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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 . (London), 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 Master of Sc ience i n the Department of Zoology We accept t h i s t h e s i s as conforming t o the r e q u i r s tandard THE UNIVERSITY OF BRITISH COLUMBIA OCTOBER, 1963 In presenting t h i s thesis i n p a r t i a l fulf i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the Library s h a l l make i t f ree ly ava i lab le for reference and study. I further agree that permission for extensive copying of the thesis for schola r ly purposes may be granted by the Head of my Department or by h is representat ives. I t i s understood that copying or Publ ica t ion of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my wr i t t en permission. Department of Zoology The Unive r s i ty 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 ive 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 Miss ion C i t y , B r i t i s h Columbia. Age was determined for 230 specimens from sections of the f i r s t pec tora l f i n rays . Sections from the rest of the mater ials were unreadable. 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 lso by back-ca lcula t ing growth at the di f ferent 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 lso by c a l c u l a t i n g weights at d i f ferent lengths using the length-weight r e l a t i o n s h i p . 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 af ter that age the females grow faster than the males. I t was a lso revealed that nei ther of the sexes grows to a f ixed maximum length. Study of growth i n i i weight revealed a s i m i l a r pattern u n t i l the f i s h reached 30", but af ter that length the females had an advantage over the males. An attempt was made to 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 tar t spawning at age eleven, but females may not spawn u n t i l they reach age twenty-five to twenty-seven. Periods between spawnings are var iab le i n the di f ferent i n d i v i d u a l s , but may range from f ive to ten years. A study of the mor ta l i ty rates i n the Fraser River white sturgeon revealed that the present f i s h i n g mor ta l i ty rate i s excessive. As a resu l t the f i shery i s now u t i l i s i n g f i s h from the young age groups, which may lead to the deplet ion of s tocks. Due to the inc iden ta l nature of the f ishery i t i s not pr a c t i c a l l y possible to introduce measures which would effect a reduction i n the f i s h i n g mor t a l i t y . I t i s suggested there be introduced measures which would protect the spawning stocks. These include in t roduct ion 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 she ry , and p roh ib i t i on of sturgeon f i s h i n g on the Fraser i n the area between Langley and Yale , B r i t i s h Columbia. v i i i ACKNOWLEDGEMENT I wish t o express tny s i n c e r e thanks t o the Westminster Pakcers L t d . f o r a l l o w i n g me t o handle t h e i r f i s h d u r i n g the c o l l e c t i o n of m a t e r i a l s , and f o r the i n f o r m a t i o n obtained from them r e g a r d i n g the white sturgeon f i s h e r y on the F r a s e r R i v e r . My u n l i m i t e d thanks are due t o Dr. P. A. L a r k i n f o r h i s guidance i n the a n a l y s i s of the data, and p r e p a r a t i o n of the manuscript. I am v e r y g r a t e f u l t o the f o l l o w i n g people; Dr. W. A. Clemens f o r o f f e r i n g v a l u a b l e s t i m u l a t i o n throughout the study, and f o r c r i t i c a l l y r e a d i n g the manuscript; and Drs. N. J . Wilimovsky and T. G. Northcote f o r t h e i r c r i t i c i s m s on the manuscript. Dr. C. C. Lin d s e y s u p e r v i s e d the e a r l i e r stages of t h i s study and o f f e r e d v a l u a b l e a d v i c e on the f i e l d work. My thanks are a l s o due t o many f r i e n d s who have helped me i n f i e l d and i n many other ways. I would a l s o l i k e t o extend my thanks to the Canadian U n i v e r s i t i e s Foundation under whose auspices I was awarded a commonwealth s c h o l a r s h i p which enabled me t o undertake t h i s study. i i i TABLE OF CONTENTS ABSTRACT i INTRODUCTION.. 1 MATERIALS AND METHODS 6 1) Measurements 6 a) t o t a l length. 6 b) fork length .6 2) Weight 6 3) Sex 7 4) Stomach Contents 7 5) F in Rays 7 Age Determination of the Fraser River White Sturgeon 8 Sources of Error i n Age Determinations 11 Growth of the Fraser River White Sturgeon 13 1) Growth i n length. 13 Method I . . . . . . . . . 1 3 Method I I 13 2) Growth of the di f ferent year classes . . . 19 3) Relat ionship between s ize and growth of the di f ferent year classes 19 Growth i n Weight of the Fraser River White Sturgeon 20 Age at F i r s t Spawning and Intervals Between Spawnings. . . . 20 M o r t a l i t y Rates i n the Fraser River White Sturgeon 21 Theore t ica l Y i e l d at Different Rates of Natural and F i sh ing 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 24 1) Growth i n l e n g t h . . 2 4 Growth of the d i f f e r e n t year c l a s s e s 33 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 c l a s s e s . . . . . 