age at f i r s t spawning and i n t e r v a l s between spawnings were studied by examination of cross sections of the f i r s t f i n ray for zones of crowded a n n u l i and from the study of f l u c t u a t i o n s i n growth curves.  The method followed i s that of Roussow (1957).  Roussow (o£ c i t ) i n d i c a t e d that the growth of gonads causes great r e t a r d a t i o n i n the r a t e of growth of the f i s h , and that during spawning the males and females lose 1/10 and 1/5 r e s p e c t i v e l y , of t h e i r body weight through exudation of m i l t and eggs. differences i n the growth r a t e of the f i s h and the  These  fluctuations  i n the body weight are r e f l e c t e d i n the curves of growth i n length and weight.  The r e t a r d a t i o n of growth during the b u i l d i n g  up of eggs and sperms i s marked i n the f i n ray s e c t i o n s .  During  t h i s p e r i o d , a n n u l i are l a i d down c l o s e to one another forming a narrow zone of concentrated a n n u l i which Roussow c a l l s " b e l t " .  21 A f t e r spawning, normal growth i s resumed and a n n u l i are l a i d , down at wider i n t e r v a l s .  Roussow suggested that normal growth i s  resumed no l a t e r than the year immediately f o l l o w i n g spawning. Thus by counting the a n n u l i up to the end of the " b e l t " the age at f i r s t spawning was determined.  I n t e r v a l s between spawnings  were then determined by counting the number of a n n u l i between successive " b e l t s " . Specimens selected for t h i s study were those males i d e n t i f i e d as mature or spawned, and i n the females those f i s h which had r i p e eggs.  In a d d i t i o n to these, some f i s h which were  i d e n t i f i e d as immature were examined to determine whether there was any n o t i c e a b l e difference i n the arrangment of the a n n u l i .  M o r t a l i t y rates i n the Fraser R i v e r white sturgeon In unexploited f i s h stocks i t i s p o s s i b l e to obtain d i r e c t l y an estimate of n a t u r a l m o r t a l i t y by studying the age frequencies i n a sample taken randomly.  In e x p l o i t e d p o p u l a t i o n s ,  however, m o r t a l i t y r a t e thus obtained i s a component of both n a t u r a l and f i s h i n g m o r t a l i t y .  If the magnitude of f i s h i n g i s  known, the n a t u r a l m o r t a l i t y i s obtained by " s u b t r a c t i n g " f i s h i n g m o r t a l i t y from the t o t a l m o r t a l i t y . sturgeon, i t i s d i f f i c u l t  For the Fraser River  to estimate separately the magnitude of  e i t h e r f i s h i n g or n a t u r a l m o r t a l i t y for the f i s h e r y i s only i n c i d e n t a l t o the salmon f i s h e r y .  These, therefore,  can only be  a r r i v e d at i n d i r e c t l y and w i t h a c e r t a i n amount of s p e c u l a t i o n . The t o t a l m o r t a l i t y r a t e was obtained by p l o t t i n g the logarithms of the number of f i s h i n various age groups against  22 t h e i r ag®, o b t a i n i n g a catch curve the slope of which was used to estimate the t o t a l m o r t a l i t y r a t e .  Ricker (1947) has shown  that t h i s method of e s t i m a t i n g m o r t a l i t y r a t e i s affected by three p r i n c i p a l sources of e r r o r , one of which i s systematic and the other two random.  The systematic e r r o r a r i s e s from the  unequal v u l n e r a b i l i t y of f i s h of d i f f e r e n t ages to the gear.  fishing  In the case of sturgeon,young f i s h w i t h prominent  scutes are more  vulnerable to the f i s h i n g gear than old f i s h  w i t h degenerate scutes.  In t h i s f i s h e r y too, u s i n g a r e l a t i v e l y  standard mesh gear, which i s d i c t a t e d by the salmon f i s h e r y , the data from o l d ages where the f i s h are bigger than the s e l e c t i o n range are not w e l l represented.  gear's  Random errors include  sampling e r r o r and errors due to f l u c t u a t i o n s i n the strength of the year c l a s s e s .  Phyca (1956) i n d i c a t e d that the white sturgeon  of the Sacramento R i v e r , C a l i f o r n i a , produced a strong year c l a s s at roughly an i n t e r v a l of ten y e a r s . To separate the t o t a l m o r t a l i t y r a t e i n t o n a t u r a l and f i s h i n g m o r t a l i t y r a t e s , i t was assumed that i n unfished c o n d i t i o n the sturgeon could l i v e to a maximum age of f o r t y , and f i f t y y e a r s .  forty-five,  Catch curves were a c c o r d i n g l y constructed and  t h e i r slopes used to estimate n a t u r a l m o r t a l i t y r a t e s .  The  f i s h i n g m o r t a l i t y rates were then obtained by s u b t r a c t i n g n a t u r a l . m o r t a l i t y estimate from the estimated t o t a l m o r t a l i t y r a t e .  T h e o r e t i c a l y i e l d at d i f f e r e n t r a t e s of n a t u r a l and f i s h i n g mortality To obtain the lengths used i n these c a l c u l a t i o n s , c a l c u l a t e d lengths f o r males and females were combined and a growth curve i n length on age c o n s t r u c t e d .  The points were  23 smoothed out free hand and the length at d i f f e r e n t ages obtained. For these lengths corresponding weights were c a l c u l a t e d on the b a s i s of the length/weight r e l a t i o n s h i p .  Since the  equations  representing the length/weight r e l a t i o n s h i p s for males and females were much the same, any of them could be used for o b t a i n i n g the weights at d i f f e r e n t ages i n the combined data. The equation for the females was a r b i t r a r i l y chosen for these computations.  The method of Ricker (1945) o u t l i n e d i n Ricker  (1958) for e s t i m a t i n g e q u i l i b r i u m y i e l d was found to the the most appropriate for these computations, because growth i n the Fraser R i v e r white sturgeon does not conform to von B e r t a l a n f f y • s law of growth.  The data presented cover a range of age from one to  t h i r t y - s i x , w i t h the corresponding length and weight i n t e r v a l s of 9.0 to 71.7" and 0.154 to 106 pounds r e s p e c t i v e l y .  For these  c a l c u l a t i o n s , n a t u r a l m o r t a l i t y rates of 0.05, 0.089, 0.10 were choseq and for each of these y i e l d s c a l c u l a t e d for 0.025, 0.04, 0 . 0 5 , 0.06, 0.075, 0.13, and 0.25 l e v e l s of f i s h i n g m o r t a l i t y .  24  RESULTS  Age Determination Table I shows the r e s u l t s of the age determination, and F i g . 3 , the age composition for the Fraser R i v e r white sturgeon. The data on age composition do not i n c l u d e small sturgeon taken from Dewdney Slough. From these data i t i s seen that ages i n the commercial catches vary from seven to seventy-one y e a r s .  Age group eleven  dominated the catches, followed by age group t h i r t e e n .  Apparently  the f i s h e r y i s operating most e f f e c t i v e l y on age groups nine t o sixteen.  F i g . 4 shows that these ages should f a l l w i t h i n a length  i n t e r v a l of 30 t o 42".  From the data, however, i t i s apparent  that w i t h i n any one age group there i s great v a r i a b i l i t y i n the length of f i s h .  This r e s u l t s i n an extensive overlapping of  lengths of f i s h of d i f f e r e n t age groups.  Within length group  30 to 42", seventeen age groups are represented.  Length, t h e r e f o r e ,  i s a poor index of age i n white sturgeon.  Growth of the Fraser R i v e r white sturgeon 1.  Growth i n length Table I I gives the average e m p i r i c a l fork length at time  of capture for the male and female sturgeon and the data are presented g r a p h i c a l l y i n Figs 5 and 6.  These two curves are very  25 Table I  Length and age of the male and female white sturgeon of the Fraser River May 1 to October 28 1962  Serial Number  Fork Length  214 216 217 218 240 212 211 121 213 196 202 210 239 198 200 118 197 199 245 117 241 116 194 23 236 231 143 114 66 19 234 251 235 90 232 18 77 72 81 55 34 14  12.0 12.0 13.0 13.0 13.0 14.0 14.5 15.0 15.0 15.0 15.5 16.5 17.0 18.5 19.5 21.5 22.0 22.5 24.0 24.0 24.5 29.0 29.0 30.5 30.5 31.0 31.5 31.0 31.0 31.0 31.5 31.5 31.5 31.5 32.0 32.0 32.0 32.0 32.0 33.0 33.0 33.0  Age 4 4 3 5 5 4 7 6 4 4 6 7 10 9 10 5 9 12 5 9 6 8 10 7 14 8 8 9 9 12 23 _ _  11 11 10 17 8 11 23 9 11 12  Serial Number  Fork Length  Age  12 160 134 224 163 246 225 233 222 137 142 246 16 250  33.0 33.0 33.5 33.5 33.5 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.5 34.5 35.0 35.0 35.0 35.0 35.0 35.0 35.5 36.0 36.0 36.0 36.0 36.0 36.0 36.0 36.0  13 10 11 12 10 13 12 11 16 14 12 13 15 9 12 9 13 10 10 11 12 11 16 10 12 16 12 12 13 10 16 10 10 11 12 17 16 10 13 16 11 9  88  S3 68 50  52:  32 43 36 174 149 21 223 190 109 64 175 173 171 162 131 127 60 249 189 185 164 148 129  males  Serial Number  Fork Length  138 186 152 74 112 115 44 40 17 151 168 95 41 126 24 133 230 229 184 130 106 91 150 89 155 93 255 166 254 252 139 107 220 238 153 219 237  36.5 37.0 37.0 37.5 37.5 38.0 38.0 38.0 38.5 38.5 39.0 41.0 41.0 41.5 42.0 43.0 43.0 44.0 45.5 45.5 46.0 47.0 48.0 48.0 48.5 50.0 53.0 57.0 59.0 59.0 62.0 67.0 73.5 75.5 79.0 80.0 91.25  A  8.  11 10 10 10 12 13 16 12 15 11 11 16 10 12 19 14 19 11 16 10 16 43 11 18 15 16 24 20 24 24 22 43 32 33 63 39 36  e  Table I  Length and age of the male and female white sturgeon of the Fraser River May 1 t o October 28 1962 (continued)  Serial Number  Fork Length  Age  Serial Number  Fork Length  Age  215 191 192 124 203 122 208 201 209 120 188 195 53 48 1 172 176 65 73 58 141 136 42 33 94 108 35 180 157 248 2 132 57 6 3 38 87 20 62  12.0 12.0 12.0 13.0 14.0 16.0 18.5 18.5 18.5 20.5 23.0 25.0 27.0 30.0 30.5 31.0 31.0 31.5 32.0 32.0 32.0 32.0 32.0 32.0 32.5 33.0 33.0 33.0 33.0 33.0 33.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0 34.0  4 3 4 6 4 7 10 12 7 10 6 6 12 11 12 7 13 11 12 8 14 9 12 13 13 10 15 14 9 13 13 8 13 11 15 13 13 12 16  128 97 98 29 146 158 181 31 25 8 227 92 147 167 179 37 15 22 226 247 82 86 182 78 59 113 10 145 79 47 26 27 28 30 11 7 96 221 89  34.5 35.0 35.0 35.0 35.0 35.0 35.0 35.0 35.5 35.5 36.0 36.0 36.0 36.0 36.0 36.0 36.0 36.5 37.0 37.0 37.0 37.0 37.0 37.5 38.0 38.0 38.0 38.0 38.5 39.0 39.0 39.0 40.0 40.0 40.0 40.0 40.0 40.0 41.0  12 11 11 13 9 14 11 13 14 12 16 12 13 11 15 13 10 13 11 13 11 13 10 12 11 11 15 11 13 13 11 11 20 13 14 15 23 19 18  females  Serial Number  Fork Length  Age  46 13 9 104 56 111 85 103 256 140 165 125 102 80 253 243 105 242 237  42.0 42.0 42.0 43.0 44.0 48.0 46.5 48.0 49.0 51.0 51.0 51.5 55.0 55.0 65.0 71.0 84.5 89.0 91.25  19 19 18 13 15 12 20 16 22 16 14 11 19 26 19 35 63 71 36  20  25  AGE Fig.  3  Age distribution  30  IN Y E A R S  in the Fraser River  commercial  citches  white  sturgeon  50  40  ™  30  u. o  20 LU  cn X Z  10  r~h n 00  3 6  ' ' — —  '  1^.' ' • • » ' • i» ~. ^ r M . - M ( M f \ 4 o i f ^ r O ( * ) r » ) r<") •< T J T  FORK Fig  4  Length frequency wh:tu  T  O <M LO in m /-I  m m  t i n  in ui  LENGTH  r-i CO  IN  1  0  <o  rf  rn r>  -1  n 0D «» co  INCHES  distribution of the Fraser sti;!'aeon  r 1 1  River CO  29 similar.  They show a fast growth rate up to the tenth year, but  t h e r e a f t e r the curves f l a t t e n off suggesting a slower growth r a t e . There i s i n d i c a t i o n that a f t e r  the twentieth year of growth a  f a s t e r growth r a t e i s r e v i v e d , but w i t h the great v a r i a b i l i t y i n length observed, and the few specimens examined at the older ages, these curves would not appear to r e f l e c t the growth of sturgeon at older ages very p r o p e r l y .  The data, however, show that there  i s no apparent difference i n the growth of the male and female sturgeons up to the age of twenty years.  Results of the back c a l c u l a t i o n Results of the back c a l c u l a t i o n s are given i n Tables I I I and IV.  These r e s u l t s i n d i c a t e that growth i n length i n the  white sturgeon i s very v a r i a b l e .  In the males, one-year-old  f i s h v a r i e d between 4.6 to 14.4", t e n - y e a r - o l d f i s h between 21.5 to 4 0 . 2 " , and the f i f t e e n - y e a r - o l d f i s h between 25.9 to 48.2". The same v a r i a b i l i t y i s r e f l e c t e d i n the growth of the females of which one-year-old f i s h v a r i e d between 4.9 to 12.0", ten-yearo l d f i s h between 21.0 to 43.0" and f i f t e e n - y e a r - o l d f i s h between 31.0 to 57.0". variable.  Some f i s h s t a r t w i t h a poor growth rate and maintain  t h i s throughout i n growth.  The growth of the i n d i v i d u a l f i s h i s a l s o  t h e i r l i f e , while others show some compensation  L i k e w i s e , some f i s h which show a b e t t e r growth i n  t h e i r e a r l y l i f e may maintain i t , w h i l e others show a poor growth r a t e i n the l a t e r  years.  Calculated lengths do not show L e e ' s phenomenon (apparently slower growth r a t e at young ages of r e l a t i v e l y older fish).  However, the reverse of Lee's phenomenon seems to be  30 Table II  Average e m p i r i c a l fork length at time of capture f o r the male and female white sturgeon of the Fraser R i v e r , May 1 t o October 28, 1962  Age Frequency 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 32 35 43 53  Av.L.  Range  4 1 1 2 6 8 16 16 13 8 4 6 9 2 1 2 3  13~25 13.00 24.50 22.50 28.75 29.81 35.68 34.92 35.12 36.69 35.13 37.08 39.56 34.00 40.00 42.50 45.67  12.0-15.0  42.0-43.0 32.0-57.0  1 2 2  62.00 39.75 59.00  31.5-48.0 59.0-  _  _  1 1 1 1  _  _  _  mm  _  —  73.5 75.5 67.0 53.0 males  14.5-30.5 16.5-32.5 18.5-36.0 19.5-45.5 31.5-44.0 31.0-41.5 32.5-47.0 33.0-40.0 32.0-48.5 34.0-50.0 32.0-36.0  — —  Age Frequency 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 35 36 63 71  1 3  Av.L.  Range  12.0 12.76  12.oIl4.0  •a  _  2 2 4 4 15 10 15 6 5 4 _  mm  25.00 33.00 34.13 31.25 37.07 32.50 36.30 37.42 35.50 41.25  18.5-31.5 32.0-33.0 32.5-36.0 18.5-37.0 31.0-51.5 18.5-44.0 33.0-43.0 32.0-51.0 30.5-44.0 30.0-48.0  mm  2 4 2  41.50 47.25 43.25  41.0-42.0 40.0-65.0 40.0-46.5  1 2  47.00 36.00  32.0-40.0  _  mm  _  1 1 1 1 1 females  55.00 71.00 91.25 81.00 89.00  —  mm mm  10  Fig  5  15  20  25  30 AGE  35 40 IN YEARS  45  50  55  60  65 LO  Growth in length of the Fraser River male white sturgeon (Average empirical fork length by age groups) i_.  10  IS  20  25  30 AGE  Fig.6  35 IN  40  45  50  55  60  65  YEARS  Growth in Length of the Fraser River female white sturgeon (Average empirical fork length by age groups )  7i  33  i n d i c a t e d i n that there i s apparently a higher growth r a t e at lower ages as calculated from older f i s h .  the  This most probably  r e s u l t s from the differences i n the growth rates of the males and females, the data of which were combined to obtain the equation used for back c a l c u l a t i o n .  I t i s evident from these r e s u l t s  that both sexes have a r a p i d growth r a t e i n t h e i r f i r s t year which drops off rather r a p i d l y i n the second year.  Increments from age  two to age sixteen are uniform, averaging 2.34 inches per year. There i s no apparent difference i n the growth of the sexes at these ages.  A f t e r age s i x t e e n , however, s i g n i f i c a n t differences  e v i d e n t , the females growing much f a s t e r than the males.  are Curves  of growth ( F i g s . 7 , 8) based on back c a l c u l a t e d lengths, show that growth i n f i s h older than f i f t e e n years i s i r r e g u l a r showing periods of retarded growth followed by periods of accelerated growth.  The r e s u l t i n g curves, therefore,  r e f l e c t only a s l i g h t  decrease i n growth with age, and do not i n d i c a t e that e i t h e r sex i s growing to a maximum s i z e . transformations  Figs.  9 and 10 show the Walford  for the males and females r e s p e c t i v e l y .  In both  cases these figures i n d i c a t e that although the l i n e s approach the 45° d i a g o n a l , there i s no i n d i c a t i o n that any of them w i l l cross i t , p r o v i d i n g evidence that the white sturgeon does not grow to a f i x e d maximum s i z e .  Therefore the growth of the Fraser R i v e r  sturgeon does not conform to von B e r t a l a n f f y ' s law of growth.  Growth of the d i f f e r e n t year c l a s s e s Fig.11 represents the growth i n length of the female year classes 1945, 1946, 1949, and 1950.  These p l o t s r e v e a l some  n o t i c e a b l e differences i n the growth r a t e s of the d i f f e r e n t year  Table III  sir 203 195 49 86  Ul  59 78 29 31 227 182 144 6 35 165 167 226 11 128 140 37 13 9 46 253 96 243 237  r  8,.8 9,.1 8..9 10..2 9..8 7,.8 7..5 7..3 9.,6 9..4 10.,0 8.,0 4.,9 6.,7 14..3 9..4 6..2 8..8 9.,4 10..4 7.,0 6..3 5..5 9..5 11..2 7.,2 9.,3 12. .0  Average  Back calculated lengths for the female sturgeon of the Fraser River — material collected between May 1 and J' 9..4 14..8 14..8 13..4 12..0 12,.8 10,.8 11,.9 12,.2 12,.5 13..4 9..9 6..8 10.,7 16..9 15..5 9,.5 12,.4 11,.8 15,.1 10,.4 10..2 9..5 10,.0 15,.7 12..0 12..8 14.,0  "• 3 12. .5 17..4 17.,2 16..5 15..5 15.,6 12. ,6 14, .4 15..2 13. 8 16. .1 12. 3 11..7 11..9 18. .5 15..8 10..4 15.,1 14. 0 17.,2 12. .6 14. ,6 11.,5' 11.,0 18. .7 12. ,5 14. ,0 15. .4  -  T 14 20,.4 21..8 20,.5 16,,7 18..8 15..5 15..8 17..6 15..2 18.,0 13.,8 12.,2 15..3 21,.8 18.,0 11,.0 17.,0 15.,5 .19, ,8 13,.7 17.,8 13..2 13..8 19.,7 15.,2 17.,0 17..8  5 23,.2 23,.8 22. .6 20..8 22. .2 16.,2 17.,2 19.,7 18. .0 19..0 14. ,8 13..8 20.,0 25,.8 20..6 12..0 18..1 16..5 23..2 16.,7 21.,3 15..8 16..1 22. .2 15..6 19..1 19..8  5  1  7  24,.0 28,.2 32. .1 24,.4 28, .5 22..8 25..4 25,.9 27..4 17,.2 19,.4 22,.2 26..4 22,.7 25.,7 19,.5 21.,7 21,,8 24. ,1 15,,8 16.,5 14,.2 16.,3 20,,6 21..8 31,.8 34, .2 22,.3 24, .3 14..5 16,.5 21,.2 22, .3 18,.3 19,.6 2S,.6 30, .9 17,.3 17,.6 22,.4 24. .3 16,,7 18. .0 17,.1 13,.6 24..9 27..0 16,,0 17.,3 25,,9 26.,4 22,,0 24. ,6  October 28 ;  1962  ""8"  33,.5 31,.5 27,,5 29..9 26..1 25,.8 28. .1 23.,5 27..0 19.,6 18. ,a 23..6 38, ,4 26, .3 19,,8 23,.6 22, .6 32, .7 20.,0 25. .8 20..3 19..0 31..8 18.,4 23.,5 25. ,0  33,.7 2S,.6 32, ,5 28. ,5 31, ,8 29.,8 27.,3 30.,0 22. .7 22. ,8 26. 4 40, .9 28. .0 24. ,6 28.,9 23..8 34. ,8 20..7 26..0 21..9 20.,1 38. ,6 21.,3 30. .1 26..0  36.6 29.7 31.4 34.5 37.8 32.5 36.4 33.3 34.7 31.8 33.7 30.0 34.2 32.1 34.7 24.8 27.4 25.E 27.4 29.2 30.1 43.2 45.8 29.7 31.0 27.2 30.6 30.1 32.1 25.4 27.0 37.4 40.1 25.3 26.9 29.8 31.0 23.8 25.4 21.0 21.4 41.7 44.9 24.5 25.2 31.7 33.6 29.4 32.4  36..7 37..0 30..5 31..4 30. .6 .7 33,.4 33..6 37..5 2£..5 43. .2 27..8 32. .3 27.;5 25.,0 47..6 25.6 25. 6 34. .6 34.6 32. .4 32.4  34. .0 33.,0 50, 34, 34,.6 39..2 29.,4 4V,E 29..5 34,,2 29.,2 26.,2 45. 28.8 28. .8 35. ,4 35.4 36.,5 36.5  49; ..4 9 ,9  40.,0 31,.4 32. .6 47. .3 50..0 32, ,3 33..5 25,,7 36.,4 31.,8 34, .3 27.,5 • 31..3 53. 6 57..2 30.1 30.,1 31.4 31..4 37. ,8 38. .8 37.8 38.8 40. .0 43.7 43. ,7 40.0  34, 15 35.90 37.,38 39.29 35. 90 37.3£ 35..29 B.73 12.17 14.42 16.66 19.40 21.42 23.34 25.81 28.09 30.42 32.30 34.15  34,.5 55,Ll 35,.0 36,.0 35 .0 41,.7 35,.8 39,.1 33,.2 35,,3 60,.0 • 62, .4 32.4 33.6 32, 33. .6 40. .6 43, ,0 40.6 43.0 47,.4 51,,6 47.4 51.6  .4  41..31 41.31  41.1 37.£ 64,0 35.0 44.2 54. E 54.E  41.9 64.6 37.3 47.1 57.5  43. ,06 46.43 50.18 43.06  36.0 46.0 60.0  38.8 4i.fi 62.5  51.1 64.7  52.8 66.5  53.8 68.5  54.6 70.0  55.1 71.7  57.2 73.2  60.1 75.5  61.4 77.6  63.0 6-.4  64.6 82.0  66.1 84.0  67 6 69 5 86.0 89.0  70 6 89.2  49.50 51.10 58.30. 60.70 61.;0 63.15 64.15 66.35 68.85 70.90 72.50 74.30 76.05 78.30 79.35 80.20  Table IV  Back calculated lengths for Ctie male white sturgeon of the Fraser River  sir-  2  3  Z  10.2  13. .1 11. .2 12. .6 13, .5 9, .5 11. .9 16. .0 13, ,9 12. .6 11. ,3 12. .6 15. .8 17. .5 13. .0 16. .6 13. .7 7, .6 17, .8 15. .0 15. .1 16. 17. ,1 10. .8 15, .2 11, .5 16, .0 13, ,4 15. .4 13. .6 11. .8 12. .© 14, .0 14. ,5 15. ,6 15. ,5 11. .2 16. ,4 15, .0 15. .3  15 . 0 12, .3 18, .2 15 .2 11, .0 15, .0 18. .0 16. .2 15, .0 13, .2 16. .0 19. .6 19. .8 15, .8 .8 18. .4 12. .8 19, .0 17, .0 17, .4 19, ,2 21. .2 14, .2 16. .2 13. .0 17. .4 15, .8 20. .6 14. .6 12. .5 14. .0 15, .0 18. .9 19, .3 17, .5 12 .3 20, .1 16. .1 16. .2  213 193 23 77 210 197 83 231 162 171 232 186 228 163 149 50 34 233 175 229 148 151 14 40 36 127 12 91 154 133 183 95 184 93 106 164 24 230 166 -252 219 153  1  8.2 6.2  6.6 7.3 6.8 10.2 8.2 7.5 6.2 4.6 8.4 6.7 10.3 8.8  10.2  8.5 5.0 8.9 8.5  8.2  10.0 9.8 5.9 8.9 4.9 9.5 7.7 6.9 9.4 6.8 9.1 9.1 9.3 9.6 8.9 9.8 14.0 7.9 10.6 14.4  6.2  10.4 11.5  11.2  8.9 11.0 12.3 11.5  11.2  8.4 10.6 12.6 14.6 11.4 14.7 11.1 6.3  14.2  12.6 13.3 14.0 14.5 7.6 11.7 9.9 14.1 12.0 9.7 12.8 9.6 11.4 11.9 13.6 10.6 ol.4  10.6 16.1 12.8 14.0 19.1 8.5  T"  22.  8  22.  7  4  15, .5 27, .2 20, .2 12, ,4 17, ,4 23, .7 .5 19, .6 23, ,0 19, .4 23. .2 27. .2 19, .6 27. .0 20, .7 20. .0 23 .6 20, ,4 23, .7 23. .1 27. .1 19, .8 23, .0 20. .0 21, .0 19. .6 27, .4 16, .2  22,  2 2.2 18. .4  17. ,1 26, .8 25. .4 21, .9 14. .7 15, .3 21, .4 20. .9 17. .4 18. .8 19. . 5 - 20, .8 31. ,5 32. 24. 5 .6 29. ,4 2 5 , 9 18. .2 19. ,0  ,0 22.  22,  20. 1  12. .9 .9 17, .3 11. .8 16. .0 19. .3 19. .2 17. .4 19. .1 17, .0 21. .6 23. .3 18. .4 24. ,4 19. ,4 17. . 9 . 21. .4 19. .0 21. .0 21. ,2 25. .1 18. .3 19. .6 16. .6 19. .6 17. .4 25. ,8 15. .6 17, .0 14. .9 16. .4 25. ,2  22. ,2 20. ,3  30.5  24.2  13.8 20.0 27.3  26.2  25.4 25.6  22.5 26.6  28.2 24.4 29.4  26.2  21.> 26.0 23.4 23.9 24.6 29.8 21.1 25.0 21.0 23.5 21.1 30.6 18.0 25.8 20.8 18.5 31.7 29.1 23.4 16.6  22.5 19.4  22.6  8  35.6  32.0 20.3  10'  5  31, .6 16. .0 20, .8 32. .3 30. .0 2S. .2 28. ,5 27. .8 30. .5 30. .3 29. .2 32. .5 29. ,4 25, .9-. 28. .5 25. .5 31. .6 27. .1 31. ,2 23. .4 26. .9 21. ,2 23. .9 23. .2 32. .6 20. .2 29. .8 23. .0 21. .4 34, .9 32. .1 25. .8 18. .6 23, .6 20. .4 ,8 ii. .8 33. ,4 21.  25.  2  21, .6 33, .6 31. .0 31. .4 29. .8 27, .8 33, .5 32. .8 30. .2 35. ,3 31. .0 27. . 1 ; 31. .0 28, .8 35. .7 29. .4 33. .2 24. .6 29. .4 24. .4 26. .1 24. .4 34. ,6 21. .4 32. .8 24, .2 27. ;5 35. .9 33. ,7 28. .8 19. .6 26. .0 .7 28. ,7 39. .8 34. 6 21. .7  22.  Average 8 . 4 4 11.80  14. ,36  16. .84  19. ,45 21. ,83 24.10  0 .8  27.  U  35. .0 35. .0 32, .0 37. .0 33. .0 33. .0 39. .6 33. ,6 29, .8" 32. .6. 33, .0 34, .0 31. .9 30. .8 39. ,2 40. .6 34. .1 31. ,0 35. .8 38. .5 28, .0 29. .0 31. .2 •34, .0 28. ,2 25. .8 23. .7 31. .5 26. .6 28, .1 36. ,7 39. .5 26. .0 21. .6 37, .6 35, .1 25, .4 26. .6 31, .1 34. .0 37. 36. .8 37. .0 35. ,0 30. ,2 31. ,2 21. .5 .6 27. ,0 28. .8 24. .8 26. ,7 34. .6 30. .9 40. .2 41. ,8 36. 35. .7  8 , 22,  October 28, 1962  15  VI  IT  30, .6 38. .0 31, .0 35 .7 29. .3 41. .6 28. .2 36. .6 31. .8 36. ,4 40. .4 39. .4 33. .4 24. .8 30. .4 29. .0 37, .2 42. .2 37. .2 23. .6  33. .0 45. .2 31. .0 40, .8 34, .1 38 .8 41, .9 43, .0 37, .8 27 .0 32. .4 31, .4 35, 44. ,1 37, ,6 24. .7  8 8  22. 2 22,  material collected between Kay 1 and  33. .9 42. .3 35. .7 39, .2 43, ,4 45, .5 40. ,2 2E,.2 34. .2 33, .3 43. 46. .8 38. 25.  37. .0 41. .0 45. ,4 48. .2 45. .5 29. .6 35. .6 35. ,0 44. ,7 48. 5 40. e 25. 5  .8 0 .2 8  45, ,5 50. ,0 46. .0 31, .2 37. .9 37. L 46. .5 49. ,2 42. ,4 26. ,4  36.29 37.71 39.42 41.33 ,71 39. ,33 .94 36. 42 41. .29 37. 29. ,25 31. 50 32. .93 33..94  34.L 3£.6 35.4 50.3 51.4 45.2 27.9  36.0 3S.9 41.6 52.8 52.8 49.8 28.S  42.0 43.0 56.2 54.7 53.8 29.6  55.8 56.6 56.2 58.0 30.1 31.5  5S.0 59.0 60.4 63.4 32.7 33.2  67.0 34.0  68.6 35.1  70.0 35.8  71.0 37.2  72.0 37.4  79.0 39.2  3o  31  52  33  34  74.9 41.6  75.2 42.9  75.8 44.9  76.6 77.6 4G.6 47.8  35  78.0 49.1  78.4 49.6  41.34 42.94 42.74 46.23 47.00 48.23 49.57 51.87 53.33 51.85 52.90 54.80 55.85 57.80 58.90 60.05 61.20 62.20 63.35 63.80  O  5  10  15  20  25  AGE IN Y E A R S Fig 7. Growth in length of the female Fraser River White sturgeon (Average calculated fork length by age groups)  o  o o  o o o o o  o  e  o  e  9  o  o  o  o  o  o  e 4  o  o  o  o  o  0  o o o o o o o o  5  10  15  20  AGE Fig 8. sturgton  Growth in  25  30  35  IN YEARS  length of the male  (Average calculated fork  Fraser  River white  length by age groups).  38  LENGTH Firj  9  Walford  AT  transformation River  male  TIME of  T  calculated  white  lengths  sturgeon.  of the  Fraser  39  LENGTH Fig IQ  Walford  AT TIME  T  transformation of calculated lengthsof Fraser white sturgeon.  River female  classes.  Year c l a s s 1945 had a slow growth r a t e . ' From 1947 to  1951, there was only a s l i g h t difference between the length of the f i s h of the 1945 year c l a s s arid the length of the 1946 year c l a s s . A f t e r 1961, f i s h of year c l a s s 1946 exceeded i n length f i s h of the 1945 year c l a s s .  In 1960 f i s h of the year c l a s s 1949 were of  the same length as f i s h of the year c l a s s 1945 i n s p i t e of the fact that the l a t t e r were four years o l d e r .  A f t e r 1960, f i s h of the  1949 year c l a s s a t t a i n e d greater lengths than those of the 1945 year c l a s s . In the  males ( F i g . 12) s i m i l a r differences i n the  growth of the year classes are e x h i b i t e d .  F i s h of the year c l a s s  1950 were exceeded i n length by f i s h of the 1951 year c l a s s i n the eighth year of l i f e and by f i s h of the 1952 year c l a s s i n the tenth year of  life.  A n a l y s i s of growth i n the d i f f e r e n t calendar years was attempted.  The r e s u l t s , however, did not show a d e f i n i t e trend.  This most l i k e l y i s due to the fact that year classes are not w e l l represented,  but could a l s o r e s u l t from the differences i n  the growth rates of the year c l a s s e s .  R e l a t i o n s h i p between s i z e and growth i n the d i f f e r e n t year classes F i g s . 13 and 14 represent the r e l a t i o n s h i p s between s i z e and growth i n the d i f f e r e n t year c l a s s e s . show that the instantaneous  These graphs  growth r a t e declines as the  increase i n s i z e which i s as expected.  fish  However, they a l s o  i n d i c a t e that growth p o t e n t i a l s at the d i f f e r e n t s i z e s are variable.  This may be due s t r i c t l y t o sampling e r r o r , but may  50 L  1945  '46  Fig 11  V  '48  'Aa  '50  ' 5l  '52  '53  '54  CALENDAR  Calculated  growth  female  '55  '56  '57  '58  '59  '60  YEARS  histories of the year classes of the Fraser  River  white  sturgeon-  '61  '62  CO  o  CD  z  UJ  1949  50  '51 '52 *53  '54 '55  CALENL.AR Fig 12  '56 '57 '56 "59  '60 '61  %2  YEAR  Calculated growth histories of the year classes of the Fraser River male white sturgeon  — iU J  25  year class 1946  <  year class 1945  cm  J  o oc o  20  co 15 O  UJ  10  < — i  0  10  15 FORK  Fig 13  Relationship  between  20  25  30  LENGTH  IN  size  growth  year  and  classes.  35  AO  45  INCHES of the  different  female  year class 1943  5  IO  15  20  FORK Fig 14  Relationship  25  30  LENGTH  between s i z e  IN  35  40  45  INCHES  a n d g r o w t h of t h e different  male year classes.  a l s o i n d i c a t e changes i n the feeding behaviour of the f i s h ;  for  example, a change from an i n s e c t i v o r o u s to a p i s c i v o r o u s d i e t , or changes i n the abundance of food consequent to changes i n the n a t u r a l environment or when f i s h migrate from one l o c a l i t y to another.  Changes i n the physiology of the f i s h as they pass  through; one maturity stage to another would a l s o contribute to these v a r i a t i o n s . Trends i n the growth of the year classes i n the d i f f e r e n t calendar years were not revealed by t h i s method. trends may e x i s t but due to scanty data, i t i s d i f f i c u l t  These  to  b r i n g them out by the usual procedures.  2.  Growth i n weight Table V summarises the growth i n weight for both sexes of  the Fraser R i v e r white sturgeon. g r a p h i c a l l y i n F i g s . 15 and 16.  The data are presented The data show that growth i n  weight, l i k e growth i n length, i s characterised by great variations.  Weights w i t h i n age groups vary so much that weight,  l i k e l e n g t h , cannot be used as an index of age.  Growth i n  weight of both sexes i s very s i m i l a r and i s characterised by very low increments up to age s i x to seven.  A f t e r t h i s age,  the rates of growth i n weight i n both sexes increase uniformly up to age f i f t e e n .  From age f i f t e e n the increments i n weight  seem to be very h i g h , but due to scanty data t h i s i s not w e l l represented on the graphs.  46  Table V  Average e m p i r i c a l weight f o r male arid female white sturgeon of the Fraser R i v e r , May 1 t o October 28, 1962  Age Frequency Av.W. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 32 33 35 36 39 43 53 63 71  Range  1 5 3 4 2 7 12 19 16 13 9 6 5 8 3 1 2 3  0.50 0.51 1.50 1.43 4,29 4.83 8.83 9.41 10.44 11.04 14.50 12.57 14.58 22,31 11.58 10.50 20.50 33.00  19.25-21.75 9.00-56.00  1 3 2  67.00 14.58 49.00  7.75-26.00 46.00-52.00  _  _ _  1 1 _  —  mm  _  mm  mm  95.25 124.0  mm mm mm  _  1 1 1 1  0.39- 0.64 0.50- 2.50 0.71- 3.25 0.52- 8.00 0.97-11.00 1.50-11.00 1.00-20.00 7.00-17.00 7.75-19.50 8.50-33.50 7.50-23.00 9.00-31.00 9.00-44.50 8.75-15.00  _  110.0 115.0 35.00 132.0  _  males  mm mm mm mm mm mm  Age Frequency Ay.W. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 32 33 35 36 39 43 53 63 71  —  mm  —  mm  Range mm  —  3 3 2 3 5 14 10 17 7 8 5  3.67 3.50 8.50 9.83 7.70 14.47 11.40 12.60 13.07 13.13 14.30  3.00- 4.00 1.00- 8.00 7.00- 8.00 9.00- 10.50 1.50- 14.25 8.00- 38.00 1.25- 29.25 8.00- 27.00 8.00- 31.00 7.00- 26.00 7.00- 29.00  5 3  19.42 32.90 26.92  17.33-21.50 15.00-72.00 15.00- 35.00  1  28.00  mm  2 —  —  —  mm mm  mm  mm  mm  1  45.00  mm  mm  mm  —  1 1  110.0 218.0 mm  —  mm mm  mm  mm  mm  mm  1 1  342.0 173.0  females  180  e o 0 0 9  0  Fig15.  5  °  10  15  Growth in weight of the  20  25  Fraser River  30 AGE  IN  35 YEARS  AO  male white sturgeon  45  50  55  60  (Average weight by age g r o u p s )  65  48  0  15  20 AGE  F i g 16  Growth  in weight  25 IN  YEARS  of the F r a s e r R i v e r f e m a l e  (Average  weight  by  age  white  groups)  sturgeon  49  Length/weight r e l a t i o n s h i p s Fig.  17 shows the l o g a r i t h m i c p l o t s of weight against  length for the Fraser River white, sturgeon.  Regression l i n e s  f i t t e d on these p l o t s by the method of least squares are Log W = -8.73 + 3.13 Log L  for the male  Log W = -8.79 + 3.15 L o g L  for the female  g  e  e  e  These two equations are much the same, which shows that the growth of weight i n r e l a t i o n to length i n both sexes i s similar.  The data used to obtain these equations, however,  contain only a few specimens of both sexes at lengths greater than 45".  Therefore, the statement made above would appear to be  true only for the f i s h of length below 45".  As the females grow  bigger and approach t h e i r spawning stages, t h e i r increments i n weight are much l a r g e r than those of males due to the expansion of the o v a r i e s .  This would give the equation for the females a  much higher slope than that for the males. Table VI gives the average and c a l c u l a t e d weights at different  lengths, and the data are presented g r a p h i c a l l y i n  Fig.  From t h i s table and graph, i t i s evident that growth i n  18.  weight i n both sexes i s s i m i l a r u n t i l the f i s h a t t a i n 30" i n fork length.  A f t e r t h i s l e n g t h , the females add on more weight than  the males for the same increment i n length.  