4 0 2) Growth i n weight 45 Length/weight r e l a t i o n s h i p . . . . . .49 Age at F i r s t Spawning and I n t e r v a l s 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 the F ra se r R i v e r White Sturgeon . . . 6 4 DISCUSSION v .67 MANAGEMENT .74 SUGGESTIONS FOR FUTURE MANAGEMENT. 78 SUMMARY 81 LITERATURE CITED 85 APPENDIX I . A n a l y s i s of Stomach Contents 88 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 Length and age of the male and female s turgeon of the F r a s e r R i v e r , May 1 to 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 capture f o r the male and female whi te s turgeon of the Fraser 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 lengths f o r the female s turgeon of the Fra ser 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 . . . . . . . . 3 4 Table IV Back c a l c u l a t e d lengths f o r the male s turgeon of the Fra se 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 . . . 3 5 Table V Average e m p i r i c a l weight f o r the male and female s turgeon 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 weights and c a l c u l a t e d weights f o r the male and female whi te s turgeon on the Fraser R i v e r , May 1 t o October 28, 1962 . . . 5 0 Table V I I Age at f i r s t spawning and subsequent spawnings i n the Fra se r R i v e r male whi te s turgeon .55 Table V I I I Age at f i r s t spawning and subsequent spawnings i n the Fra ser R i v e r whi te s t u r g e o n . . 55 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 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) .63 v i ILLUSTRATIONS F i g . 1 The r e l a t ionsh ip between fork length and r a d i a l length of the f i n ray sect ion (along s t ra ight l i ne ) 15 F i g . 2 The r e l a t ionsh ip between fork length and r a d i a l length of the f i n ray sect ion (along curved F i g . 3 Age d i s t r i b u t i o n i n the Fraser River white sturgeon commercial catches 27 F i g . 4 Length frequency d i s t r i b u t i o n of the Fraser River white sturgeon 28 F i g . 5 Growth i n length of the Fraser River male white sturgeon (average empir ica l fork length by age groups F i g . 6 Growth i n length of the Fraser River female white sturgeon (average empir ica 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 F i g . 7 Growth i n length of the female Fraser River white sturgeon (average calculated fork lengths by age groups) . . . . 3 6 F i g . 8 Growth i n length of the male Fraser River white sturgeon (average calcula ted fork length by age groups) 37 F i g . 9 Walford transformation of ca lcula ted lengths of the Fraser River male white sturgeon . .38 F i g . 10 Walford transformation of ca lcula ted lengths of the Fraser River female white sturgeon .39 F i g . 11 Calculated 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 Calculated growth h i s t o r i e s of the year classes of the male Fraser River white s turgeon. . . .42 F i g . 13 Relat ionship between s i ze and growth of the di f ferent female year F i g . 14 Relat ionship between s ize and growth of d i f ferent male year c l a s s e s . . . . . . . . . . . . . . . . . . . . . . 4 4 v i i Fig. 15 Growth i n weight of the Fraser River male white sturgeon (average weight by age groups) ..... A » i v . . . » . , . . . . •. .47 F i g . 16 Growth i n weight of the Fraser River female white sturgeon (average weight by age groups) .... 48 F i g . 17 Length/weight re l a t i o n s h i p for the Fraser River white sturgeon. .. 51 Fig . 18 Growth i n weight of the Fraser River white sturgeon, calculated weights at d i f f e r e n t lengths..........*...«.............. 52 Fig . 19 Growth i n weight of the Fraser River white sturgeon, calculated Weights at d i f f e r e n t ages ...................... 53 Fig . 20 Catch curve for the Fraser River white sturgeon................................... 58 Fig. 21 Y i e l d i n weight at d i f f e r e n t rates of f i s h i n g and natural mortality,,,.... 61 Fig. 22 Yie l d at fixed f i s h i n g but varlab1 natural mortality...... x 62 PLATES Plate 1 Cross section of the f i r s t pectoral f i n ray of the Fraser River white sturgeon showing the consecutive zones used i n determining age..10 P U t e 2 A cross section of the f i r s t p e c t oral f i n ray of the Fraser River white sturgeon showing r a d i c a l axes along which measurements for 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 length of the Fraser River white sturgeon..18 INTRODUCTION In a l l areas where commerc ia l ly 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 , there has been great d e p l e t i o n of s tocks and i n some p laces 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 causes . In the f i r s t p lace the economic importance of the s turgeon 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 they d i d t o the f i shermen ' s nets and the s u p p o s i t i o n that they fed on the spawn of more e c o n o m i c a l l y important s p e c i e s , attempts were made t o e r a d i c a t e them. Secondly , when the economic p o t e n t i a l of the s turgeon 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 the b i o l o g y of the sturgeon r e s u l t e d i n an i r r a t i o n a l u t i l i z a t i o n of the s tocks 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 accounts of the sturgeon show that s turgeon were f o r m e r l y very abundant i n Nor th American w a t e r s . Goode et a l . (1886) s t a t e d tha t i n Green Bay, W i s c s o n i n , f i shermen of ten took a hundred or more sturgeon i n t h e i r pound n e t s , but s ince they were f i s h i n g f o r w h i t e f i s h they regarded the sturgeon a nuisance and an annoyance. A few f i shermen were c o n s i d e r a t e enough t o lower the corner of a net and a l l o w the s turgeon t o escape, but most drew them out w i t h a gaf f -hook and r e l e a s e d them wounded, . . 