The difference i n  weight increments becomes p r o g r e s s i v e l y bigger as the f i s h t h e i r size i n length.  increase  The difference i n growth i n weight among  the sexes, i n bigger f i s h , i s shown more c l e a r l y i n F i g . 19 where average lengths at d i f f e r e n t ages were used to c a l c u l a t e the  50 Table VI  Length 12" 13 14 15 16 17 21 22 23 24 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 46 47 48 49 50 51 . 53 55 57 59  Comparison between e m p i r i c a l average weight and c a l c u l a t e d weight f o r male and female white sturgeon of the Fraser River May 1 t o October 28  Average Weight 0.42 0.53 0.58 0.72 _ _  1.00 2.00 2.00  Calculated Weight  ! 0.384 0.494 0.625 0.774 mm mm  1.15 2.22 2.56 mm mm  4.00 5.75 —  3.38 6.10 _ _  7.50 10.56 8.96 10.16 11.57 12.13 14.33 14.00 17.00  7.51 8.30 9.17 10.10 11.00 11.90 13.10 14.30 15.50  20.00 19.25 22.38 22.50 45.00 33.60  18.00 19.40 20.90 22.40 25.70 27.60  44.50  33.30  _ _  _ _  _ _ _ _  35.00 — —  56.00 49.00 males  mm mm  40.30 mm mm  50.40 56.10  Average Weight  Caleulated Weight  0.40 0.33 0.57  0.384 0.486 0.619  _ _  1.00  mm mm  0.942  mm mm  _ mm  mm mm  3.00  2.91  9.00 7.00 11.00 8.52 8.43 10.06 11.00 11.66 13.45 13.21 15.25 16.63 21.50 16.11 27.00 27.63  6.25 6.79 7.51 8.38 9.26 10.20 11.10 12.20 13.20 14.40 15.60 16.90 18.30 19.60 21.30 22.80  mm mm  mm mm mm mm  mm mm  mm mm  29.00 28.00  29.90 32.00  36.50  36.50  _ _  mm mm  45.00 —  females  mm mm  mm mm  46.00  51  30  iO 50 60 70 FORK  Fig 17.  Length-weight  20  10  LENGTH  IN  30  iO 50 60  NCHES  r e l a t i o n s h i p for the F r a s e r River wnite stjrgecn  52  10  20  30  FORK Fig 18.  Growth  in weight  calculated  LENGTH of t h e  w e i g h t s at  40  IN  50  INCHES  Froser River white sturgeon different  lengths.  53  180  160  140  120  cn Q §  o  100  a.  80 x o  £  60  40  • 0  20  o O O P  •  5  9  o  10  15 AGE  Fig 19.  20 IN  30  35  YEARS  Growth in weight of the calculated  25  Fraser  River white  weights at different age?.  sturgeon  54 c o r r e s p o n d i n g weights. The c a l c u l a t e d weights obtained by the equations r e p r e s e n t i n g the length/weight r e l a t i o n s h i p d i f f e r  only s l i g h t l y  from the average e m p i r i c a l weights a t lower l e n g t h s . d i f f e r e n c e s , however, can be expected. variability  i n weight  They a r i s e from the  observed at the d i f f e r e n t  from the f a c t that a t some l e n g t h groups represented.  These  l e n g t h groups and  only a few specimens a r e  At h i g h e r lengths t h e r e a r e b i g d i f f e r e n c e s between  the c a l c u l a t e d weights and the average  e m p i r i c a l weights.  As the  sturgeon grow o l d e r and i n c r e a s e i n l e n g t h the c o r r e s p o n d i n g increments  i n weight  assume another p a t t e r n .  The length/weight  r e l a t i o n s h i p a t these h i g h e r lengths should t h e r e f o r e be r e p r e s e n t e d by another e q u a t i o n .  Age a t f i r s t  spawning and i n t e r v a l s between spawnings  Tables V I I and V I I I g i v e the r e s u l t s of examination o f the f i r s t  f i n r a y s e c t i o n s f o r age at f i r s t  between spawnings.  spawning and i n t e r v a l s  From T a b l e V I I i t w i l l be observed that i n  males spawning " b e l t s " were not observed i n a l l f i s h as mature.  identified  In those where the " b e l t s " occurred they were  observed at d i f f e r e n t ages.  Two f i s h showed " b e l t s " a t age  e i g h t t o e l e v e n , and n i n e t o e l e v e n which would suggest that the f i s h spawned f o r the f i r s t  time at about age e l e v e n .  However,  f i s h much o l d e r than e l e v e n y e a r s , eg. s i x t e e n , n i n e t e e n , twentythree and twenty-four year o l d f i s h showed no formation of crowded a n n u l i which would suggest that they had not spawned y e t .  These  data suggest that the male white sturgeon o f the F r a s e r R i v e r ,  55 Table V I I Serial Number 238 139 220 184 219 107 106 91 252 93 230 229 95 244 255  Age at f i r s t spawning and subsequent spawnings i n the Fraser R i v e r white sturgeon (males)  Fork Length 75.5 51.0 73.5 45.5 80.0 67.0 48.0 47.6 59.0 50.0 41.0 42.0 41.0 48.0 53.0  Table V I I I  Weight  Age  124 67 95.25 26.0 110.0 115.0 45.0 33.5 52.0 44.5 21.75 22.50 20.0 26.0 35.0  33 22 32 16 39 43 16 13 24 16 19 11 16 23 24  1st  Spawning Belt 2nd 3rd  19-22 16-18 9 -11 8 -11 10-15 11-14 ——  24-27  27-31  ——  —_  14-16 19-22 not d i s t i n c t not d i s t i n c t 18-22 ——  ——  ——  ——  4th ——  30 — mm  mm mm  28-33 mm mm  Progressive crowding ,a f t e r 9 «. _  ——  _—  mm mm  —_  __  _ _  mm mm  ——  ——  mm mm  —— ——  —— ——  _— —— ——  mm mm  ——  ——  —_  mm mm  _—  Age at f i r s t spawning and subsequent spawnings i n the Fraser R i v e r white sturgeon (females)  Serial Number  Fork Length  Weight  Age  253 46 105 103 102 140 243 242 256 29 82 20 125 92 113 237 K2  65.0 42.0 84.5 48.0 55.0 51.0 71.0 89.0 49.0 35.0 37.0 34.0 51.5 36.0 38.0 91.25 64.5  72.0 16.0 342.0 29.0 45.0 36.5 110.0 173.0 28.0 14.0 15.0 10.5 38.0 12.5 13.5 218 80  19 19 63 16 20 16 35 71 22 11 13 13 11 16 15 36 33  1st  Spawning B e l t 2nd 3rd _  _  _  4th ^  mm  mm mm  _  25-33  36-40  46-49  --  — _  _ _  _ _  _ —  18  — —  — —  ——  — _  — —  — _  _  _ _  — _  — —  _  20-26 6-28  not c l e a r  _  _  —  — _  _  _  _  — —  _ _  ——  — —  — —  — —  — —  — —  _ —  _ _  ——  — —  _ _  — _  — _ - —  _  — _  - -  — -  — _  ——  — _  ——  — —  — _  — —  — —  — —  — —  34 21-28  .  56 s t a r t to spawn at the age of eleven, but that a l l f i s h do not spawn at the same age.  Some f i s h may not spawn u n t i l they are  w e l l over twenty years o l d . Curves of growth ( F i g s . 7, 8) constructed from backc a l c u l a t e d lengths are e r r a t i c around age ten to t h i r t e e n .  There  i s some d e c l i n e i n the growth r a t e from age t e n , and a r e v i v a l of growth a f t e r age t h i r t e e n .  These i r r e g u l a r i t i e s are repeated  at age s i x t e e n to eighteen, and again at age twenty-four to twenty-seven.  While the i r r e g u l a r i t i e s at age twenty-four to  twenty-seven could p a r t l y be due to sampling e r r o r because only a few specimens were averaged at these ages, those at ages ten to t h i r t e e n , and s i x t e e n to eighteen, may be i n t e r p r e t e d as i n d i c a t i n g d e c e l e r a t i o n i n the growth r a t e during the period of gonad maturation.  In the female the sample i s so small that  f l u c t u a t i o n s i n the growth curve could be wholly due to insufficient  data.  I f i t i s assumed that the f i s h resumes normal growth i n the year immediately f o l l o w i n g spawning (Roussow 1957), then among the males (Table VTj) specimen No. 238 spawned a second time i n i t s twenty-seventh year - - f i v e years a f t e r the f i r s t spawning.  This f i s h spawned for a t h i r d time i n i t s t h i r t y - f i r s t  year a f t e r a duration of four years.  Specimen No. 220 spawned  for the f i r s t time when i t was eleven years o l d , and a second time at the age of s i x t e e n — f i v e years l a t e r .  It spawned a  t h i r d time i n i t s twenty-second year a f t e r a period of s i x years. At the time of capture the f i s h looked spawned, and the f i n ray s e c t i o n showed that r e t a r d a t i o n i n growth s t a r t e d i n i t s t h i r t i e t h  57 year.  I f the f i s h spawned i n the year i t was caught, i t would  put the i n t e r v a l between the t h i r d and f o u r t h spawnings at ten years.  Specimen No. 107 f i r s t spawned when i t was fourteen years  old and d i d not spawn again u n t i l nine years l a t e r .  The f i s h  spawned a t h i r d time at the age of t h i r t y - t h r e e and a fourth time at the age of f o r t y . These data then show that i n the Fraser R i v e r white sturgeon the reproductive c y c l e v a r i e s i n the  different  i n d i v i d u a l s , and for an i n d i v i d u a l f i s h the i n t e r v a l between spawnings i s not the same.  Some f i s h spawn again a f t e r an  i n t e r v a l of f i v e years while others take as long as ten years. In females, sections d i d not show subsequent spawnings clearly.  Specimen No. 105 spawned a second time at the age of  f o r t y , seven years a f t e r the f i r s t spawning.  The duration  between the second and t h i r d spawnings was nine years. t h i s spawning the a n n u l i are d i f f i c u l t that durations were s h o r t e r .  to i n t e r p r e t ,  After  but i t seems  Specimen No. 243 showed no  formation of a spawning " b e l t " nine years a f t e r the f i r s t spawning.  This would suggest the period between spawnings could  be w e l l over nine years.  M o r t a l i t y r a t e s i n the Fraser R i v e r white Sturgeon In F i g . 20 i s shown the catch curve for the Fraser R i v e r white sturgeon.  I t w i l l be noted that there i s a c e r t a i n  amount of s c a t t e r of points and the l i n e f i t t e d to these points i s a free hand approximation.  F i g . 4» showing the length/  frequency d i s t r i b u t i o n shows that the f i s h i n g gear i s most  UJ  <  o  in  o o  or ut CD  Z  25 "35" AGE IN YEARS Fraser River white sturgeon 20  Fig 20.  Catch  curve for the  00  s e l e c t i v e at length 32 to 42" which corresponds to f i s h between nine and s i x t e e n years o l d .  The sturgeon then:, i s p a r t i a l l y  r e c r u i t e d i n t o the f i s h e r y at age nine and i s most vulnerable to the f i s h i n g gear (and hence completely r e c r u i t e d ) at age eleven.  The m o r t a l i t y r a t e determined by t h i s catch curve does  not represent the m o r t a l i t y r a t e o c c u r r i n g i n f i s h younger than eleven years. The t o t a l a r i t h m e t i c m o r t a l i t y r a t e between ages eleven and twenty-seven i s 0.197 w i t h a corresponding instantaneous m o r t a l i t y r a t e of 0.219.  At t h i s r a t e f i s h which  were f u l l y vulnerable at age eleven would v i r t u a l l y disappear from the f i s h e r y a f t e r a period of s i x t e e n y e a r s .  Assuming  that i f u n f i s h e d , the sturgeon could l i v e to a maximum of f o r t y y e a r s , we obtain an instantaneous n a t u r a l m o r t a l i t y r a t e of 0.119 The difference between t h i s estimate and the instantaneous  total  m o r t a l i t y obtained i n the above estimate gives an instantaneous f i s h i n g m o r t a l i t y r a t e of 0.100.  L i k e w i s e , i f the l i f e span of  the sturgeon i s extended to f o r t y - f i v e and f i f t y y e a r s , we obtain instantaneous n a t u r a l m o r t a l i t y estimates of 0.101 and 0.089, and the instantaneous f i s h i n g m o r t a l i t y rates of 0.118 and 0.130. That i n an unexploited c o n d i t i o n the sturgeon could l i v e to an age of f i f t y years i s r e a l i s t i c .  Several sturgeon  o l d e r than f i f t y years have been frequently taken i n various places - - Sunde (1961) i n three y e a r s ' c o l l e c t i o n from the Nelson R i v e r , obtained over t h i r t y f i s h over f i f t y years o l d and i n the present c o l l e c t i o n from the Fraser R i v e r 4 f i s h over 50 years were obtained, i n d i c a t i n g that of the estimated t o t a l  fO  mortality  i n the Fraser  contributes  only  at d i f f e r e n t rates  o f n a t u r a l and f i s h i n g  2,1 shows p l o t s o f y i e l d  from the d i f f e r e n t  combinations of n a t u r a l f i s h i n g m o r t a l i t y . from these p l o t s that y i e l d  m o r t a l i t y , a maximum y i e l d  With a high  i s obtained  f i s h i n g m o r t a l i t y , but t h e y i e l d  low  n a t u r a l and f i s h i n g m o r t a l i t y  variable rates  by i n c r e a s i n g t h e r a t e o f  i n weight at the increased  rate  rates.  i f natural m o r t a l i t y i s high  age.  increasing n a t u r a l m o r t a l i t y , the i s lowered.  This  i s because  i n a n y y e a r c l a s s , a t o l d age  o n l y a f e w s u r v i v o r s whose  increase  T h e r e f o r e , to  maximize y i e l d  f i s h i n g should  number o f f i s h  i n a y e a r c l a s s h a s been g r e a t l y  A l t h o u g h t h e f i s h may be s m a l l  there  i n w e i g h t may n o t be b i g  e n o u g h t o make up f o r t h e l o s s i n n u m b e r s .  s t a r t e a r l y enough b e f o r e t h e reduced.  i n s i z e at t h i s e a r l y age, the  number c a u g h t w i l l be b i g e n o u g h t o c o n t r i b u t e weight.  of f i s h i n g  of n a t u r a l m o r t a l i t y are p l o t t e d against  age a t w h i c h a maximum i s o b t a i n e d  in  v a l u e as t h e  r a t e of n a t u r a l  22, y i e l d s at s t a b i l i z e d r a t e s  These p l o t s r e v e a l t h a t w i t h  are  be o b s e r v e d  f i s h i n g m o r t a l i t y , i s much l o w e r t h a n i n a c o m b i n a t i o n o f b o t h  In F i g . but  It will  decreases i n absolute  natural mortality increases.  of  mortality  a small f r a c t i o n .  Theoretical yield mortality Fig.  River white sturgeon, natural  a bigger  yield in  Where n a t u r a l m o r t a l i t y i s l o w , a l a r g e r number o f  fish  a y e a r c l a s s grows t o an o l d age and t h r o u g h g r o w t h a t t a i n s a  bigger weight.  Thus t h e l o s s i n number i s more t h a n c o m p e n s a t e d  for  i n w e i g h t o f t h e i n d i v i d u a l f i s h and t h u s t h e  by t h e g a i n  8000 I  FISHING Fig 21.  MORTALITY  Yield in weight at different rates of f i s h i n g and  RATE natural  mortality  63 whole stock.  I t i s obvious, therefore,  that i n s t o c k s , l i k e that  of the sturgeon, where n a t u r a l m o r t a l i t y i s low, greater y i e l d could be obtained i f f i s h i n g were delayed u n t i l the f i s h grew to an o l d age. In Table IX i s summarised the y i e l d at  different  combinations of f i s h i n g a n a t u r a l m o r t a l i t y .  Table IX  Y i e l d at d i f f e r e n t l e v e l s of f i s h i n g a n a t u r a l m o r t a l i t y u s i n g R i c k e r ' s method of estimating e q u i l i b r i u m y l e I d ( y i e l d in: u n i t s of weight)  Fishing Mortality  Maximum Y i e l d  Age  N a t u r a l M o r t a l i t y = 0.05 0.025 0.04 0.05 0.06 0.075 0.13 0.25  289 294 303 307 319 313 no maximum  25 23 19 19 16 11  130 157 172 182 209 233 no maximum  19 16 15 13 10 9  109 138 165 179 194 214 no maximum  15 15 13 12 10 9  26 24 21  N a t u r a l M o r t a l i t y = 0.089 0.025 0.04 0.05 0.06 0.075 0.13 0.25 N a t u r a l M o r t a l i t y - 0.10 0.025 0.04 0.05 0.06 0.075 0.13 0.25  15  64 I t i s e v i d e n t from t h i s t a b l e t h a t by i n c r e a s i n g the f i s h i n g m o r t a l i t y t h e r e i s an i n c r e a s e i n t h e y i e l d .  This  increase  i n y i e l d , however, i s not p r o p o r t i o n a l t o the i n c r e a s e i n t h e fishing mortality.  For example, by i n c r e a s i n g t h e  m o r t a l i t y from 0.06 t o 0.13 (53,837 0 increase)  fishing  the increase i n  r  y i e l d i s l e s s than 22%.  I t w i l l a l s o be noted t h a t w i t h i n c r e a s e d  f i s h i n g m o r t a l i t y t h e f i s h e r y b e g i n s t o u t i l i z e f i s h from t h e young age group w h i c h may l e a d t o t h e d e p l e t i o n of the s t o c k s . The food of the F r a s e r R i v e r w h i t e  sturgeons  R e s u l t s o f t h e e x a m i n a t i o n of the stomach c o n t e n t s of the F r a s e r R i v e r w h i t e s t u r g e o n show t h a t i t feeds on a wide range of food i t e m s .  Stomachs taken i n May show t h a t eulachons  formed the main i t e m of the d i e t d u r i n g t h i s p e r i o d .  The f a c t  t h a t most of t h e eulachons were p u t r i f y i n g i n d i c a t e s t h a t t h e s t u r g e o n i s a scavenger and feeds m a i n l y on t h e dead ones.  The  q u a n t i t y of eulachons t a k e n i s b i g , and fisherjnen s e l l i n g t h e i r c a t c h u n g u t t e d a t t h i s time l o s e two pounds on each f i s h w h i c h i s reckoned t o be  the w e i g h t of e u l a c h o n s i n t h e  stomachs, i  i  In a d d i t i o n to eulachons, s c u l p i n s , s t i c k l e b a c k s , lampreys and young s t u r g e o n were o b s e r v e d .  The o c c u r r e n c e of  young s t u r g e o n i n one of the stomachs needs more data b e f o r e we can c o n c l u d e t h a t i t i s h a b i t u a l f o r the w h i t e s t u r g e o n t o feed on i t s y o u n g .  I t i s p r o b a b l e t h a t t h e s e were swept i n t o t h e  mouth as t h e s t u r g e o n i n d i s c r i m i n a t e l y scooped t h e bottom f o r food.  Of the o t h e r t h r e e t y p e s of f i s h o b s e r v e d , t h e s c u l p i n s  were t h e most f r e q u e n t .  I t i s p r o b a b l e t h a t o t h e r types of  fish  65 a r e eaten but some of t h e stomach c o n t e n t s were so f a r t h a t p r o p e r i d e n t i f i c a t i o n c o u l d not be made.  digested  F i s h occurred i n  f o r t y - t h r e e o r 48.68? 0 of the stomachs t h a t had f o o d , but were more f r e q u e n t i n t h e b i g g e r  specimens.  Of the i n v e r t e b r a t e s e a t e n , Chironomid l a r v a e formed the biggest s i n g l e group.  They were r e c o r d e d i n t h i r t y - o n e  stomachs or 35.237 0 and were eaten by b o t h o l d and young f i s h . Crayfish,  s t o n e f l y l a r v a e and a few Ephemeroptera l a r v a e were  observed i n s e v e r a l stomachs.  C r a y f i s h were r e c o r d e d o n l y from  f i s h b i g g e r than 3 0 " , but the o t h e r two groups were e a t e n by f i s h of v a r i o u s s i z e s .  M y s i d s , Chaoborus l a r v a e , D a p h n i a , and  a few copepods were r e c o r d e d . Some green v e g e t a b l e m a t t e r and r o o t s of p l a n t s were recorded i n v a r y i n g q u a n t i t i e s .  A q u a t i c p l a n t s may be o c c a s i o n -  a l l y e a t e n , but i t i s l i k e l y t h a t t h e s e are t a k e n i n c i d e n t a l l y w i t h o t h e r food i t e m s . D e t r i t u s and p i e c e s of wood were p r e s e n t i n s e v e r a l stomachs.  W h i l e t h e s t u r g e o n may o b t a i n some n u t r i e n t s  from the d e t r i t u s , the p i e c e s of wood are j u s t one of  those  items i n c i d e n t a l l y taken w i t h f o o d . Harkness (1923) found t h a t Chironomidae l a r v a e ( m i l g e s ) , m o l l u s c s and Ephemeridae nymphs were the b a s i c s u p p l y of the l a k e s t u r g e o n i n N i p i g o n L a k e .  food  Trichoptera larvae  formed an i m p o r t a n t p a r t of t h e d i e t where t h e y o c c u r r e d i n g r e a t numbers.  Harkness observed t h a t i n some areas where o t h e r  organisms such as Decapoda, A n i s o p t e r a , and Amphipoda o c c u r r e d i n g r e a t numbers and were more e a s i l y o b t a i n a b l e the s t u r g e o n fed on t h e s e and t h e amount of t h e o t h e r w i s e s t a b l e d i e t became  66  practically negligible.  Harkness concluded that the sturgeon w i l l  take anything of food value that i t can f i n d , and that the more abundant and e a s i l y obtainable food w i l l come f i r s t of i t s nature.  regardless  F i s h , which form an important item i n the d i e t of  the Fraser R i v e r white sturgeon, formed only a minor part i n the food of the lake sturgeon i n Nipigon Lake. Probost and Cooper (1954) found Tendipedidae (Chironomidae) larvae to be the main food item i n the d i e t of the lake sturgeon i n Lake Winnibago, and noted that i n the smaller lakes mayflies and aquatic isopods were frequently taken.  Fish  were only o c c a s i o n a l l y recorded, and these appeared to be discarded b a i t minnows.  Thus, i n i t s feeding behaviour, the  Fraser River white sturgeon would appear to be more predaceous than the other two s p e c i e s .  F i s h eggs, though recorded, do hot  appear to form an important item of the d i e t , and i n some of the cases i t i s suspected that they were i n the ovaries of the eaten.  fish  67  DISCUSSION  Age for the Fraser River white sturgeon was determined from sections of the f i r s t p e c t o r a l f i n r a y s .  No experimental  evidence i s offered for the v a l i d i t y of t h i s method and i t s use was based on the c o n t r i b u t i o n s of other workers (Holzmayer 1924, Probost and Cooper 1954).  Age analyses revealed that the f i s h e r y  was most e f f e c t i v e between age groups nine to s i x t e e n and age group eleven, predominated the catches followed by age group thirteen.  There were only a few f i s h from the higher age groups.  The oldest f i s h i n the c o l l e c t i o n were females of s i x t y - t h r e e and seventy-one years of age.  The presence of these very old f i s h ,  and those that have been recorded by other workers, suggests that sturgeons as a group are long l i v e d , and that n a t u r a l m o r t a l i t y among the o l d f i s h at least i s rather low.  High f i s h i n g m o r t a l i t y  i s i n d i c a t e d by the predominance of young age groups i n the commercial catches. The a n a l y s i s of growth i n length of the Fraser R i v e r white sturgeon has shown that growth i s very v a r i a b l e . v a r i a b i l i t y i s e x h i b i t e d i n the growth of the i n d i v i d u a l  This fish  w i t h i n age groups, and i n the growth of the d i f f e r e n t year c l a s s e s . I t must, t h e r e f o r e , be a r e s u l t of a m u l t i p l i c i t y of factors which may i n c l u d e food, changes i n the environmental c o n d i t i o n s , and variations  i n the genetic characters i n v o l v i n g the physiology  and behaviour of the f i s h .  F i s h l i v i n g i n d i f f e r e n t parts of  68 the r i v e r w i l l feed on d i f f e r e n t items, and depending on the type and quantity of food a v a i l a b l e , random v a r i a t i o n s i n the growth r a t e s are l i k e l y to occur.  Bajkov (1951), Phyca (1956) and  Chadwick (1959), have studied the migration of the white sturgeon on the Columbia River and Sacremento River and present various distances covered by t h e . f i s h tagged.  Although there i s  apparently a seasonal pattern i n the m i g r a t i o n , Bajkov (op c i t ) , the v a r i a t i o n s i n the movement of i n d i v i d u a l f i s h are large enough to have f i s h end up i n d i f f e r e n t  l o c a l i t i e s where food  supply and other e c o l o g i c a l factors may be s u f f i c i e n t l y d i f f e r e n t to cause marked differences i n t h e i r growth r a t e s . A n a l y s i s of growth i n l e n g t h , both from e m p i r i c a l and back c a l c u l a t e d lengths, revealed no s i g n i f i c a n t differences i n the growth of the sexes up to age twenty.  A f t e r t h i s age,  c a l c u l a t e d lengths showed that the females grew f a s t e r .  The data  on e m p i r i c a l lengths i n older f i s h were not s u f f i c i e n t t o demonstrate any d i f f e r e n c e s . These data on the Fraser River white sturgeon i n d i c a t e that i t s growth i n l e n g t h i s i n agreement w i t h some other of sturgeon that have been s t u d i e d .  species  Probost and Cooper (1954),  working w i t h e m p i r i c a l l e n g t h , showed s i m i l a r v a r i a t i o n s i n the length of f i s h of the same age groups i n the lake sturgeon (Acipenser fulvescens) of Lakes Puygan, Winneconne and Bute des Morte, Wisconsin.  In t h e i r study they show v a r i a t i o n of 7.1 to  8.2" inches at age one; 32.0 to 44.0" at age t e n ; and 37.0 t o 56.0" at age f i f t e e n .  The s m a l l v a r i a t i o n at age one i s  obviously due to scanty data (they had only two specimens at age  6  one).  9  Sunde (1961) found the growth r a t e of the males and females  i n the l a k e s t u r g e o n  ( A c i p e n s e r f u l v e s c e n s ) o f the Nelson R i v e r v e r y  s i m i l a r up t o age t w e n t y , but at o l d e r ages the females grew much faster.  Classen  (1944) c i t e d i n P r o b o s t and Cooper (1954) found  a somewhat more r a p i d growth r a t e i n the females of A c i p e n s e r and C u e r r i e r (1949) found £he same i n A c i p e n s e r f u l v e s c e n s N o r t h e r n Quebec.  sturio  in  P r o b o s t and Cooper ( 1 9 5 4 ) , however, found no  evident differences  i n the growth of males and females of Lakes  Puygan, Winneconne and Bute de M o r t e . The curves  of growth o b t a i n e d by t h e two methods  employed i n s t u d y i n g growth of the F r a s e r a r e not v e r y d i f f e r e n t  River white  sturgeon  i n the male up t o age t w e n t y - f i v e .  After  age t w e n t y - f i v e e m p i r i c a l l e n g t h s appear t o be g r e a t e r than the calculated  lengths.  e m p i r i c a l lengths  In f e m a l e s the c u r v e determined  shows a r a t h e r marked i n f l e c t i o n p o i n t around  age t e n , and a s l i g h t o v e r - e s t i m a t i o n point.  of l e n g t h s around  A t ages h i g h e r than twenty y e a r s c a l c u l a t e d  appear t o be h i g h e r than the e m p i r i c a l l e n g t h s . these d i f f e r e n c e s  from  this  lengths  In b o t h cases  c o u l d be due t o the scanty d a t a at t h e s e o l d  a g e s , but c o u l d a l s o r e s u l t  from the f i s h i n g gear s e l e c t i n g  for  the slow g r o w i n g f i s h among the females and the f a s t growing f i s h among the m a l e s . (  i.  The d i f f e r e n c e ages has been a s c r i b e d  i n the w e i g h t s of the sexes at  t o the d i f f e r e n c e s  the gonads a t s e x u a l m a t u r i t y . s u b s t a n t i a t e t h i s argument  older  i n the enlargement  No d a t a were c o l l e c t e d  of  to  but one female ( t w e l v e f e e t l o n g and  825 pounds) caught from the F r a s e r R i v e r , had o v a r i e s  estimated  70 at 200 pounds i n weight, which i n d i c a t e s that the ovaries can grow to an immense s i z e . Compared w i t h the other species of sturgeons  that have  been s t u d i e d , the Fraser River female white sturgeon appears to reach sexual maturity at a much l a t e r age.  Roussow (1957) gives  the age at spawning maturity i n the d i f f e r e n t  species as f o l l o w s :  Species  Male  Female  Authority  A. fulvescens Rafinesque A . s t u r i o Linne A . guldenstadt Brandt A . b a k r i Brandt A . ruthens Linne Huso huso( Linne)  14 years 7-9 8-14 10 - 12 3-7 12 - 14  23 years 8-14 13-20 12-14 5-12 16 - 18  Cuerrier Chalikov Lukin Kozhin Lukin Chalikov  (1949) (1949) (1949) (1949) (1949) (1949)  Phyca (1956) mentioned that a v a i l a b l e evidence on the Columbia River white sturgeon suggested that the females d i d not probably mature before eleven to twelve years.  Age at m a t u r i t y ,  i n the Columbia R i v e r female white sturgeon appears to be r a t h e r low.  However, Sunde (1961) has shown that w i t h i n the same species  sexual maturity i s reached at d i f f e r e n t ages i n d i f f e r e n t  regions.  Spawning i n the Fraser R i v e r white sturgeon occurs at i n t e r v a l s of f i v e to ten or more years.  Whether there i s any difference between  the reproductive c y c l e i n the sexes i s not c l e a r l y i n d i c a t e d by the a v a i l a b l e data.  C u e r r i e r (1949) c i t e d i n Harkness and  Dymond (1961), stated that the male sturgeon of the S t . Lawrence R i v e r spawned twice as often as the female — the male spawning every two to three years and the female every three to f i v e years. Late spawning m a t u r i t y , and extended i n t e r v a l s between spawning, pose an important problem i n the management of sturgeon  s t o c k s . Sturgeons must grow to a large s i z e before they s t a r t to spawn, and where they share waters w i t h some other commercially e x p l o i t e d species i t i s i n e v i t a b l e that a s u b s t a n t i a l number of sturgeons i s caught before the f i s h reach spawning stage.  In any  year c l a s s t h i s g r e a t l y reduces the number of f i s h that l i v e to a spawning stage, and since spawning i s not frequent a stage i s reached when recruitment can no longer balance the losses through n a t u r a l m o r t a l i t y and c a t c h .  There i s no doubt that these f a c t o r s  coupled w i t h i n t e n s i v e f i s h i n g , have played an important part i n the c a t a s t r o p h i c d e c l i n e i n a l l the sturgeon stocks that have been e x p l o i t e d . Y i e l d curves under d i f f e r e n t combinations of f i s h i n g and n a t u r a l m o r t a l i t y have been presented showing l e v e l s of f i s h i n g m o r t a l i t y at which maximum y i e l d s are obtained.  These  curves r e v e a l that highest y i e l d i n absolute value are obtained i n conditions of only a low n a t u r a l m o r t a l i t y .  Under these  c o n d i t i o n s a r e l a t i v e l y low f i s h i n g m o r t a l i t y r a t e i s necessary i n order to maximize y i e l d , and i t i s b e n e f i c i a l to postpone f i s h i n g u n t i l the f i s h reach an old age.  Increasing the f i s h i n g  m o r t a l i t y r a t e depletes the old age groups and the f i s h e r y begins to operate on young age groups.  Since the f i s h taken then are  of less weight, i n order to maintain the y i e l d at a high l e v e l i t i s necessary to f i s h more.  However, the more the f i s h i n g  m o r t a l i t y r a t e i s increased, the lower the age at recruitment becomes, and t h i s may reach a stage at which f i s h are caught before they have reached spawning stage.  This g r e a t l y a f f e c t s  the s i z e of the spawning stock, and leads to d e p l e t i o n of s t o c k s .  72 Curve B i n F i g . 21, where n a t u r a l m o r t a l i t y i s s t a b i l i z e d at 0.089, depicts the present state i n the Fraser River white sturgeon.  This curve shows that a maximum y i e l d  would be obtained at a f i s h i n g m o r t a l i t y r a t e of 0.065 which i s 50% lower than the present r a t e .  At the present  fishing  m o r t a l i t y rate, f i s h become f u l l y vulnerable to the f i s h i n g gear when they are eleven years o l d ; whereas at a f i s h i n g m o r t a l i t y r a t e of 0.065 t h i s age would be s h i f t e d up t o about s i x t e e n years. From these findings i t can be concluded that the present f i s h i n g m o r t a l i t y r a t e i n the Fraser River white sturgeon i s too high and the f i s h e r y has reached a stage where i t must operate on young ages i n order to maximize y i e l d .  Whether t h i s  y i e l d can be sustained year a f t e r year depends on the nature of recruitment to the f i s h e r y .  It has been observed that i n the  Fraser River white sturgeon the males do not spawn u n t i l they reach age eleven, and that the females may not spawn u n t i l they are twenty-five to twenty-seven years o l d .  Thus, i f  full  recruitment takes place at age eleven and any r e c r u i t e d year c l a s s remains i n the f i s h e r y for a period of s i x t e e n years  after  age eleven, the females would j u s t have reached sexual maturity at the end of t h e i r i l i f e expectancy (twenty-seven years of age under the present conditions of n a t u r a l and f i s h i n g m o r t a l i t i e s ) . In the post-recruitment phase any year class i s reduced i n number through both n a t u r a l and f i s h i n g m o r t a l i t y .  