2 or took them ashore and threw them on a re fuse heap, a s s e r t i n g tha t there 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 spea r ing of the sturgeon i n M i s s i q u o i R i v e r , New Y o r k . The eggs from the speared sturgeons covered the br idge and spear ing had to be s topped, not t o p r o t e c t the s turgeon but t o avo id the s t e n c h . Phyca (1956) mentions tha t the sturgeon were once abundant enough i n C a l i f o r n i a waters t o have been cons idered a nu i sance . The great d i s r e g a r d f o r the s turgeon seems t o have, a r i s e n from the f a c t tha t people i n those days d i d not know how t o cook them, and cons idered s turgeon a food f o r " i n f e r i o r p e o p l e " . Lack of knowledge on the f e e d i n g behaviour of the sturgeon l e d t o statements such as that of P r i n c e (1899) where he r e f e r r e d t o i t as " t h e most vorac ious of a l l the f i s h - e a t i n g s p e c i e s " and sugges t ing that " i t scours the spawning grounds of the great l ake t r o u t , the w h i t e f i s h and every other k i n d of v a l u a b l e market f i s h , 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 scooping i n whole schools of de fense les s f r y " . These "rumours" encouraged the wanton d e s t r u c t i o n of sturgeon s tocks i n favour of the other s p e c i e s . W i t h the beg inn ing of smoke c u r i n g and the use of s turgeon roe f o r making c a v i a r , the commercial e x p l o i t a t i o n of the sturgeon began and by 1880 i t had become an important branch of the f i s h i n g i n d u s t r y (Harkness and Dymond, 1961). S ince the b e g i n n i n g of the commercial e x p l o i t a t i o n of the sturgeon there 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 tocks tha t a l l the important f i s h e r i e s have been c l o s e d down at one time or ano ther . 3 Smith (1914) hinted at the decl ine 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 stated that the s i t ua t ion demanded an absolute p roh ib i t i on of capture or sale of sturgeon for a long term of years not less than ten years. Carlander (1947) documented the decl ine of lake sturgeon i n the Lake of the Woods from 1888 to 1947, while Harkness and Dymond (1961) and Sunde (1961) have discussed various f i she r i e s i n eastern Canada and Manitoba. Bajkov (1949) presented several curves showing the sturgeon decl ine i n Chesapeake Bay, Lake of the Woods, Lake Michigan, and the Columbia R ive r . These p e c u l i a r i t i e s i n the sturgeon f i shery have prompted inves t iga t ions in to i t s biology to which several workers have made varying cont r ibut ions . Harkness (1923) studied the rate 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 region, 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 hab i t s , food and growth, as w e l l as suggest-ing some measures of conservation. Cuerr ier and Roussow (1951) studied age and growth of the lake sturgeon from Lake St . F ranc i s , and St . Lawrence River , Quebec, while Cuerr ier (1951) reviewed the l i t e r a t u r e on age determination i n the sturgeon and out l ined the pectoral f in - ray 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 Rivers . Roussow (1957) considered the spawning p e r i o d i c i t y i n the sturgeon of northern Quebec and re la ted his f indings to h i s previous studies i n Lakes St . Louis and St . F ranc i s , the S t . Lawrence Rive r , the Danube and Dneister of Romania, and the Ura l and Volga Rivers . Sunde (1961) studied growth and reproduction of the lake sturgeon (Acipenser fulvescens) i n NelsOn RiVer , Manitoba. He considered the effect of f i s h i n g on the sturgeon populations, 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 ( P a l l a s ) ) , and Holzmayer (1924) on the growth of Acipenseridae. Kuzmin (1954) studied the s t ruc tu ra l and developmental changes i n the testes and ovaries of juveni le sturgeon (Acipenser guldenstadti Brandt) , i n Russia , ChugnoV (1925) and Classen (1944) studied the age and growth of the sturgeon while several 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 ishery On the Fraser River 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 ng l a s s (a form Of ge la t in made from the l i n i n g of the a i r 5 bladder of the sturgeon) that exis ted between the Indians and the Hudson Bay Company, but th i s trade had ceased by 1866. On the Fraser , as i n many other sturgeon waters of North America, the white sturgeon was not economically important In those days. When markets for caviar and smoked sturgeon opened up i n the United States , 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 sh ing industry and offered winter 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 sh ing industry was so remunerative