By the time they  reach sexual maturity the females would therefore have been g r e a t l y reduced, and since a l l females do not spawn at the same age, i t i s most l i k e l y that future recruitment w i l l be affected  73 by the very small s i z e of the spawning stock.  Sunde (1961)  analysed the strength of the d i f f e r e n t year classes i n Nelson R i v e r lake sturgeon and found that low number of r e c r u i t s r e s u l t e d from years of i n t e n s i v e f i s h i n g which suggested that recruitment was d i r e c t l y r e l a t e d to the s i z e of spawning stock.  It i s  obvious therefore that w i t h t h i s i n t e n s i v e f i s h i n g on the Fraser R i v e r , there has been a progressive lowering of the age at recruitment which w i l l u l t i m a t e l y r e s u l t i n complete d e s t r u c t i o n of the s t o c k s .  74  .  MANAGEMENT  . For a r a t i o n a l e x p l o i t a t i o n of a f i s h e r y , i t i s necessary that the loss from the f i s h e r y through n a t u r a l and f i s h i n g m o r t a l i t y be counter-balanced by the a d d i t i o n to i t through growth and recruitment.  The present study on the  Fraser River white sturgeon has revealed that the present f i s h i n g m o r t a l i t y r a t e i s too high and that most of the are being caught before they have spawned.  fish  Under these  conditions not enough f i s h l i v e to spawning stage and there i s l i k e l y to be d e p l e t i o n of stocks through progressive reduction of the  spawners. The d e p l e t i o n of the stocks i n the Fraser River white  sturgeon has i n fact already been observed.  Rodd (1926) c i t e d  i n Sunde (1961) reported a reduction of 93.3% i n the production on the Fraser River between 1897 and 1905, a period which immediately followed the beginning of the f i s h e r y .  This d e c l i n e  however, was i n part due to the removal of the accumulated n a t u r a l stocks as has been observed i n other stocks where a -  i  f i s h e r y has been introduced for the f i r s t time (Ricker 1963). Clemens and Wilby (1949) hinted that large specimens were r a r e l y taken and that the species was i n danger of (commercial) •extermination. The d e p l e t i o n of sturgeon stocks through o v e r - f i s h i n g , however, i s not p e c u l i a r to the Fraser River s t o c k s , but has been  reported from many other areas i n North America, Europe, and Asia.  Evermann and Latimer (1910) stated that when commercial  f i s h i n g started i n the Lake of the Woods i n 1884, the lake was the greatest sturgeon pond i n the w o r l d .  In the l a s t decade of  that century over 7.5 m i l l i o n pounds of sturgeon were taken. In the forty-seven years f o l l o w i n g 1900, less than a m i l l i o n pounds were obtained of which only 25,000 pounds were taken after 1920.  This d e c l i n e i n the sturgeon population prompted i t s  p r o t e c t i o n i n t h i s lake as from 1941.  Evermann and Latimer  (1910) stated that the v i r t u a l disappearance of the sturgeon from the Lake of the Woods was without doubt c h i e f l y due to over-fishing.  Van Oosten (1937, 1939) r e f e r r i n g to the Great  Lakes f i s h e r i e s , stated that the lake sturgeon, once considered a nuisance because of i t s abundance, has now become a museum c u r i o s i t y , and i n the 1939 paper pointed out that the disappearance of t h i s species was due to sheer wanton destruction.  Phyca (1956) reported that heavy commercial  f i s h i n g led to the d e p l e t i o n of the sturgeon i n the C a l i f o r n i a waters by 1900 though they had been abundant enough to have been considered a nuisance.  Sunde (1961) states that the high  r a t e of e x p l o i t a t i o n i n the Manitoba sturgeon a f t e r 1900 r e s u l t e d i n the d e p l e t i o n of the stocks which prompted the c l o s u r e of the f i s h e r y i n 1910.  Sunde reports that i n the Nelson  R i v e r where e x p l o i t a t i o n f i r s t began i n 1907 the production f e l l d r a s t i c a l l y by 1927 due to d e p l e t i o n of the s t o c k s .  This  r e s u l t e d i n the closure of the f i s h e r y i n 1929. In a l l the areas where the d e p l e t i o n has been detected measures have been taken to protect the s t o c k s .  These ^measures  76 have taken various forms i n d i f f e r e n t areas and i n some places a combination of more than one conservation technique has been employed.  These have i n c l u d e d :  1.  P r o h i b i t i o n of d e s t r u c t i v e f i s h i n g methods.  2.  Licensing.  (Whereby only a l i m i t e d number of persons  could be permitted to f i s h for sturgeon.) 3.  Size l i m i t .  Various s i z e s have been set at which the  f i s h could be l e g a l l y caught, and fishermen have been required to return to the water a l l under-sized f i s h caught.  This i s  under the assumption that at those set various s i z e s the would have spawned.  fish  However, evidence from various sources has  proven that most of these s i z e l i m i t s have been too l i b e r a l and most f i s h have been caught before spawning. 4.  Closed seasons.  This has taken two forms: a) c l o s i n g  the f i s h e r y f o r a short period to protect the spawning f i s h or to l i m i t the amount of f i s h caught; and b) c l o s i n g the f i s h e r y for a long period of time to allow the stocks to b u i l d up. Several f i s h e r i e s have been closed down completely, but not much success has been achieved.  Harkness and Dymond  (1961) noted that a ten-year c l o s u r e i n Lake N i p i s s i n g , O n t a r i o , and i n Manitoba showed no evidence of improvement of sturgeon stocks.  In Michigan where the f i s h e r y was closed for twenty-one  y e a r s , there was no apparent effect on the production.  Evidence  from the l i f e h i s t o r y of the sturgeon i n d i c a t e s that a prolonged c l o s u r e of the f i s h e r i e s would cause only a temporary r e v i v a l of the stocks that have been depleted. I t i s evident t h e r e f o r e , that these r e g u l a t i o n s have  77  not been r i g i d enough to protect the sturgeon s t o c k s .  More  r e s t r i c t i v e measures are necessary to protect the yet e x i s t i n g stocks.  The very slow growth rate does not permit a replacement  r a p i d enough to keep pace w i t h the annual catch. On the Fraser River a 36" s i z e l i m i t has e x i s t e d for a long time, and the catch i n the g i l l nets has been g r e a t l y regulated by the closed f i s h i n g seasons pertinent to the salmon fishery.  The s e t - l i n e f i s h e r y has a l s o been p r o h i b i t e d as f a r  back as 1928, although i t i s apparent that t h i s r u l i n g has not been s t r i c t l y adhered t o .  Though catch s t a t i s t i c s show that the  production has been maintained for a rather long p e r i o d of time, i t has f l u c t u a t e d at a very low l e v e l .  The age composition of  the catch reveals that the f i s h e r y has reached a stage where the s i z e of the spawners has been so g r e a t l y reduced that recruitment i s l i k e l y to be a f f e c t e d .  Normally an  future  instantaneous  f i s h i n g m o r t a l i t y of 0.130 would not be considered excessive but since the sturgeon i s a l o n g - l i v e d f i s h , the f i s h i n g m o r t a l i t y exerted over the long e x p l o i t e d phase of the f i s h ' s l i f e b u i l d s up to some s u b s t a n t i a l v a l u e .  Ricker (1963) has demonstrated  the  marked or even catastrophic effects which r e s u l t from small causes i n t h i s kind of s i t u a t i o n , and has shown that i n a population which includes upwards of twelve to f i f t e e n age groups  before  e x p l o i t a t i o n , even as l i t t l e as 5% catch per annum e v e n t u a l l y causes a major reduction i n the r e l a t i v e weight of the older f i s h i n the stock.  78  SUGGESTIONS FOR FUTURE MANAGEMENT  For the slow growth and delayed sexual m a t u r i t y , the sturgeon needs conservation measures which would protect not only the young f i s h but a l s o the spawning stocks.  The i n c i d e n t a l  nature of the sturgeon f i s h e r y on the Fraser R i v e r makes r e g u l a t i o n s based on s i z e l i m i t rather d i f f i c u l t s i z e i s governed by the salmon f i s h e r y .  for the mesh  However, the fact that  the f i s h e r y has been maintained, even at t h i s low l e v e l , f o r a long time suggests that there has been a c e r t a i n amount of escapement of sturgeon which have l i v e d to a spawning age. To maintain the e x i s t i n g s t o c k s , i t i s thus evident that s t r i c t p r o t e c t i o n should be afforded t o the f i s h that escape the g i l l net f i s h e r y .  To accomplish t h i s i t w i l l be  necessary to completely p r o h i b i t the s e t - l i n e f i s h e r y . Observations on the reproductive biology of the sturgeon have i n d i c a t e d that egg production increases as the f i s h grow o l d e r . This means that i f the escaping f i s h are allowed to l i v e longer, the future recruitment i s l i k e l y to be l a r g e r .  This study has  shown that under the p r e v a i l i n g m o r t a l i t y rates most of the disappear from the f i s h e r y at age twenty-seven.  fish  At t h i s age  the e a r l y female spawners would have spawned only once and the amount of spawn would not be l a r g e .  Assuming that the s u r v i v a l  r a t e among the eggs and the young f i s h remains the same, p r o t e c t i o n of the spawners should be able not only to maintain  79  the stocks but a l s o cause an increase i n the y i e l d due to I increase i n recruitment. This study has revealed that the present  fishing  m o r t a l i t y r a t e i n the Fraser River white sturgeon exceeds the l e v e l at which y i e l d could be maximized, and that i t i s now operating on young age groups. i n the f i s h i n g .  This would c a l l for a reduction  T h i s , however, i s not d i r e c t l y p o s s i b l e on  the Fraser River where the f i s h i n g species of f i s h .  e f f o r t i s d i r e c t e d on other  An i n d i r e c t way of doing i t would be to  change the s i z e l i m i t at which the f i s h are taken and step i t up to 48" fork l e n g t h .  At t h i s length the f i s h would on the  average have reached twenty years of age. not have a t t a i n e d sexual  The females would  maturity at t h i s age, but most of  them would have spawned at least once before the end of the e x p l o i t a t i o n phase.  This measure would involve only a change  i n the mesh s i z e i f the sturgeon were the only commercially important species on the Fraser R i v e r .  On the Fraser R i v e r ,  many other s p e c i e s , for example, sockeye, are e x p l o i t e d and these require a much smaller mesh s i z e than would be needed of a sturgeon that has a t t a i n e d a length of 48" i n fork length. I t i s therefore impossible i n p r a c t i c e to avoid c a t c h i n g . sturgeon before they a t t a i n 48". Though r e g u l a t i o n s r e q u i r i n g fishermen to r e t u r n to the water a l l f i s h under a set length can be introduced, the fact that a l o t of f i s h would be k i l l e d cannot be overlooked. Most of  the sturgeon examined from the commercial  catch f e l l below 48" fork l e n g t h .  I f the fishermen were to  80 r e t u r n a l l f i s h below t h i s l e n g t h t o the w a t e r i t w o u l d d e p r i v e them of an income from the  s a l e of s t u r g e o n , w h i c h p r o b a b l y  compensates f o r t h e damage done t o the n e t s . t h a t the p r e s e n t 36" s i z e  It is  l i m i t be m a i n t a i n e d as the minimum  l e n g t h a t - w h i c h s t u r g e o n s may be t a k e n , and a 48" length)  size  l i m i t be e s t a b l i s h e d  may be t a k e n .  suggested  (=54* t o t a l  beyond w h i c h no s t u r g e o n  T h i s s h o u l d o f f e r p r o t e c t i o n t o the young f i s h  /as w e l l as the spawning s t o c k .  I t i s apparent t h a t o n l y a  s m a l l number of s t u r g e o n beyond 48" w i l l be c a u g h t ,  and t h e i r  r e t u r n t o t h e w a t e r s h o u l d not cause much r e p e r c u s s i o n  among  the fishermen. Breeding places f o r the Fraser R i v e r white were not i n v e s t i g a t e d  during t h i s study.  sturgeon  However, o t h e r  w o r k e r s have i n d i c a t e d t h a t the s t u r g e o n spawns i n f a s t water near r a p i d s  or w a t e r f a l l s .  t h a t on the F r a s e r , Langley to Y a l e . of the s e t - l i n e  I t would t h e r e f o r e  appear  spawning p l a c e s might o c c u r anywhere beyond  I t i s i n t h i s a r e a t o o , where the p r o h i b i t i o n f i s h e r y has been g r e a t l y v i o l a t e d and where  the odd b i g ones have been most f r e q u e n t l y t a k e n .  It  is  t h e r e f o r e suggested t h a t s t u r g e o n f i s h i n g i n t h i s a r e a be completely abolished.  In t h i s a r e a o n l y those  licensed  c o m m e r c i a l f i s h e r m e n o p e r a t i n g a gear i n w h i c h i t i s  inevitable  t o c a t c h s t u r g e o n may r e t a i n f i s h t h a t conform t o t h e 36" t o 54"  limit. No d a t a were c o l l e c t e d on t h e s t u r g e o n s p o r t  on the F r a s e r R i v e r . sport  fishery  H c w e v e r , i t i s known t h a t a l a r g e number of  f i s h e r m e n a r e engaged i n t h i s f i s h e r y and no doubt many  sturgeons are caught.  The e f f e c t  of t h i s f i s h e r y on the  sturgeon  p o p u l a t i o n would have t o be c o n s i d e r e d i n any management scheme.  81  SUMMARY  The growth of the Fraser River white sturgeon was studied from data c o l l e c t e d from the fishermen's catch i n the lower part of the Fraser R i v e r , and a few specimens g i l l - n e t t e d at Dewdney Slough near Mission C i t y , B r i t i s h Columbia.  Age was  determined for 230 specimens from c r o s s - s e c t i o n s of the f i r s t pectoral f i n rays.  A p r e l i m i n a r y study was made to determine  the region of the p e c t o r a l f i n ray from which a consistent number of r i n g s could be obtained.  This was found to be an  area %" away from the base of the f i n ray i n f i s h over 20" long. I f sections were taken at a distance f a r t h e r than %", there was a l i k e l i h o o d of underestimating age due to loss of a n n u l i , and i f taken too near the base of the f i n r a y , sections were d i f f i c u l t t o read. Growth i n length was studied by two methods: by averaging the lengths of f i s h of the same age groups and r e l a t i n g t h i s to age; and by back c a l c u l a t i n g growth at the d i f f e r e n t ages from the cross s e c t i o n of the f i r s t p e c t o r a l f i n r a y .  For the  back c a l c u l a t i o n method i t was necessary f i r s t to f i n d the r e l a t i o n s h i p between growth i n length of the f i s h and the growth of the f i r s t p e c t o r a l f i n r a y .  This r e l a t i o n s h i p was found to  be l i n e a r and represented by the equation y = 0.9 + 9.5x when the r a d i a l lengths of the f i n ray sections were taken from the centre along the point of curvature of the r i n g s to the  82 periphery of the cross s e c t i o n , and by the equation y = -3.1 + 10.2x i f the measurements were taken along a s t r a i g h t  l i n e from  the centre to the same point on the periphery of the cross section.  Both these l i n e s had the same c o r r e l a t i o n c o - e f f i c i e n t  but the f i r s t equation was favoured for back c a l c u l a t i o n of growth because i t had a s l i g h t l y lower standard d e v i a t i o n from a r e g r e s s i o n l i n e f i t t e d by the method of least  squares.  Growth curves constructed from data obtained by both methods showed s i m i l a r growth i n both sexes up to age twenty (using back c a l c u l a t e d l e n g t h ) . grew faster than the males. t o a fixed maximum s i z e .  A f t e r t h i s age, the females  However, neither sex seemed to grow  A n a l y s i s of growth of the  different  year classes revealed differences i n the growth r a t e s . year c l a s s e s had a slower growth r a t e .  Some  Differences i n the growth  r a t e of d i f f e r e n t year classes were a l s o evident from the study of the instantaneous  growth rates i n r e l a t i o n . t o s i z e .  While  these differences could not be r e l a t e d to changes i n the feeding behaviour of the f i s h , i t was suggested that they might be due to random migrations w i t h i n the r i v e r because d i f f e r e n t areas i n the r i v e r apparently present d i f f e r e n t o p p o r t u n i t i e s for growth.  Due to scanty data, analyses of growth i n the  calendar years d i d not r e v e a l d e f i n i t e  different  trends.  Growth i n weight was studied by two methods.  One was  by averaging the weight of the d i f f e r e n t age groups and r e l a t i n g them to ages.  This method showed that growth i n weight i n both  sexes was s i m i l a r up to age f i f t e e n . Growth was c h a r a c t e r i z e d by very low increments i n weight up to age s i x to seven, but  83 increased  u n i f o r m l y up t o age  fifteen.  A f t e r age f i f t e e n  were s c a n t y and no comparison c o u l d be made. was by c a l c u l a t i n g w e i g h t s at d i f f e r e n t weight r e l a t i o n s h i p .  The second method  lengths using a length/  The l e n g t h / w e i g h t r e l a t i o n s h i p was  o b t a i n e d by p l o t t i n g the l o g a r i t h m s logarithms  of w e i g h t a g a i n s t  of l e n g t h and f i t t i n g r e g r e s s i o n  The e q u a t i o n s o b t a i n e d  were:  Log W = - 8 . 7 3  + 3.13 Log L  f o r males  Log e W = - 8 . 7 9  + 3.15 L o g e L  f o r females  but at  lengths.  the  l i n e s t o the d a t a .  These e q u a t i o n s were used t o c a l c u l a t e various  the d a t a  the weights  B o t h sexes showed s i m i l a r growth up t o  l e n g t h s g r e a t e r than t h i s the females were  at  30",  heavier.  The age at s e x u a l m a t u r i t y was s t u d i e d from the e x a m i n a t i o n of the f i n r a y s e c t i o n s f o r p e r i o d s growth.  of  retarded  I t was found t h a t some males become s e x u a l l y  mature  at age e l e v e n but females do not mature u n t i l they a t t a i n t w e n t y - f i v e to twenty-seven y e a r s .  age  A l l f i s h i n b o t h sexes do  not r e a c h s e x u a l m a t u r i t y at the same t i m e .  There a r e  big  i n t e r v a l s between spawningswhich may extend from f i v e t o t e n y e a r s o r even  longer.  The t o t a l a r i t h m e t i c m o r t a l i t y r a t e between ages e l e v e n t o twenty-seven was found t o be 0.197  as  determined  from t h e c a t c h c u r v e .  However, i t was assumed t h a t i n u n f i s h e d  c o n d i t i o n the sturgeon  c o u l d l i v e t o age f i f t y and from t h i s  assumption  an i n s t a n t a n e o u s n a t u r a l r a t e of 0.089 and an  i n s t a n t a n e o u s f i s h i n g m o r t a l i t y r a t e of 0.130 were  calculated.  84 From y i e l d computations i t was found that t h i s  instantaneous  f i s h i n g m o r t a l i t y r a t e i s excessive and as a r e s u l t the f i s h e r y i s now u t i l i s i n g f i s h from the younger age groups.  Such a  s i t u a t i o n could lead to the d e p l e t i o n of the sturgeon stocks through a reduction of the spawning stocks.  Due to the i n c i d e n t a l  nature of the white sturgeon f i s h e r y on the Fraser R i v e r , i t i s not p r a c t i c a l to reduce the magnitude of f i s h i n g without i n t e r f e r i n g w i t h the other more important f i s h e r i e s on the r i v e r . The best way to protect the sturgeon on the Fraser River i s through p r o t e c t i n g the spawning s t o c k s .  It i s therefore suggested that  the present 36" minimum s i z e l i m i t be maintained and that a 54" maximum s i z e l i m i t be introduced so that no sturgeons  l a r g e r or  i i  smaller than t h i s range be taken.  It i s a l s o suggested that the  s e t - l i n e f i s h e r y be completely abolished and that f i s h i n g for sturgeon be p r o h i b i t e d i n the area between Langley and Y a l e , t h i s being the most l i k e l y r e g i o n i n the lower Fraser R i v e r where sturgeons spawn.  85  LITERATURE CITED  B a j k o v , A . D. (1949) A p r e l i m i n a r y r e p o r t on the Columbia River white sturgeon. O r e . F i s h . Comm. Re. B r i e f s 2 ( 2 ) : 3-10. '  (1951) M i g r a t i o n of the w h i t e s t u r g e o n ( A c i p e n s e r transmontanus) on t h e Columbia R i v e r . O r e . F i s h . Comm. Res. 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Roussow, George (1957) Some considerations concerning sturgeon spawning p e r i o d i c i t y . J . F i s h Res. Bd. Canada 14(4): 553-572. Schneberger, E . , and L . A . Woodbury (1944) The lake sturgeon (Acipenser fulvescens Refinesque) i n Lake Winnebago, Wisconsin. Trans. Wise. Acad. S c i . and L e t t e r s . 36:131-140. Smith, H. M. (1914) The passing of the sturgeon. Rept. U . S . Comm. F i s h . 1913. Doc.782, Govern. P r i n t , o f f i c e , Washington. 78 pp. Sunde, L . A . (1961) Growth and reproduction of the lake sturgeon (Acipenser fulvescens rafinesque)of the Nelson R i v e r i n Manitoba. Unpubl. M. Sc. Thesis. U n i v e r s i t y of B r i t i s h Columbia, i-ix+93 pp. Tower, W. S. (1909) The passing of the sturgeon: a case of u n p a r a l l e l e d extermination of a species. Pop. S c i . Mo. 73:361-371. Van Oosten, J . (1936) The Great Lakes F i s h e r i e s : t h e i r proper management for sustained y i e l d . Trans. Amer. F i s h . Soc. 66: 131-138. ;  (1939) Can the Great Lakes be saved? W i l d l . May - June 1939: 130-135.  Amer.  APPENDIX I ANALYSIS OF STOMACH CONTENTS  Date  SN  Length  Fish  Chironomids  1.5.62  178 182  32.5" 37.0  Eu lachons Eulachons  8.5.62  150 160 161 162 163 170 175  48.5 33.0 32.0 35.0 33.5 32.5 35.0  Eulachons Eulachons Eulachons Eulachons Eulachons Eulachons Eulachons  15.5.62  155 165 169  40.0 51.0 34.0  Eulachons Eulachons Eulachons  29.5.62  89 90  41.0 31.5  Eulachons ( f u l l Eulachons  5.6.62  91 92 93 94  47.0 36.0 50.0 32.5  remains a few remains a few skeleton Eulachons (% lb)  14.6.62  102 108 109  55.0 33.0 34.0  a sculpin remains  Crayfish  Molluscs  Other Inv  Other Items  a few remains  stomach) a few s h e l l s  a few remains a few remains  spruce cone;  Date  SN  Length  19.6.62  110  33.0'  26.6.62  111 112  44.0 37.5  4 sculpins (125 gm) remains (30 gm)  113 114  38.0 31.0  skeleton  116  29.0  a few  117 118  24.0 21.5  2 Odonata larvae  a few  119 120 121  19.0 20.5 15.0  2 Stonefly larvae  122 123  16.0 11.0  a few  124  13.0  1 gram  125  51.5  skeleton  126 127  41.5 36.0  4 young sturgeons  128 129 130  34.5 36.0 45.5  3.7.62  4.7.62  Fish  Chironomids  Crayfish  Molluscs  a few remains  Other Inv  Other Items  1 stonefly larva  a few remains a few remains  14 gm green vegetable matter Sand. 4 pieces wood  1 stickleback  a few Ephemeroptera larvae c a d d i s f l y cocoons 4 stonefly larvae Detritus 2 stonefly larvae Detritus  a few  remains (28 gm) 1 s c u l p i n (20 gm)  Green veg. matter Wood Detritus  a few remains  Pieces of wood Sand Pieces of wood Sand  co  so  Date  SN  Length  10.7.62  134 135  33.5" 32.5  136  32.0  17.7.62  137 138  34.0 36.5  18.7.62  139 140 142 143  62.0 51.0 34.0 31.5  144  32.0  145  38.0  182 183 184 185 186 188  37.0 45.5 45.5 37.0 27.0  189  36.0  190  34.5  24.7.62  25.7.62  Fish  Chironomids  Crayfish  Molluscs shells  rather plentiful a few remains  Other Inv  Other Items Pieces of wood Vegetable matter  a few 6 gm  a few remains  6 gm  a few remains 6 gm remains a few remains  Pieces of wood  34 gm 1 gm  1 s c u l p i n 4 gm Pieces of wood  vo o  SN  Length  2.8.62  192 193 194  12.0" 15.5 29.0  195 196 197  25.0 15.0 22.0  198  18.5  199 200  22.5 19.5  201 202  18.5 15.5  203 204  14.0 9.5  2 a few  205  9.0  25% of a l l contents  206 207  8.5 9.5  18.5  Crayfish  Molluscs  Other Inv  a few  Largest single group  a few  Other items  Pieces of wood a few s h e l l s Mysids 1 stonefly larva Mysids 20  Detritus plentiful Detritus plentiful Detritus, •vegetable matter, f i s h eggs, pieces of wood  Remains 40% of contents  Detritus plentiful  A few remains plentiful 2 gm  208 209  Fish  Chironomids  Date  a few  1 stonefly larva 1 Mysid  A few Copepods 2 Mysids few s h e l l s a few s h e l l s  Detritus Wood, f i s h eggs, Detritus Detritus Small amount of veg matter Vegetable matter: biggest group  Date  SN  Length  2.8.62  211 212  14.5 14.0  213  15.0  215  12.0  216 217  12.0 13.0  30  218  13.0  a few  227 228  36.0 33.0  1 sculpin a few  222  34.0  1 stickleback  223  34.5  10  224  33.5  a few  225  34.0  226  37.0  227  36.0  228  33.0  16.8.62  Fish  Chironotnids  a few remains a few remains  a few  Crayfish  Molluscs  10  1 sculpin  30 a few  Other Items  Mysids 5 A. few Mysids  Wood, eggs Eggs, sand, pieces of wood  Mysids 30 Chaoborus 5 Cyclops a few  20  a few  Other Inv  Mysids 60?  o  Stonefly larva 1 a few a few remains  a few remains  Stonefly larva 1 Stonefly larva 1  Stonefly larva 1 Stonefly larva 1  Detritus plentiful  Pieces of wood Pieces of wood, green veg matter Green vegetable matter Detritus roots  Pieces of wood Pebbles  Date  SN  Length  Fish  21.8.62  229 230 231  42.0" 41.0 31.0  1 sculpin  25.8.62  232  32.0  4.10.62  246  34.0  248  33.0  251  33.5  5.10.62  Chironomids  plentiful  Crayfish  Molluscs  Other Iny  a few Chaoborus larvae  Other Items  Sand  a few  Pieces of wood  20  Sand, pieces of wood  1 lamprey  94 APPENDIX I I  In the work s h e e t s p r e s e n t e d i n Appendix I I , column 1 r e f e r s t o the age o f the f i s h .  Column 2 r e f e r s t o the average  l e n g t h of the f i s h at the d i f f e r e n t w e i g h t of f i s h at d i f f e r e n t weight r e l a t i o n s h i p .  ages.  Column 3 g i v e s  ages as computed from the  the  length/  Column 4 r e p r e s e n t s the i n s t a n t a n e o u s  r a t e o f growth and i s o b t a i n e d by t a k i n g the d i f f e r e n c e t h e n a t u r a l l o g a r i t h m s of two a d j a c e n t y e a r s .  of  Columns 5 and  6 r e p r e s e n t the i n s t a n t a n e o u s r a t e s o f n a t u r a l and f i s h i n g mortality.  Column 7 i s the r e s u l t a n t  the d i f f e r e n c e  growth.  It  between growth and the components  m o r t a l i t y , g - (p+q).  The weight f a c t o r  represents of  i n column 8 i s  o b t a i n e d f o r the v a r i o u s ages by r a i s i n g e t o power shown at t h e c o r r e s p o n d i n g age i n column 7. of the s t o c k .  Column 9 g i v e s t h e weight  In a l l t h e s e computations  i t i s assumed t h a t  1000 weight u n i t s a r e r e c r u i t e d t o t h e f i s h a b l e i n advance o f the f i s h i n g . first  fishable  The weight o f the s t o c k i n the  year i s therefore  by the w e i g h t change f a c t o r  stock a year  o b t a i n e d by m u l t i p l y i n g 1000  i n t h a t y e a r , and f o r  the  subsequent y e a r s by m u l t i p l y i n g the weight change f a c t o r t h e weight of the s t o c k i n the p r e c e d i n g y e a r .  The average  w e i g h t o f the s t o c k i n column 10 i s the mean weight o f s t o c k i n two a d j a c e n t y e a r s .  by  the  Column 11 g i v e s the y i e l d from a  s t o c k i n a f i s h i n g p e r i o d and i s o b t a i n e d by m u l t i p l y i n g the average w e i g h t of the s t o c k by the i n s t a n t a n e o u s r a t e of mortality.  fishing  The t o t a l f o r column 11 g i v e s the t o t a l y i e l d from a  r e c r u i t d u r i n g the p e r i o d i t i s i n the  fishery.  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  .154 9.0 12.1 .390 14.2 .650 17.0 1.24 19.5 1.77 21.7 2.46 24.1 3,36 26.0 4.10 28.3 5.70 30.6 7.25 33.9 10.1 35.0 11.1 13.2 37.0 15.6 39.0 40.8 18.0 21.2 42.9 44.8 24.2 46.5 27.1 48.0 30.0 50.0 34.1 51.6 37.8 53.2 41.7 46.1 54.9 56.6 50.4 58.2 55.2 60.0 61.0 61.5 65.4 70.8 63.0 64.2 75.2 65.5 79.9 66.7 84.8 68.0 90.1 69.2 95.6 70.6 101.0 71.7 106.0  £-(v+a) K y 4 ;  AvW  s  - -Change Wt. of Ay. Wt. , Factor Stock of Stock w t  Yield  1000 .44 .05 .33 .05 .31 .05 .20 -.05 .33 .05 .24 .05 .33 .05 .10 .05 .17 .05 .17 .05 .14 .05 .16 .05 .14 .05 .11 .05 .10 .05 .13 .05 .10 .05 .10 .05 .10 .05 .09 .05 .09 .05 .11 .05 .07 .05 .08 .05 .06 .05 .06 .05 .06 .05 .06 .05 .06 .05 .05 .05 .05 .05 .05 .05  .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025  .365 .255 .235 .125 .255 .165 .255 .025 .095 .095 .065 .085 .065 .035 .025 .055 .025 .025 .025 .015 .015 .035 -.005 + .005 -.015 -.015 -.015 -.015 -.015 -.025 -.025 -.025  1.448 1.297 1.278 1.939 1.297 1.1851.297 1.031 1.105 1.105 1.073 1.094 1.073 1.041 1.031 1.062 1.031 1.031 1.031 1.020 1.020 1.041 0.990 1.010 0.980 0.980 0.980 0.980 0.980 0.970 0.970 0.970  1448 1878 2387 2719 3527 4179 5420 5588 6175 6823 7321 8009 8594 8946 9223 9795 10099 10412 10735 10950 11169 11627 11511 11626 11393 11165 10942 10723 10508 10193 9887 9590  1679 2133 2553 3123 3853 4800 5504 5882 6499 7072 7665 8302 8770 9085 9509 9947 10255 10514 10843 11080 11398 11569 11569 11510 11279 11054 10833 10616 10351 10040 9739  41.98 53.33 63.82 78.08 96.33 120.00 137.60 147.05 162.48 176.80 191.63 207.55 219.25 227.13 237.73 248.68 256.38 264.35 271.06 276.50 284.95 289.23 289.23 287.75 281.98 276.35 270.83 265.40 258.78 251.00 243.48 6476.63  Ul  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.1 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  AvW .154 .390 .650 1.24 1.74 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  g  e s  (p+qi  Wt. Change Factor  Wt. of Av. Wt. Stock of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05  .04 .35 .04 .24 .04 .22 .04 .11 .04 .24 .04 .15 .04 .24 .04 .01 .04 .08 .04 .08 .04 .05 .04 .07 .04 .05 .04 .02 .04 .01 .04 .04 .04 .01 .04 .01 .04 .01 .04 0 .04 0 .04 .02 .04 -.02 .04 -.01 .04 -.03 .04 -.03 .04 -.03 .04 -.03 .04 -.03 .04 -.04 .04 -.04 .04 -.04  1.419 1.271 1.246 1.116 1.271 1.162 1.271 1.010 1.083 1.083 1.051 1.073 1.051 1.020 1.010 1.041 1.010 1.010 1.010 1.000 1.000 1.020 0.980 0.990 0.970 0.970 0.970 0.970 0.970 0.961 0.961 0.961  1419 1804 2248 2509 3189 3706 4710 4757 5152 5580 5865 6293 6614 6746 6813 7092 7163 7235 7307 7307 7307 7453 7304 7230 7013 6803 6599 6401 6209 5967 5734 5510  1612 2026 2379 2940 3448 4208 4834 4955 5366 5723 6079 6454 6680 6780 6953 7128 7199 7271 7307 7307 7390 7379 7267 7122 6908 6761 6500 6305 6088 5851 5622  64.48 81.04 95.16 113.96 137.92 168.32 189.36 198.20 214.64 228.92 243.16 258.16 267.20 271.20 278.12 285.12 287.96 290.84 292.28 292.28 295.60 295.16 290.68 284.88 276.32 268.04 260.00 252.20 243.52 234.04 224.88 7183.64  VD  97  inoomioooioiooo"NOinoinmiouNOinooioouNOinoou roooo\c\iCNini^ooNCftr^oo O s t O u ^ i n i n o o M N f o o o o ^ i n o o s t - noNb n ovoo <r voro r>- ONrv<f rv r-l <f CM ro HCMsf m rv co ON ON rv ON r-i ro vo ON C r-l r-l r-4 r-l M <M CM CM CM CM CM CM  • r4 >*  • CJ id ° w  O n  V.  