at i t s s tar t that a large body of fishermen engaged i n i t . Peak production on the Fraser seems to have occurred after 1897 but wi th in three years the catch had f a l l e n to 207o of the i n i t i a l catch and by 1905 i t had been reduced by 93.370. The decline i n the sturgeon stocks was so pronounced by 1911 that some protect ive measures were taken. Only g i l l - n e t s and d r i f t T n e t s of 12" mesh were allowed and a closed season was declared from November 15 to March 25. The s ize l i m i t , however, was only 8" or three pounds. Catches continued to decl ine and although the s ize l i m i t has been rev i sed , the f i shery has s t i l l not been rev ived . The present s ize regulat ions al low fishermen to r e t a in only those f i s h that have at ta ined 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 indings can be u t i l i s e d i n achieving a maximum sustained y i e l d . 6 MATERIALS AND METHODS Most of the materials for th i s study were co l l ec ted 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 br ing 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 ega 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 fo l lowing data taken: 1. Measurements a) Tota l length. Length from the t i p of the nose to the t i p of the t a i l , w i th the t a i l drawn to the tape. b) Fork length. Length from the t i p of the nose to the fork of the t a i l wi th the t a i l spread out. A l l measurements were taken with a s t ee l tape and the length was measured to nearest one-quarter inch . 2. Weight Most of the f i s h were weighed with a Cha t i l l on spring balance of thirty-pound capaci ty , ca l ib ra ted i n one quarter pounds. A Larger scale balance was used for bigger specimens and a d ie tary scale for very small specimens. The recorded weights were for undressed f i s h . 3. Sex The f i s h were opened and sex determined by v i s u a l examination of the gonads. in some small specimens i t was necessary to use a microscope to determine the sex. The state of maturity of the f i s h was also observed. F i sh showing undifferent ia ted gonads were recorded as "young" while those showing r ipe eggs were recorded as " r i p e " , and those with d i f fe ren t ia ted gonads, but no r ipe eggs were recorded as "mature". Specimens that looked to have spawned recent ly were recorded as "spawned". 4. Stomach contents Stomachs from n ine ty - s ix sturgeons were co l lec ted and preserved i n a d i l u t e so lu t ion of formal in . Each stomach was l abe l l ed wi th the s e r i a l number assigned to the f i s h , and la te r examined i n the laboratory. Specimens taken i n ear ly May were f u l l of pu t r i fy ing eulachons. 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 poss ib le , was made by eye. 5 i F in rays For each f i s h a f i r s t pectoral f i n ray, and i n some cases both f i r s t pectoral f i n rays , were co l l ec ted by cu t t ing them off the f i s h at the point of a r t i c u l a t i o n with the pectoral g i r d l e . These were l abe l l ed wi th a paper tag car ry ing the s e r i a l number of the f i s h , which was t i ed to the f i n ray by a brass wire passed through the blood vessel that runs through the centre 8 of the f i n r a y ' s base. The f i n rays were then d r i e d i n the 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 de te rmina t ion of the F r a s e r R i v e r whi te s turgeon S e v e r a l methods are a v a i l a b l e f o r de te rmin ing the age of f i s h . These i n c l u d e the 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 , l ength- f requency d i s t r i b u t i o n , e t c . Not a l l these methods, however,are s u i t a b l e f o r a l l s p e c i e s . In the s turgeon , s e v e r a l workers 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 succes s . The s c a l e t e c h n i q u e , which has been used s u c c e s s f u l l y i n many other f i s h e s , does not apply f o r the s turgeon because these f i s h do not possess 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 (1924) , have used the scutes found on the back and s ides of s turgeon fo 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 scutes degenerate as the f i s h grow o l d e r and i n very o l d f i s h they d i sappear almost c o m p l e t e l y . Harkness (1923) used the o t o l i t h s t o age the l ake sturgeon (Acipenser r u b i c u n d u s ) , but po in ted out tha t o t o l i t h s from l a r g e r f i s h were very t h i c k and the r i n g s were o f ten i n d i s t i n c t . S e v e r a l o ther workers i n North America (Ba jkov 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 ag ing s turgeon. However, C u e r r i e r (1951) r e p o r t s tha t he d i d not f i n d the method s a t i s f a c t o r y i n h i s study of the l ake sturgeon (Ac ipenser 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 determinat ions on the Suvr iuga (Ac ipenser s t e l l a t u s ) from 9 c l e i t h r a l bones. Cuerr ier (L95L) reports that the clei thrum 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. F in rays have been used extens ive ly . Apparently the f i r s t published work using f i n rays i n sturgeon was that of Kleer i n 1916 (Cuerr ier 1951). In North America t h i s method has been used Bajkov (1949), Cuerr ier (1951), Probost and Cooper (1954), Phyca (1956), Roussow (1957) and Sunde (1961). I f a transverse sect ion of the f i r s t f i n ray i s cu t , i t shows successive l i g h t and dark zones. These are interpreted as i nd i ca t i ng the pronounced difference i n rate of growth between winter and summer periods. The v a l i d i t y of these zones to ind ica te age i s s t i l l under observation. However, the work of Holzmayer c i t ed i n Curr ier (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 with the age of the f i s h , Probost and Cooper (1954) have provided further supporting evidence from the length-frequency 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 he 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 pectoral f i n ray. As most of the specimens were taken from commercial catches t h i s was the only part which could be co l lec ted from the f i s h without rendering i t less acceptable to market. Thoroughly dried f i n rays were sectioned using a two-bladed saw. A transverse sect ion was taken a short distance from the base of the f i n ray. 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 to 0.5 mm were obtained. The sections were mounted i n pure glycerine and the age determined, using a binocular microscope and transmitted l i g h t , by counting the number of consecutive zones on the section. In most cases i t was not necessary to polish the sections, but i n some, p a r t i c u l a r l y i n the older ones, polishing was necessary i n order to make the zones more v i s i b l e . This was done with a No. 0 grade sand paper. Plate 1 shows a cross-section of a f i r s t pectoral f i n ray. Plate 1 Cross section of the f i r s t pectoral f i n ray of the Fraser River white sturgeon showing consecutive zones used i n determining age 11 Sunde (1961) reported the loss of annul i when the sect ion i s taken at a distance from the base of the f i n ray. I t was thus necessary to select a region where a consistent number of r ings could be obtained. This was done by taking s e r i a l sections at in te rva l s from the base of the f i n ray and counting the zones i n each sec t ion . In b ig fishes the in te rva l s were at one quarter of an inch , but th i s was r e l a t i v e l y reduced i n fishes smaller than 20"-. It was observed that most of the sections taken from the f i n ray base were d i f f i c u l t to read. This area coincides wi th 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 annu 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 ray. Sources of error i n age determination The structure of the f i n ray i s great ly influenced by the pattern of growth of the f i s h . Environmental factors l i k e 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 ins during migrat ion, presumably a l l lea\emarks on f ins which tend to obscure the winter and summer zones. Therefore, one source of er ror i n age determination ar i ses from the structure of the f i n i t s e l f . Some sections may show great erosion, p a r t i c u l a r l y i n the centre of the sect ion tending to "push" the f i r s t readable r i n g a great distance from the centre. This leads to underestimation of age and erroneous estimate of growth rate i n the f i r s t year. In some sections scars evident ly due to in jury may upset the 12 arrangement of the zones and thereby introduce errors i n age determination. Quite often the second f i n ray grows in to the f i r s t and confuses the arrangement of zones. This may resu l t i n some fusion of r ings or other complications which make age determin-a t ion d i f f i c u l t . I t has a lso been observed that some r ings tend to s p l i t in to two on one side of the sec t ion , thus making i t d i f f i c u l t to decide whether to take them as two fused r ings or one r i n g . Another source of error i s the region from which the sect ion i s taken as explained e a r l i e r . If the sect ion i s taken too near the base of the f i n ray there i s a danger of under-estimating the age of the f i s h due to the tendency of the r ings to fuse. I f the sect ion i s taken too far from the base the age w i l l be underestimated due to loss of r ings . A l l of these errors can be minimised by being consistent i n the sect ioning procedure and r i n g reading. 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 ig 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 wi th eroded centres, where a loss of a r i n g was suspected, one r i n g was added to the count. A l l r ings which seemed to s p l i t were counted as a s ingle r i n g . 