CM rv o ON o CM ON < TVO vO <f VO 00 oo ON m m m m m  •'  > 4-1  r—l — i I CM CM CO CO <j"  < o  vf  r-l r-l r-l r-l O r w t vo rv m m m CM VD m ON <r rv o o o O ON ON 00 rv m vO VD vO vo m m m m m  M-l  Or* o •o 4-1 -U 13 CO  o o O  r-l CM r-l ON ON r-l vO 00 r-l vO vO m m b o00 o oo o C Mm m m m m m VO vO  r-i r-l o o m m ON CO o o ON ON vO vO mm  CJ p  u uo  r C  r-l O o o o o O C O ON ON OO o o o O ON ON r l r l r l H r l H H r l H r l r l r l r l r l r l r l r l r l r l O O r l O  • w •o  4 J i CD  +  a  CO CM CM — i I CM i—l CM  v> I 60  O O O O O O  O  O O O O O O O O O O v O O O I  I + I I t I I I I I I I  m m m m m m m mm m m m m m m m m m m m m m m m m m m m m i n m i n o o o o o o o o o o o o o o o o o o o o o o o o o o o o o oo o  i m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o  cr  <f ro i—t o ro <t ro o r v r v v t v O v t r - ^ o c o o o o o N O N r - i r v o o v o v o v o v o v o m m m s t O O n M f O O J n Hr-I r-lr-lf-li-lr-l r-l i-l i-l i-l rl O O r-l O O O O O O O O O O  00 <r o o  m ON m vj-r» vo vo o o m l-^fOvoN^^d'nr^^^^^^r^NvooNNl-lOr-loo^^^«J'c^lo^t»No^cOr^^ooo r ^ ^ 4 c > J ( n s J l ^ l ^ o ^ ^ c ^ l n o O l - ^ < f ^ O ' * ^ r ^ ^ o o l n r ^ l o O l O C ^ 4 0'n'-^^o r^r-IHHr-INNNncOfO^^i/iinvDvONNrvCOONONOO r-l r-l r-J  o o OHNQinNHOOVDCftOOO00  0\00inOO^NChvONO<OONinNON^N  ON CM vtKoNr^vtvoooocomr^ONOcMv^voooOr-icn^voooor-icnvjm oo  Or-tcMcov^mvorv.oooNO^cMcnv^mvoiv*cooNOi-tcMcovjm i-ICM<nvjmvOrvOOCT»r-4r-lr-<i-lr-4r-lr-lr-lr-lr-ICMCMCMCMC^  98  csovooo>tfoococNi\oc\i<rvovo^o«cro^ vO i-N. m c r » O r - * c o c ^ v o c M < f c ^ r ^ c o o o c o c » r > . v D r - i r H c M v o c « CM .—i n i O N v O t O r - I ^ O ^ O C O O V r ^ v C v J VO f r-l f>.V-l CO CM CM CM ON r - l A v f CM H O C M O N r ^ r n i n c o c M ^ i n v o r ^ c o o o o o o o o o N O x c o o o r " . vo <r ro oi*<-< o ovco:vO .-IHIHT-4CMCN«CMCMCMCMC^COCOCOCOCOCOCMCMC^ m  CM  r-icMawoH vooo\oocNjco<fr-(coo\in^-ico<roorvco <t ro CM o co o c o r ^ c M i n i n O r - K t v o m i n i n r v c o c o o vOCOOHOrJr^OOONOOOOMDOO'-IOMOfOHO'  VO m T-l o m o> O CO CO CM VO o VO CM CM CO CO  vDCM  t—11—t  o o o  Hcovoin>cfincocNicnoc\icvjvovoinvD>*cocMcM<fsfr^ cr\onrJHoooo(>ino^rHioooiniooiooooO'-ir >inininkDooo3o\i-i ( r ) ^ ^ ^ o ^ o o N o o c ^ l n ^ ( ^ ^ ^ r ^ o ^ ^ ^ ^ o o c ^ o o o o v o < f CVIOMVD^NOON r^HcMCMcMco<t<r<t<f^<fininininininin^.<r<t^ s  HvOr-lsfy30NVOOCN|Nr-lr-(i-(  O O O O O O O O O r - l  O ' - f r - H r - l r - l r - I C M C M CM  Ov<tCMCT><rrOsf^vOvOcOincnOCTkCMONO>C^ nNNoiN^N^ooooooo^o^oi^ONONO^c^ONac^^ONO^c^o* Hf-l^-l^-lr-l^-(>—IO'-i<-H>—iT-tHr-lO'—(OOOOOr-IOOOOOOO  o o o  nNO^N(nNr^vOvOnu^nO^Nr^r^r4'NNO^niAiniTilOinvO»OvO CO CMCM O CM r-t CM O O O O O O  O O O O O O O  I  I  I  I  I  I  I  1  O  O  O  O  O  Q  O  I  I  I  I I  I  I  O  O  I  O  I I  vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO vO in vO vO  oooooooooooooooooooooooooooooooo inininininininininin>ninininininininininininininuoinininin^ O  O O O O O O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O  O O O O O O O  o o o  ^fO»-IO(*)<f rnONOi^^O^i-IOPlOOOffi^i-lNOOvOvO^OvOvOiA <3" COCO CM t O N n r l H H H r l H H H H r l r l H O O H O O O O O O O O  iniO  oo  <f o o  m cy>in <r <i- vo vo o o m  r^co^oc^l^^J^H^c^^l^HN^oNNHOr^co^^sf^^o^too(^lo^cO'-^^-lOo r - i > - 4 c M c o < j " i n r ^ O t - i f O i n o o I-H <ji—11—11—11—11—< CMCM  r^o<fr-.r-(voom«-iinomON<i-oiOT-i\o CNicococo<t<l"ininvovor>>.f^r^coo\ONOO  Ol^NOln^r^^^fn^oc^oooMC^oolAOOvpcJC^vD^lOlnoNl^l^oN^o^. ONcM^r ON«-< <r voco o c o i n N c ^ o N ' < t v o c ) O O r - i p N < f \ o o o O ' - ( c n v d - i n v o o o o \ o ^ r-4r^i-^r^cMcMcMcMcococococo<f<r<fr>tf<frinin  <-l CM CO <f in vO r-- OO.OVr-l i-IHHr^r-lr^T-lr-tt-ICMCMCMcMCMCMCMCMCMCM CO CO CO CO CO CO  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.6 101.0 106.0 -• - •••  g  q  P  Change g-(p+q) Wt. Factor  Wt. of Stock  Av. Wt. of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 . 10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05  .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075  .315 .205 .185 .075 .205 .115 .205 -.025 + .045 + .045 + .015 + .035 + .015 -.015 -.025 + .005 -.025 -.025 -.025 -.035 -.035 -.015 -.055 -.045 -.065 -.065 -.065 -.065 -.065 -.075 -.075 -.075  1.377 1.234 1.209 1.083 1.234 1.128 1.234 .970 1.051 1.051 1.020 1.041 1.020 .980 .970 1.010 .970 .970 .970 .961 .961 .980 .942 .951 .932 .932 .932 .932 .932 .923 .923 .923  1377 1699 2054 2224 2744 3095 3819 3704 3893 4092 4174 4345 4432 4343 4213 4255 4127 4003 3883 3732 3586 3514 3310 3148 2934 2734 2548 2375 2214 2044 1887 1742  1538 1877 2139 2484 2920 3457 3762 3799 3993 4133 4260 4389 4388 4278 4234 4192 4065 3943 3808 3659 3550 3412 3229 3041 2834 2641 2462 2295 2129 1966 1814  115.350 140.775 160.425 186.300 219.000 259.275 282.150 284.925 299.475 309.975 319.500 329.175 329:100 320.850 317.550 314.400 304.875 295.725 285.600 274.425 266.250 255.900 242.175 228.075 212.550 198.075 184.650 172.125 159.675 147.450 136.050 7551.825  LOO  vovot7\vOHmnooor-iOr-iin^inH vo r-i i n i n i n c M r - i o o , - i < t - < f c o r v . r - i c o ro vt cNincNi^voirjoor^r^incovoo<rcNc>.^o<r o CM ON m m CM CO CO o\ vO ON O CM CO ON <r O C O ON <t ooo rv. v t CM <t CO NO ro m co r-l r-l O oo O C M <r i-v o r-l ON ON oo r v in CO CM r-< ONf-CO CO CM CM CM CM CM CM CM CM CM i—I i—1 r-l r-l r - l r-l r-l r-l rv r-i CM CM CM CM m  r-i •rl  • o 4J O is 4 J  CM CM CO CM rv. mv t NO CO rv. O r l CO ON ON CO r-l o 00 CM <frvo rv. oo oCO <t CO CM CM r-l CM CM CM CM CM CM r-l r-l  to  > IW  r-t  X  0  » CM rv. mmm<r NO r v oo CO NO ON r v r-l Orv. mCM in r NO ON 00 <r CM r-l ON r v NO mNO rv. CO ON r-l <t CO CM rv. CO r-l OON 00 r v NO v t co CM r-i o ON CO rv. NO NO mvT v t CO CO CM CM r-l r-l r-l r-l r-l r-l r-l r-l r-l  v t r-l CM 00 mmCO r-l CM CM ON r v co CO m i—i NO 00 m co CM CM r-l r-l o ON rv. NO CM CM CO CM CM r-l r-l r-l r-l r-l  :0 O  ;o  CM rv. CM o r o CM r-l r-l  CM r v o CO ON m r-l OCM CM CO r o m oo r-l OON co rv. NO m r-l r-l  00 C  o o r-l Or-l CM ON ON NO oo NO r o ON ON ON ON ON ON  o •U: CO  + P. v>  NOincocsimNomcOr-i r-ist<Msfivooinooooooo\ONrsH OCMCMCMCMCMCOCOCO CMr-lr-IQr-IOr-IOOOOOOOOOOOOOOOr-lr-lr-lr-lr-lr^rHlT-lr-lr-l  I  60  I  I  I I  I  I I  I  I  I I  rororococMrorococoiv»c^cococococococococococ^  • inin^ininininininininininininininininininininininininini^ OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO  a*  '.fs.vt ro r—i o co v t co orv r v . <r NO <}• r - i oco oooo"NONr-irv.covovovovo NO m m m ;<fOCONCOCN!OOHr^ r ^ H H r H r l r - I H i - l r - l r H O O ' - l O O O O O O O O O O  60  oo m ON m <f r v NO vo o o m  vt  r-IC^^CMrv.vtCOr-lrv.CMr-lr-tCMvOOCMCMr-1  O i-< CO | v . r - l <f CM O v t C O C M O N O O r - l v O O O  r - l r - I N r O s t ^ r s O H t ^ i n O O r ^ < f N O < f l ^ ^ ^ O ^ H i n O ^ ^ < f O l O r - l \ 0 r^r^^r-i.HCNicNicNinntn^^tninvovoivNNOooNONOO o o om  i < 0) 60  <  oo  OHNO<fN^O^^O\OOOWONOOlOOOvONffi«3NOiriONiriNONvON O N N > J N C ^ r ^ s J v o o O O n I O N ^ON>d"vflOOO>Hro<f vOOO O'-'fOKf mvOoOONOr-l r-ir-ir^r-icMcMcMcMcococococo^rvtvtvtvtinuoininininNOv^ , o r-i CM co v t m NO r v . co ON o I-I CM CO <r m vo r v oo ON O .-icMco^rin i—i CM ro v t m vo r v co ON r-i H ^ r ^ H H r ^ r - i H r ^ c s i N o J N N C N l c M N C N i N r o r o n n n f O  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 32.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  AvW .156 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34,1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.6 101.0 106.0  g  q  P  g-(p+q)  Wt. Change Factor  Wt. of Stock  Av. Wt. of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05  .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25  -.14 + .03 + .01 + .10 + .03 -.06 + .03 -.20 -.13 -.13 -.16 -.14 -.16 -.19 -.20 -.17 -.20 -.20 -.20 -.21 -.21 -.19 -.23 -.22 -.24 -.24 -.24 -.24 -.24 -.25 -.25 -.25  1.150 - 1.030 1.010 .905 .970 .942 .970 .819 .878 .878 .852 .869 .852 .827 .819 .844 .819 .819 .819 .810 .811 .827 .795 .803 .787 .787 .787 .787 .787 .779 .779 .779  1150 1185 1197 1083 1051 990 960 786 690 606 516 448 382 316 259 219 179 147 120 97 79 65 52 42 33 26 20 16 13 10 8 6  1168 1191 1140 1067 1021 975 873 738 648 561 482 415 349 288 239 199 163 134 109 88 72 59 * 47 38 30 23 18 15 12 9 7  292.00 297.75 285.00 266.75 255.25 243.75 218.25 184.50 162.00 140.25 120.50 103.75 87.25 72.00 59.75 49.75 40.75 33.50 27.25 22.00 18.00 14.75 11.75 9.50 7.50 5.75 4.50 3.75 3.00 2.25 1.75 3044.50  102  oiooomiriyiou-iirioinoioininoioin v t o m t o m i n m o i o i o mlm •ncMOOc^iNCNiocMcNiocMincMr^r'vinr^ OHvjOi-iNoo^^ooor^^Ln^^ONQOo^oorsCNicrvoooxcninvo o h »  O  «  *  *  .  *  «  e  0  O  «  O  O  O  O  O  O  O  O  6  0  0  9  0  6  0  0  0  0  0  O\00 ir> in CM r-ivf o v£> O m rv pv rv rvrvLoro • Ol^roc^c^oocnc^vtcyiin n<t mvorv oNOOr^r^NcsicsiNNCNiNNcxiNNHHoocyiCfiooflorviNin r^i^r(r(^r(r(rlr-lr<Hr)r(rHrlr(i-(r(r( JrO  CM lO VD O lO CTiCO v O I V i - I N C r > v O H N N N r - l i n v D N v r H H N c O C \ < f i r i O > ^ ^ 0  * O ^ ^ J *0«3 0 H O r - i r - * 0  rHrHCMCMrorOv^vJstvjv^ixiu^inmininm  O o r-l  CONtO  0 0 > C O O O N i f i r i r - i O \ N i n r H O  Cft^^r^oooOONiriONi-linOOiniriOinOOOONMvOiriiriyDOOOOlJir-l cnrvr-irooocMo oro i n N o v ^ H O H t - i o o ^ o o K n a s r N o a j ^ s r N o t T i r^i-lCMCMCMCOvtvtvTvt<rvJir)inLninin  rlvOrl4vO(J\«5 0 N N r - l r l f - I O O O O O O O O O r ) O H H r l r l r ( ( M M C M c\ -t CM ONvovoroLoroooNCMcyvaNcrvQOcx) o v D r v i n i n i n i r i i n s t < f < f o  o  o  o  «  «  O  9  e  o  o  »  o  o  c  >  o  o  o  0  O  o  o  «  «  e  o  o  Q  o  o  *  o  r-lrHr^r-lrHr-ll-^OrHr-4rHrHrHr-IOl-IOOOOOr-IOOOOOOOOCy>0  vDvOvDvDvDvDvOvtvOvDvOvDvOvtvtvOr-l vt <t v t v t v t v t v t < r v t v t v t < r v t v t v t N r - i o N c o ^ c s i N r ^ i n i n N v j N o^r^<tHr^NN o ^ n i O L o i n i n i n o v D * o rocMr-iOcMr-ir-ioOOOOOOOOOOOOOOOOOOOOOOOO o  e  o  «  0  0  0  0  0  *  0  o  i ++  o  o  o  o  o  o  o  o  o  o  o  o  o  e  o  o  o  o  o  o  i i + i i i t i i i i i gi i i gi i  CMCMCMCMCMCvJCMCv]CMCMCMCMCMCMCMCMCMcMCMCMCM<N O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 0  0  *  0  0  0  00  0  * 0  00 0  0  *  0 0  0  0  0  *  0 0  0  0  0  0  0  *  0  cnc^<^ONC^ONC3Nc>c>^aNavo\(^c^  0000«DOOCOOOOOOOCOCOCOOOCOCOCOCOCOOOOOCOCO(X)OOOOCOTO  oooooooooooooooooooooooooooooooo  <fr CO CO CM P") CM C r-lir-lt-»r-l r-l r-l r - l r - l r - l r - l r ^ r - I O O r - ^ O O C  O O O O O O O  <f o o  LO CJN iT> vt rv vD vO O O lO r^nvONrv^COr^NCNlr^HNvOONN^O^OONW^NOsf O  *  *  «  0  4  0  0  O  O  O  O  O  O  O  O  C  O  O  C  O  O  Q  O  O  O  C  O  WN^OOr^r-lOO *  *  O  O  O  O  *  r-iHr-ii-ir^rNiNNfoncn^<rininvO\ONrvNooc!\o\oo  O r - I C M O i n i S r - t O r 0 \ 0 0 \ O O O 0 0 0 N K l i n O O v O N 0 N v £ l N O i n O ( M i n N O N > I l | v 0  0  0  r-iri  «  *  0  0  0  0  «  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  «  0  0  *  0  0  »  0  0  0  r-ir-i(NCMcMCMrorororocnvtvtvtvt<rinmminin  r-icMrovtmvorvoocy»i-^r-ir-ir-4r-ir-irHr-ii—ir-icsl<NCMcMcMcMcMCMcMCMcococorococo  0  103  o oo  vocMocNj<fvocN4ovo<rCNi<r<t OHN«t ^ r v co  o  O O A O O v O Ot^vD^r^ON|vNCOCOOO>*ON01vOO iNvOO 4'CA(n r-i CM < t <r <f ^ ^ ^ ^ uo <t < t stf c o c ^ vO >  ,  ro  <tOOlOCnT-*<tCOO<fvOC^r-lr-IOOtf^ incoocorv.csiinuovorvoocrvcorv.rv.vouovtcocMr^ r-ir-icMcMcvrrococococococococococococococococ^  O O O r-l  CO<rCNl^O\CV.VOCNOrv.<t*-^Or^ \ov£>Q\coOr-iuovTCT>corv.c^cooocococMr^ covooNr-ivoc^uovfirtrv.rv.cocykinr^ r^r-lr-ICMCNCMCOCOCOCOCOCOCOCOCOCOCOOOCOCOCOO^  r - l .00 VO v f v t NO CO  !  CM CM CM r—I r—I r—I 1—I '  c^H^(nrHOrlOr^r-^Or-(ooooOOO'-^r-lONr^NNNNN( ^(n^ ,  1  N0CMCT>fv.cMr-ICMfv,>tf<fr-lfOi-IOOrvOi^l^rv.\OO r-l r-l r-l r-l r-l r-l r-l O r-l r-l r-l rH r-l O O r-l O O O O O O O O O O O O O O O O '  r—Ir—Ir—lr-lr-(r—lr-IC>r-lr—Ir-tr—lr-ICT»ONr-IO^ ^ o c o i s o H O N < t < f H(n^^HNONNNf^fOr-ll^^^j•vo^ovovDvo^^^ C O C M i — I O C M r - I C M O O O O O O O O O O O O O O O O O O O O O O O O O I ++ + ++  O O O O O O O O O  I+  I  I I I I II I1 I  t  I I I  O O O Q O O O O O O O O O O O O O O O O O O O :  O^CTvO>ONO>CTvCy»Cy»ONO>CT»C^ OOCOOOCOCOCOOOCOOOCOCOCOCOOOCOCOCOCOC^  oooooooooooooooooooooooooooooooo! 4fOt-i O r ^ < r ( ^ 0 ^ ^ < r * < ^ l - ^ 0 c ^ o o o o ^ t ^ r ^ ^ c o ^ o ^ o ^ o v o ^ 0 l 0 l n l n 4nnNMNCnr-<r-lr-lt-l^r-<r-lr-lr-lrHr-lr-IOO'-IOOOOOOOOOO vf O O moMO<trv.\o\oooio r-ICn\OCMrv.<trOr-irv.CMr-lr-l CM VO O CM CM r-l O-—ICO|V,r-l<tCM O vt CO CM ON CO r-l 1—1 O O r-l r-l CM CO >tf iO |v« O r-l CO iO 00 <-l <t r^. O <f vO O "O r-l O <0 ON >J.O IO H VO r - i r H r ^ H i - i c v i N N n n n » t < f inio\ovONrvr>ooa>o>oo r-4 r-l OHN o ^ ^ i - i O f o ^ O N O O O o o c ^ M i n o o ^ N o v v o o j otnocNiiorsONvoN CT>CMNtfrv,C^'-l<tvOCOOCOiOrv.C3NOcMvtvOOOOr^ ,-4r-lr-lr-ICMCMCMCMCOCOrOOOCOvtvtvtv+<fl^  OrHcMnst^vor^oooNO^Nnstinor^oocTiO'-icNirnsrio r-l CM CO <t m vO rv CO CT» r - l i—I r - l r ^ r - I H H i - l r - l r ^ N N N N N N O j N N N n n n n n ( l r  i  104  •H  ininoioomiflOOininininooooifioooinino^ooi'i^'Oio u^r-(rv<frv.ir^vOCT\CTv<*r-4cac\l^  CM  v^(^^COOrHCMi-(sO<J>r-(C^O<fOvOO<fOOrH rv,oooNr-ico«AvovDvovorvrvrvvovDmmvtcocoCMi-ir-i  OA  o o N O O o o r w o v o i n rv  oo ro  r*  CJ O  4J  vt ON vt r-l CO 00 00 ON r o rv m o o vo CO 00 ONVO r-l r o m r o r o 00 C M m o o o o C M rv ON C M vO O C M C M COCO vt vt vt C M C M I-l r-l r-l r-l C M C M C O r o CO c o c o c o CO r o COCO CO  r-l  CO  CO  OA  <o 4-1  OX  : CJ O 4J £ CO  vt vt r o vt rv 00 rv ON ON rv.rv r o C M O VO CO moo vt r-l 00 co 00 00 in m m C M ON VO r o vo ON O v t rv C O r-l C M c o c o vt vt CO C M r-l O r-l r - l r-4 C M C M C M r o CO CO r o r o r o r o C O CO CO CO O •n  O O O r-l  CM r o  r-l r-l r-l  OO  e  CO  6  m o o O v o o o o v o r o r o o c M o r v v o o N v o v o v o m m r v c o v t c M c M CM CM CM I-I I-I I-I cocMr-locMr-^cMONoooooaNo^aNONO^c^aNONaNONONONONONONONONONON  4J  r-lr-lr-lr-lr-<r-lr-IOr-<rHr-lr-lr-IOOOOOOOOO OO  cr + a  O O O O O O O O  I—I r - l i-< r - l I—Ii—II—I ON I-I I—It-Ir-lr-IONONONONONONONONONONONONONONCJNONONONON  o c ^ ^ ^ o c ^ o a ^ f ^ n r o o c N O N o o o n n n ^ s r c N i v o i o N r ^ r v r v i v cooooo r O r - « i - l O r - l r - l r - I O O O O O O O O O O O O O O O O O O O O O O O O O I I I I I f i l l +++++++ +++ + I I I I I  I  60  mmmmminmmmmmminmmmmmmmmmmmmmmmmmmin o o o o o o o o o o o o o o o o o o o o o o o o O O O O O O O O  1  ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON  X) CO C O 0 0 C O C O 0 0 0 0 0 0 C O 0 0 0 0 0 0 0 0 0 0 C O 0 0 0 0 C O 0 0 C 0 0 0 0 0 C O O T 00 00 00 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O C O vtro r - i o c o v t c o o r v r v v t v O v t r - i o r o o o o o N O N r - i r v c o vovovovovo in m m vtrOrOCMCOCSlrOi-lr-lrHr-lr-lr-lr-lr-lr-lr-lr-lr-IOOr-IOOOOOOOOOO 60 vt o o moNrnvtrvvovoooin r-l c o vo CM rv vti r o r-l rv CM r—tr - < C M v 0 O C N l C M r v O r - I C 0 r v r - l v t C M O v t 0 0 C M 0 N 0 0 r - l r - I O O r-i•—i c N c o v t m r v . o ^ o i n c O r - i ^ t r v O v t r v r - i v o o i n r - i m o m o N v t ou"> r-i vo r-i I-I r-< I-I I-I CM CM CM c o c o c o vt vt m m vo vo rv rv rv oo ON ON o o  Oi-icMOmt^rHocovoaNOOOcocjNoomoovocMONvocNioinocMmrvocMvorv  > < 0) 60  <c  oiN^rsoNr-i - ^ v o o o o r o i o f v o N O N ^ ^ c o o r - i n N j v f l ^ O r - i r o ^ i n v o c o o N O r - i _ i r-i r-i r-i <M CM CM CM r o c o r o r o c o v t v t v t v t v t i n m m m m i n v D v o v o v o v o v o v o v o r v r v  I-I CM  c o  Or-icMrovtmvorvooc^Or-icMOvtmvot^ooo^Or-icMrovtm vt jn 'O rv oo ONr-|r-lr-4r-<r-4i-li-lr^i-lr-ICMCMCMCMCMCMCMCMCMCMCOrOr^ I-I  Age  AvL - - AvW  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.1 28.3 30.6 33.9 35.0  37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  g s  ,q M  p I  6  g-(P+q)  ' Factor W t  C t i a t l  g  e  - f Stock  W t  AY. Wt. Yield of Stock  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089  .06 .291 .06 .181 .06 .161 .06 .051 .06 .181 .06 .091 .06 .181 .06 .049 .06 .021 .06 .021 — .009 .06 .06 - +.011 .06 .009 _ .039 .06 .06 .049 .06 .019 .06 .049 _ .049 .06 — .049 .06 _ .059 .06 — .059 .06 _ .039 .06 — .079 .06 _ .069 .06 — .089 .06 .06 .089 _ .089 .06 _ .089 .06 — .089 .06 _ .099 .06 .06 .099 — .099 .06  1.336 1.197 1.174 1.051 1.197 1.094 1.197 0.951 1.020 1.020 0.990 1.010 0.990 0.961 0.951 0.980 0.951 0.951 0.951 0.942 0.942 0.961 0.923 0.932 0.914 0.914 0.914 0.914 0.914 0.905 0.905 0.905  1336 1599 1877 1973 2362 2584 3093 2941 3000 3060 3029 3059 3028 2910 2767 2712 2579 2453 2333 2198 2071 1990 1836 1711 1564 1429 1306 1194 1091 987 893 808  1468 1738 1925 2168 2473 2839 3017 2971 3030 3045 3044 3044 2969 2838 2740 2646 2516 2393 2266 2135 2031 1913 1774 1638 1497 1368 1250 1143 1039 940 851  88.08 104.28 115.50 130.08 148.38 170.34 181.02 178.26 181.80 182.70 182.64 182.64 178.14 170.28 164.40 158.76 150.96 143.58 135.96 128.10 121.86 114.78 106.44 98.28 89.82 82.08 75.00 68.58 62.34 56.40 51.06  4002.54  b U l  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  .154 .390 .656 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  Factor  Stock  of Stock  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 ,16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089  .