13 Growth of the Fraser River white sturgeon 1 . Growth i n length Growth i n length of the Fraser River white sturgeon was studied by two methods: 1 ) by r e l a t i n g the length at capture to age, and 2 ) by back c a l c u l a t i o n . Method 1. Mean fork length of each age group (separating sexes) was calculated and plotted against age (Figs. 5 , 6 ) . Method 2 . (Back c a l c u l a t i o n method) The study of growth in length of the Fraser River white sturgeon by method of back c a l c u l a t i o n was done from sections of the f i r s t pectoral f i n ray. Before this could be done, i t was necessary to study the r e l a t i o n s h i p between the growth i n length of the f i s h and the growth of the f i n ray. For t h i s study, c l e a r l y v i s i b l e sections of the f i r s t pectoral f i n ray of f i s h whose age had been determined with confidence, were selected. Sections that showed many scars, and sections that showed incursion of the second f i n ray into the f i r s t were avoided. Each of these sections was mounted in pure glycerene and i t s image projected on a white sheet of paper using a scale projector at medium power. An outline of the image was traced on the paper and each r i n g was marked off at i t s point of curvature. Two measurements of the images were taken. One was the length of a l i n e running from the centre of the f i n ray j o i n i n g the marked off rings to the periphery of the section. In most cases t h i s was a curved or sinuous l i n e . The second measurement was a straight l i n e from 14 the centre of the section to the same point on the periphery. A map measurer was used to find the length of these two l i n e s . These two lines are demonstrated i n Plate 2 and w i l l henceforth be referred to as r a d i a l measurements. Plate 2 A cross section of the f i r s t pectoral f i n ray of the Fraser River white sturgeon showing r a d i a l axes along which measurements for back c a l c u l a t i o n were taken To obtain the relationship between growth i n length of the f i s h and growth of the f i r s t pectoral f i n ray, the fork length of the f i s h was plotted against the straight and curved r a d i a l measurements of the f i n ray sections (Figs. 1, 2> Fig L The relationship between fork length and radial length of the f in ray section (along straight line ) 16 90 80 70 cn ui o 60 50 x i — o z UJ 401 on o u- J O 20 10 o o o o o e> o/6 o OOOyo o 0 0„ _ o / ooo 0 0 O BO O OO 0 o o o / o a oo o o Xoo8 o o / ° o I 2 3 4 5 6 7 8 RADIAL L E N G T H OF FIN RAY S E C T I O N Fig 2 The relat ionship between fnrk U r .g th and rad ia l length of f i n ray s e c t i o n (along c u r v e d line )• 17.. It w i l l be noticed that although there i s a certain amount of scatter of points, a l i n e a r r e l a tionship i s suggested i n both cases. Regression lin e s were f i t t e d on these using the method of least squares. The'equations obtained are:; . Y = 0.9 > 9.5x (along curve) ...1 Y =-3.1 .t 10.2x (along straight line) ...2. This, therefore, 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 pectoral f i n ray. These equations could be used for back c a l c u l a t i n g growth at d i f f e r e n t years, substituting a measured length between rings, for x. These two relationships had.the same co 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 l i n e showed a smaller standard deviation from the regression 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 ca 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 rings were measured. In many cases these were, so close together that i t was d i f f i c u l t to obtain > accurate measurements without further magnification. This d i f f i c u l t y was. overcome by projecting the image.on a white card-board using an epidiascope which magnified the image two to four times without d i s t o r t i o n . The distances between the rings were then measured with a map measurer-. A. nomograph was made to speed up the c a l c u l a t i o n . This consisted of a hard cardboard which had.a fixed scale representing the length of the f i s h , and a movable scale representing the r a d i a l measurements of the. f i n ray. A cotton thread used for i n t e r p o l a t i o n was fixed to one end of the base l i n e which cuts the f i s h length scale at the point of intercept of the regression l i n e (plate 3) . 18 Pla te 3 A nomograph used i n back ca l cu l a t i on of length of the Fraser River white sturgeon Thus the nomograph, by method of s im i l a r t r i a n g l e s , solves the r a t i o F i sh length at age x _ F in ray measurement at age x F i sh length at capture F in ray measurement at capture where the length at capture i s f i r s t corrected for the length at t heo re t i ca l zero f i n ray measurement. 19 Results of the back ca l cu l a t i on are given i n Tables 4 and 5. The ca lcula ted lengths at dif ferent 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 after t h i s age there were only a few specitnents. Calculated lengths were p lot ted using the Walford transformation by p l o t t i n g length at time t + 1 against length at time t (F igs . 9 and 10). 2. Growth of the di f ferent year classes To study growth of the di f ferent year c lasses , lengths at the di f ferent ages wi th in year classes were averaged, and p lo t ted against t he i r ages i n the di f ferent calendar years throughout t he i r l i v e s (F igs . 1.1, 12). 3. Rela t ionship between s ize and growth i n the di f ferent year classes To study the r e l a t i onsh ip between s i ze and growth i n the di f ferent year classes the method of L a r k i n , Terpenning and Parker (1956) was employed. The instantaneous growth rates for the di f ferent year classes were calcula ted and p lo t ted against fork lengths at the beginning of the year of growth (Figs . 13, 14). The instantaneous growth rates were obtained by taking 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 using the length/weight r e l a t ionsh ip ( F i g . 