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075 .075  .276 .166 .146 .036 .166 .076 .166 .064 + .006 + .006 _ .024 _ .004 _ .024 .054 _ .064 _ .034 .064 _ .064 _ .064 _ .074 _ .074 _ .054 _ .094 _ .084 _ .104 _ .104 _ .104 _ .104 .104 _ .114 .114 .114  1.323 1.185 1.162 1.041 1.185 1.083 1.183 0.932 1.010 1.010 0.980 1.000 0.980 0.591 0.942 0.970 0.942 0.942 0.942 0.932 0.932 0.951 0.914 0.923 0.905 0.905 0.904 0.905 0.905 0.896 0.896 0.896  1323 1568 1822 1897 2248 2435 2881 2685 2712 2739 2684 2684 2630 2501 2356 2885 2152 2027 1909 1779 1658 1577 1441 1330 1204 1090 986 892 807 723 648 581  1446 1695 1860 2073 2342 2658 2783 2699 2726 2712 2684 2657 2566 2429 2320 2219 2090 1968 1844 1719 1618 1509 1386 1267 1147: 1038 939 850 765 686 615  108.450 127.125 139.500 155.475  175.650 199.350 208.725 202.425  204.450 203.400  201.300  199.275 192.450 182.175 174.000  166.425 156.750 147.600 138.300 128.925 121.350  113.175 103.950 95.025  86.025  77.850  70.425 63.750 57.375  51.450 46.125  4212.75  Age  A L  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  V  Wt. Change g-(p+q) Factor  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 56.9 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  Wt. of Av. Wt, Stock Stock  Yield  1000 .44 .33 .31 .20 .13 .26 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089 .089  .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13  + .221 .111 .091 -.019 .111 .021 .111 -.119 -.049 -.049 -.079 -.059 -.079 -.109 -.119 -.089 -.119 -.119 -.119 -.129 -.129 -.109 -.149 -.139 -.159 -.159 -.159 -.159 -.159 -.169 -.169 -.169  1.246 1.116 1.094 0.980 1.116 1.020 1.116 0.887 0.951 0.951 0.923 0.942 0.923 0.896 0.887 0.914 0.887 0.887 0.887 0.878 0.878 0.896 0.861 0.869 0.852 0.852 0.852 0.852 0.852 0.844 0.844 0.844  1246 1391 1522 1492 1665 1698 1895 1681 1599 1520 1403 1322 1220 1093 969 886 786 697 618 543 477 427 368 320 273 233 199 170 149 126 106 89  1319 1457 1507 1579 1682 1797 1788 1640 1560 1462 1363 1271 1157 1028 928 836 742 658 581 510 452 398 344 197 253 216 185 160 138 116 98  171.47 189.41 195.91 250.27 218.66 233.61 232.44 213.20 202.80 190.06 177.19 165.23 150.41 133.64 120.64 108.68 96.46 85.54 75.53 66.30 58.76 51.74 44.72 38.61 32.89 28.08 24.05 20.80 17.94 15.08 12.74 3577.86  o  vj  108  o o o o oom o oom o ihommiooooCiininoinoiooinoino omommmrv. iriininoJinNinNiNrNOOO^NcsioNinNinNOrv o m ON o o ON rv t o CM coiovtvornrv.invoc^cMcx)vtrHcovoiOvtoocMr-irH  < u  rv VO v t CM r - ( O O O v t < N O O O r v . i n v t f O C M C M r - ( r - l r - ( CM CM CM CM CM CM — •< r-lrHi-l  > • " O 4J O 5: 4J  OOO CM 00 O CM rH vtCMCO lO vO r-i CM iO IV. rH CM O vt vt Pv rH vo co O rv. vo io <r co o r v ON rH [v. CM co CN Or-1 vt CO ro co vt rHONCvirivtrocMcM rH rH rH o ON ON 00 CC rv lOlO<t ro CM CM rHrH rH rr-l HrH  w > UH  <. o o o o rH  CJ  o U co  vt rv vt O rH m o vO CO CM CM r H  lOvt rH CM CO vO CO O ON VO CM rH CM r-t rH O OONON CO CO rH r-i rH  0) 60 C CO U0 ON lO rv. rH ON CO C O0rH rH 00 0 rv. r v 00  • O V CO  rHONCT>ONO\o>ONcr»cj»ONONCTvcjNONaNONONo^ o o N r n o ONOcn ffvNro o n n n - J ^ N v o ^ r v r v i v i v r N o o o o c o HOOHOOONHHr^HHNNNNNNNNNNNNNNCSNNNN  +  V  I 60  t i l l  I  O  V  O  O  N  N  I  I  t  I  I  I  I  I I I I  uoioioioioiouoinioiouoioiouotninioiotnioinu^ CMCMCMCMCMCMCMcMCMCMCMCMCMCMcMCMCMcMCMCMCMCMCMCMC^  QAONC>ONCT»C^ONO\ON^O\C*E^  CXJOOCOOOCOCOCOOOCOCOOOCOCOCOCOCOCOOOOOCOCOOOCOCO  o o o o o o o o o o o o  vt vt  o o oo o o o o o o o o o o o o o o o o  CO rH OOO vt 00 O (V. Pv Vt VO <t rH O CO OOOONONrHrvCOvOvOVOVOVDlOlOlO dCONCl N f l H H H H H H H H H r l H r l O O r l O O O O O O O O O O  60 vt O O  lO ON iO v t t v  vo  vO O O"0  rHCnvOOJh.sl-COr-l  Hr-I O J O O ^ N N OHCOrVrH^N 0 < f C O N C ^ C O r H r - l O O  rH rH CM CO v t i n r v OrH OO'OCOrH^trv.Ovtrv.rHvDO'OrHlOOlOONvtfOtOrHVO rHH rHrHrHNNNcnnrOsf^iniovDvorvrvrvoooNCjNOO O O C M O m r v r H O O O v O ONO  5 0>  60 <  OOCO^COuoOOvOCMONvOCMOiOOCMiOr-vOCMvOrv  ON CM <t (v. ON rH VT vO C O Q n i O N C > O N > t v O C O O - H f O « C f vOCOOr^rOvjvOvOCOCNOrl rH r H rH rH CM CM CM CMCOCOOOCOOOvtvtvtvtvtlOlOiOlO'OLOvOvOvOvOiOvDO  Or^NCOsJ L^vON WCTtOrWNr0^i^vOrvCOO\0'HNCO<f in rH CM CO vt.lOVD rv CO ON rH rHrH rHr-lrHrHrHrHrHcMCMCMCMCMCNCMCMCMCMCOCOCn0OC0CO  LO r> vt C M  Age  AyL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 56.5 66.7 68.0 69.2 70.6 71.7  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  „ ./, .\ ^....Change _ ^ l Factor  g  0+a  8  P  q ;  Wt. of Ay. , W . . Y i e l d Stock of Stock t  Y i e i q  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025 .025  .315 .205 .185 .075 .205 .115 .205 .025 .045 .045 .015 .035 .015 _ .015 .025 .005 _ .025 _ .025 _ .025 _ .035 _ .035 .015 _ .055 .045 .065 .065 .065 _ .065 .065 .075 .075 — .075 mm  -  1.377 1.234 1.209 1.083 1.234 1.128 1.234 0.970 1.051 1.051 1.020 1.041 1.020 0.980 0.970 1.010 0.970 0.970 0.970 0.961 0.961 0.980 0.942 0.951 0.932 0.932 0.932 0.932 0.932 0.923 0.923 0.923  1377 1699 2054 2224 2744 3095 3189 3704 3893 4092 4174 4345 4432 4343 4213 4255 4727 4003 3883 3732 3586 3514 3310 3148 2934 2734 2548 2375 2214 2044 1887 1742  1538 1877 2139 2484 2920 3457 3762 3799 3993 4133 4260 4389 4388 4278 4234 4191 4065 3943 3808 3659 3550 3412 3229 3041 2834 2641 2462 2295 2129 I966  1815  38.450 46.925 53.475 62.100 73.000 86.425 94.090 94.975 99.825 103.325 106.500 109.725 109.700 106.950 105.860 104.775 101.625 98.575 95.200 91.475 88.750 85.300 80.725 76.025 70.850 66.025 61.550 57.375 53.225 49.150 45.375 2517.425  o vO  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.9 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  Change g-(p+q) Wt. Factor  g  Wt. of Stock  Av. Wt,. of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .04 .04 .04 .04 .04 .04 .09 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04 .04  .300 .190 .170 .060 .190 .100 .190 .040 .030 .030 0 .020 0 _ .030 _ .040 _ .010 .040 .040 _ .040 .050 .050 .030 .070 _ .060 .080 _ .080 .080 .080 .080 .090 .090 .090 mm  mm  mm mm  mm  mm  mm  mm  mm  mm  mm mm  1.350 1.209 1.185 1.062 1.209 1.105 1.209 0.961 1.031 1.031 1.000 1.020 1.000 .970 .961 .990 .961 .961 .961 .951 .951 .970 .932 .942 .923 .923 .923 .923 .923 .914 .914 .914  1350 1632 1934 2054 2483 2744 3317 3188 3287 3389 3389 3457 3457 3353 3222 3190 3065 2946 2831 2692 2560 2483 2314 2180 2012 1857 1714 1582 1460 1334 1219 1114  1491 1783 1994 2269 2614 3031 3253 3238 3334 3389 3423 3457 3405 3208 3206 3128 3006 2889 2762 2626 2522 2399 2247 2096 1935 1786 1648 1521 1397 1277 1167  59.64 71.32 79.76 90.76 104.56 121.24 130.12 129.52 133.36 135.56 136.92 138.28 136.20 131.52 128.24 125.12 120.24 115.56 110.48 105.04 100.88 95.96 89.88 83.84 77.40 71.44 65.92 60.84 55.88 51.08 46.68 3103.24  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  •9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69,2 70.6 71.7  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.6 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  g  q  p 1000  .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 . 10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05  .290 .180 .160 .050 .180 .090 .180 .050 .020 .020 - .050 .010 — .010 — .040 - .050 - .020 — .050 — - .050 .050 — .060 - .060 - .040 .080 — .070 — .090 - .090 — -090 - .090 -- .090 . 100 — .100 .100  1.336 1.199 1.174 1.051 1.197 1.094 1.197 0.951 1.020 1.020 0.990 1.010 0.990 0.961 0.951 0.980 0.951 0.951 0.951 0.942 0.942 0.961 0.923 0.932 0.914 0.914 0.914 0.914 0.914 0.905 0.905 0.905  1336 1599 1877 1973 2362 2584 3093 2941 3000 3060 3029 3059 3028 2910 2767 2712 2579 2453 2333 2198 2071 1990 1837 1712 1565 1430 1307 1195 1092 988 894 809  1468 1738 1925 2168 2473 2839 3017 2971 3030 3045 3044 3044 2969 2839 2740 2646 2516 2393 2266 2135 2031 1914 1775 1639 1498 1360 1251 1144 1040 941 852  73.40 86*90 96*25 108.40 123.65 141.95 150.85 148.55 15:1.5.0 152.25 152.20 152.20 148.45 141.95 137.00 132.30 125.80 119.65 113.30 196.75 101.55 95.70 88.75 81.95 74.90 68.45 62.55 57.20 52.00 47.05 42.60 3336.00  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 56.5 66.7 68.0 69.2 70.6 71.7  AvW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.0 90.1 95.1 101.0 106.0  g-(p+q)  g  Wt. Change Factor  Wt. of Stock  Av. Wt. of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .06 .06 .06 .06 .06 .06C .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06 .06  .280 .170 .150 .040 .170 .080 .170 -.060 .010 .010 -.020 0 -.020 -.050 -.060 -.030 -.060 -.060 -.060 -.070 -.070 -.050 -.090 -.080 -.100 -.100 -.100 -.100 -.100 -.100 -.110 -.110  1.323 1.185 1.162 1.041 1.185 1.083 1.185 .942 1.010 1.010 .980 1.000 .980 .951 .942 .970 .942 .942 .942 .932 .932 .951 .914 .923 .905 .905 .905 .905 .905 .896 .896 .896  1323 1568 1822 1897 2248 2435 2885 2718 2745 2772 2717 2717 2663 2533 2386 2314 2180 2054 1935 1803 1680 1598 1461 1349 1221 1105 1000 905 819 734 658 590  1446 1695 1860 2073 2342 2660 2802 2732 2759 2745 2717 2690 2598 2460 2350 2247 2117 1995 1860 1742 1639 1520 1405 1285 1163 1053 953 862 777 606 624  86.76 101.70 111.60 124.38 140.52 159.60 168.12 163.92 165.54 164.70 163.02 161.40 155.88 147.60 141.00 314.82 217.02 119.70 112.14 104.52 98.34 91.80 84.30 77.10 69.78 63.18 57.18 51.72 46.62 41. 76 37.44 3473.16  to  113  Ostmioirnriioioinooooininininoo^^^oiflinoinoMflio orv.iv»t^cNir^r^r^rvOinoOrvCNJCM  CN  OcMco<rvocooNcocorv.rvvDinvjcn<oc^  ro ro in ro  ON  i-4  •r-l  > CJ  > o to  CM  ON r ON  o vO  rv <r rH r-l r-l  ><4H  ro O N r - , ro r v v O CM CM CM CM oo r-l ON O N r v in ON CM mCO ON CM < r m<f CO ro CM rH I-I CM CM CM CM CM CM CM CM CM  < o  l-l mr-l CO 0 0 l-l i n r v CM m O N v t O N CM r-l in in in ro Or v mv t v t v t v t <r v t v D CO CM VO o m ON 0 0 fv V D < f CO CM rH O ON 0 0 r v v D min v T •cl-cn r-l r-i r-l r-l rH r-l r-l r-l l-l  rv rv  H-l  o o o  o  o  S cn  l-l  vO 00 vo  ON v t r H r v r v ON ON < r r vrv rv rv v t ON OO v t vt mON ON rH v t ro CM CM CO vt CM r H r H r H r H CM CM CM CM CM CM CM C M CM C M r H O 0 0  CM ro v 00 ro in rvD  ON vo  rH  o  o  vt O  inr v ON or H VDr vo inv t  rv  ONin v t v t oca  inv t  vt  CM ON 0 0 v t ON O CM r H r H ON 0 0 P v r v . VD CO r H r H rH rH rH rH rH  ro r H in ON in v t  r H 0 0 CM CO r v CO v t CO r o  cu 00  c  o o  u  vo  rv rv r H v t CO v t ro 00 o o O v t O -4 O r H CM CO r H CO C O C O v t v t CM in r v r v r v CO CO rCO v rv rv r H r v inCO r v r - r v CM ON ON V D CO VO CO CM in CM CM CM r H r H co O N O O O c o rH O H ON ON ON ON ON ON ON ON ON ON ON ON ON ON ON 0 0 ON CO CO CO 0 0 CO o CO r H r H o co co  CO JC U  5  oo  o  4J  O  4 J CO  5  rt.  cr + a  inininininininininintntnininininininini^ VOinnN^VDinNOOnr^(^VOrvvJNrvNOOMvOOCT\rH^r-tr-lr-INNN N r l r l O - I O r l O O O O O O O O O O O O O O O ' - I O ^ r f r l r l r l r J r l r l  v-» I 00  I I I I I  I  I  I I I I  |  I  I I  I  I  I  I  •mininininininininininininininininininin f v . f v . r v . r ^ r ^ r ^ f ^ r ^ r ^ r ^ r ^ r ^  o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o  o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o  H H H H H H H H H H H H i - I H H H H H i - I H H H H r - I H H H r - I H H HH  •d (OHOn4nONN<tvO<f ,  r-IO(nOOOCn0NHN00v0«\O\0v0ininiO  vf C O C O CM C O C M C O r H r H r H r H r H r H r — I r — I i — I r H r H l — l O O r H Q O O O O O O O O O  00 vt  oo  inoNinvtrvvDvooom  1-ltOvOCMr^vtCOrHrv.CMrHrHCMvOOCNCMr-IOi-IM i—irHcMcovt i n r v O r H c o i n o o r H v J - r v o v t r v r H v o o i n r H i n o m a N v t O i n r - i v D r_i ^ r H r H r H CM CM CM co co co vt vt in in VO VO rv rv 00 ON ON o o  OHNOiONHOnvOaiOOOOO^OOinOOvONONvONOiOONiONOCvlvOS  < CD 60  ON CM vtrv.a>f-Hvtvoc»ocoinfv.a>ocNvtvoc»OrHcovtv^ rHrHrHrHCMCMCMCMCOCOCOCOCOvtvtvtvtvtinininm  OHNrn<rinoNcoc^O'^NrnvtinorvcocJNOrHNrO'tiO  H N C O ^ l O v O N C O C T i H H r 4 r H r 4 H r - I ^ H r ^ N N C \ | C S N  CM CM C M C M C M C O C O C O C O C O C O  I  Age  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65,5 66.7 68.0 69.2 70.6 71.7  AvW .154 .290 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  8  q  p  Wt. Change g-(p+q) Factor  W . of Stock t  Av. Wt. of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .12 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13 .13  .210 .100 .080 -.030 +.100 + .010 + .100 -.130 -.06 -.06 -.09 -.07 -.09 -.12 -.13 -.10 -.13 -.13 -.13 -.14 -.14 -.12 -.16 -.15 -.17 -.17 -.17 -.17 -.17 -.18 -.18 -.18  1.234 1.105 1.083 0.970 1.105 1.010 1.1052 . .878 .942 .942 914 .932 .914 .887 .878 .905 .878 .878 .878 .869 .860 .887 .852 .861 .844 .844 .844 .844 .844 .835 .835 .835  1234 1365 1477 1433 1583 1599 1767 1551 1461 1376 1258 1172 1071 950 834 755 663 582 511 444 386 342 291 251 212 179 151 127 107 89 74 62  1299 1421 1455 1508 1591 1638 1659 1506 1419 ' 1317 1215 1122 1011 892 795 709 623 547 478 415 364 317 271 232 196 165 139 117 98 81 68  168.87 184.73 189.15 196.04 206.83 212.94 215.67 195.78 184.47 171.21 157.95 145.86 131.43 115.96 103.35 92.17 80.99 71.11 62.14 53.95 47.32 41.21 35.23 30.16 25.48 21.45 18.07 15.21 12.74 10.53 8.84 3206.84  Age'  AvL  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35  9.0 12.1 14.2 17.0 19.5 21.7 24.1 26.0 28.3 30.6 33.9 35.0 37.0 39.0 40.8 42.9 44.8 46.5 48.0 50.0 51.6 53.2 54.9 56.6 58.2 60.0 61.5 63.0 64.2 65.5 66.7 68.0 69.2 70.6 71.7  AyW .154 .390 .650 1.24 1.77 2.46 3.36 4.10 5.70 7.25 10.1 11.1 13.2 15.6 18.0 21.2 24.2 27.1 30.0 34.1 37.8 41.7 46.1 50.4 55.2 61.0 65.4 70.8 75.2 79.9 84.8 90.1 95.1 101.0 106.0  g-(p+q)  g  Wt. change Factor  Wt. of Stock  Ay.. Wt. . of Stock  Yield  1000 .44 .33 .31 .20 .33 .24 .33 .10 .17 .17 .14 .16 .14 .11 .10 .13 .10 .10 .10 .09 .09 .11 .07 .08 .06 .06 .06 .06 .06 .05 .05 .05  .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10  .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25 .25  .09 -.02 -.04 -.15 -.02 -.11 -.02 -.25 -.18 -.18 -.21 -.19 -.21 - .24 -.25 -.22 -.25 -.25 -.25 -.26 -.26 -.24 -.28 -.27 -.29 -.29 -.29 -.29 -.29 -.30 -.30 -.30  1.094 .980 .961 .861 .980 .896 .980 .779 ,835 .835 .811 .827 .811 .787 .779 .803 .779 .779 .779 .771 .771 .787 .756 .763 .748 .748 .748 .748 .748 .741 .741 .741  1094 1072 1030 887 869 779 763 594 496 414 336 278 225 177 138 111 as 67 52 40 31 . 24 18 14 10 7 5 A  3 2 1  1083 1051 959 878 824 771 679 595 455 375 307 252 201 158 125 99 77 69 46 36 28 21 16 12 9 6 5 4 3 2 1  270.75 262.75 239.75 219.50 206.00 192.75 169.75 148.75 113.75 93.75 76.75 63.00 50.25 39.50 31.25 24.75 19.25 15.00 11.50 9.00 7.00 5S25 4.00 3.00 2.25 1.50 1.25 1.00 .75 .50 .25 2284.50  Cn  

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