17). The length/weight r e l a t ionsh ip 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 ines on these plots by the method of least squares. The equations for these l ines were then used to ca lcu la te the weight of the f i s h at d i f ferent lengths. Age at f i r s t spawning and in t e rva l s between spawnings Age at f i r s t spawning and in t e rva 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 annuli and from the study of f luctuat ions i n growth curves. The method followed i s that of Roussow (1957). Roussow (o£ c i t ) indicated that the growth of gonads causes great re tardat ion i n the rate of growth of the f i s h , and that during spawning the males and females lose 1/10 and 1/5 r e spec t ive ly , of t he i r body weight through exudation of mi l t and eggs. These differences i n the growth rate of the f i s h and the f luctuat ions i n the body weight are re f l ec ted i n the curves of growth i n length and weight. The re tardat ion of growth during the bu i l d ing up of eggs and sperms i s marked i n the f i n ray sect ions . During t h i s per iod, annul i are l a i d down close to one another forming a narrow zone of concentrated annul i which Roussow c a l l s "be l t " . 21 Af te r spawning, normal growth i s resumed and annul 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 te r than the year immediately fo l lowing spawning. Thus by counting the annul i up to the end of the "bel t" the age at f i r s t spawning was determined. Intervals between spawnings were then determined by counting the number of annul i between successive "be 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 ipe eggs. In addi t ion 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 noticeable difference i n the arrangment of the annu l i . M o r t a l i t y rates i n the Fraser River white sturgeon In unexploited f i s h stocks i t i s possible to obtain d i r e c t l y an estimate of na tura l mor ta l i ty by studying the age frequencies i n a sample taken randomly. In exploi ted populations, however, mor ta l i ty rate thus obtained i s a component of both na tura l and f i s h i n g mor t a l i t y . If the magnitude of f i s h i n g i s known, the na tura l mor ta l i ty i s obtained by "subtract ing" f i s h i n g mor ta l i ty from the t o t a l mor t a l i t y . For the Fraser River sturgeon, i t i s d i f f i c u l t to estimate separately the magnitude of e i the r f i s h i n g or natura l mor ta l i ty for the f i shery i s only i n c i d e n t a l to the salmon f i she ry . These, therefore, can only be a r r ived at i n d i r e c t l y and wi th a ce r t a in amount of speculat ion. The t o t a l mor ta l i ty rate 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®, obtaining a catch curve the slope of which was used to estimate the t o t a l mor ta l i ty ra te . Ricker (1947) has shown that th i s method of estimating mor ta l i ty rate i s affected by three p r i n c i p a l sources of e r ro r , one of which i s systematic and the other two random. The systematic error ar ises 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 ferent ages to the f i sh ing gear. In the case of sturgeon,young f i s h wi th prominent scutes are more vulnerable to the f i sh ing gear than old f i s h wi th degenerate scutes. In th i s f ishery too, using a r e l a t i v e l y standard mesh gear, which i s d ic ta ted by the salmon f i she ry , the data from old ages where the f i s h are bigger than the gear's se lec t ion range are not w e l l represented. Random errors include sampling error and errors due to f luctuat ions i n the strength of the year c lasses . Phyca (1956) indicated that the white sturgeon of the Sacramento R ive r , C a l i f o r n i a , produced a strong year c lass at roughly an i n t e r v a l of ten years. To separate the t o t a l mor ta l i ty rate in to na tura l and f i s h i n g mor ta l i ty ra tes , i t was assumed that i n unfished condi t ion the sturgeon could l i v e to a maximum age of fo r ty , f o r t y - f i v e , and f i f t y years. Catch curves were accordingly constructed and t h e i r slopes used to estimate na tura l mor ta l i ty ra tes . The f i s h i n g mor ta l i ty rates were then obtained by subtract ing natural .morta l i ty estimate from the estimated t o t a l mor ta l i ty ra te . Theore t ica l y i e l d at d i f ferent rates of natura l and f i sh ing  mor t a l i t y To obtain the lengths used i n these c a l c u l a t i o n s , ca lcu la ted lengths for males and females were combined and a growth curve i n length on age constructed. The points were 23 smoothed out free hand and the length at d i f ferent ages obtained. For these lengths corresponding weights were calcula ted on the basis of the length/weight r e l a t i onsh ip . Since the equations representing the length/weight r e la t ionsh ips for males and females were much the same, any of them could be used for obtaining the weights at d i f ferent 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) out l ined i n Ricker (1958) for est imating equ i l ib r ium y i e l d was found to the the most appropriate for these computations, because growth i n the Fraser River white sturgeon does not conform to von Bertalanffy•s law of growth. The data presented cover a range of age from one to t h i r t y - s i x , wi th the corresponding length and weight in te rva l s of 9.0 to 71.7" and 0.154 to 106 pounds r e spec t ive ly . For these c a l c u l a t i o n s , na tura l mor ta l i ty rates of 0.05, 0.089, 0.10 were choseq and for each of these y i e ld s ca lcula ted for 0.025, 0.04, 0.05, 0.06, 0.075, 0.13, and 0.25 leve ls of f i sh ing mor t a l i t y . 24 RESULTS Age Determination Table I shows the resu l t s of the age determination, and F i g . 3 , the age composition for the Fraser River white sturgeon. The data on age composition do not include 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 years. Age group eleven dominated the catches, followed by age group th i r t een . Apparently the f ishery i s operating most e f f ec t i ve ly on age groups nine to s ix teen . 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 to 42". From the data, however, i t i s apparent that wi th in 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 su l t s i n an extensive overlapping of lengths of f i s h of d i f ferent age groups. Within length group 30 to 42", seventeen age groups are represented. Length, therefore, i s a poor index of age i n white sturgeon. Growth of the Fraser River white sturgeon 1. Growth i n length Table I I gives the average empi r ica l fork length at time of capture for the male and female sturgeon and the data are presented graphica l ly 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 S e r i a l Fork S e r i a l Fork S e r i a l Fork Number Length Age Number Length Age Number Length A8. e 214 12.0 4 12 33.0 13 138 36.5 11 216 12.0 4 160 33.0 10 186 37.0 10 217 13.0 3 134 33.5 11 152 37.0 10 218 13.0 5 224 33.5 12 74 37.5 10 240 13.0 5 163 33.5 10 112 37.5 12 212 14.0 4 246 34.0 13 115 38.0 13 211 14.5 7 225 34.0 12 44 38.0 16 121 15.0 6 233 34.0 11 40 38.0 12 213 15.0 4 222 34.0 16 17 38.5 15 196 15.0 4 137 34.0 14 151 38.5 11 202 15.5 6 142 34.0 12 168 39.0 11 210 16.5 7 246 34.0 13 95 41.0 16 239 17.0 10 16 34.0 15 41 41.0 10 198 18.5 9 250 34.0 9 126 41.5 12 200 19.5 10 88 34.0 12 24 42.0 19 118 21.5 5 S3 34.0 9 133 43.0 14 197 22.0 9 68 34.0 13 230 43.0 19 199 22.5 12 50 34.0 10 229 44.0 11 245 24.0 5 52: 34.0 10 184 45.5 16 117 24.0 9 32 34.0 11 130 45.5 10 241 24.5 6 43 34.0 12 106 46.0 16 116 29.0 8 36 34.0 11 91 47.0 43 194 29.0 10 174 34.0 16 150 48.0 11 23 30.5 7 149 34.0 10 89 48.0 18 236 30.5 14 21 34.0 12 155 48.5 15 231 31.0 8 223 34.5 16 93 50.0 16 143 31.5 8 190 34.5 12 255 53.0 24 114 31.0 9 109 35.0 12 166 57.0 20 66 31.0 9 64 35.0 13 254 59.0 24 19 31.0 12 175 35.0 10 252 59.0 24 234 31.5 23 173 35.0 16 139 62.0 22 251 31.5 _ _ 171 35.0 10 107 67.0 43 235 31.5 11 162 35.0 10 220 73.5 32 90 31.5 11 131 35.5 11 238 75.5 33 232 32.0 10 127 36.0 12 153 79.0 63 18 32.0 17 60 36.0 17 219 80.0 39 77 32.0 8 249 36.0 16 237 91.25 36 72 32.0 11 189 36.0 10 81 32.0 23 185 36.0 13 55 33.0 9 164 36.0 16 34 33.0 11 148 36.0 11 14 33.0 12 129 36.0 9 males Table I Length and age of the male and female white sturgeon of the Fraser River May 1 to October 28 1962 (continued) S e r i a l Fork S e r i a l Fork S e r i a l Fork Number Length Age Number Length Age Number Length Age 215 12.0 4 128 34.5 12 46 42.0 19 191 12.0 3 97 35.0 11 13 42.0 19 192 12.0 4 98 35.0 11 9 42.0 18 124 13.0 6 29 35.0 13 104 43.0 13 203 14.0 4 146 35.0 9 56 44.0 15 122 16.0 7 158 35.0 14 111 48.0 12 208 18.5 10 181 35.0 11 85 46.5 20 201 18.5 12 31 35.0 13 103 48.0 16 209 18.5 7 25 35.5 14 256 49.0 22 120 20.5 10 8 35.5 12 140 51.0 16 188 23.0 6 227 36.0 16 165 51.0 14 195 25.0 6 92 36.0 12 125 51.5 11 53 27.0 12 147 36.0 13 102 55.0 19 48 30.0 11 167 36.0 11 80 55.0 26 1 30.5 12 179 36.0 15 253 65.0 19 172 31.0 7 37 36.0 13 243 71.0 35 176 31.0 13 15 36.0 10 105 84.5 63 65 31.5 11 22 36.5 13 242 89.0 71 73 32.0 12 226 37.0 11 237 91.25 36 58 32.0 8 247 37.0 13 141 32.0 14 82 37.0 11 136 32.0 9 86 37.0 13 42 32.0 12 182 37.0 10 33 32.0 13 78 37.5 12 94 32.5 13 59 38.0 11 108 33.0 10 113 38.0 11 35 33.0 15 10 38.0 15 180 33.0 14 145 38.0 11 157 33.0 9 79 38.5 13 248 33.0 13 47 39.0 13 2 33.0 13 26 39.0 11 132 34.0 8 27 39.0 11 57 34.0 13 28 40.0 20 6 34.0 11 30 40.0 13 3 34.0 15 11 40.0 14 38 34.0 13 7 40.0 15 87 34.0 13 96 40.0 23 20 34.0 12 221 40.0 19 62 34.0 16 89 41.0 18 females 2 0 25 3 0 AGE IN YEARS Fig. 3 Age distribution in the Fraser River white sturgeon commercial c i tches 50 40 ™ 30 u. o LU cn X Z 20 10 0 0 O <M LO in ' ' ' 1 ^ . ' ' • • » ' • i» ~. ^ m /-I 3 6 — — r M . - M ( M f \ 4 o i f ^ r O(*)r») r<") •< TJ T T t i n r~h n r - i r 1 1 rn n CO rf m m 1 <o r> 0D 0 -1 «» i n u i co FORK LENGTH IN INCHES Fig 4 Length frequency distribution of the Fraser River wh : tu sti;!'aeon CO 29 s i m i l a r . They show a fast growth rate up to the tenth year, but thereafter the curves f l a t t en off suggesting a slower growth ra te . There i s i nd ica t ion that af ter the twentieth year of growth a faster growth rate i s r ev ived , but wi th 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 properly. 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 ca lcu la t ions are given i n Tables I I I and IV. These resu l t s indicate that growth i n length i n the white sturgeon i s very va r i ab l e . In the males, one-year-old f i s h varied between 4.6 to 14.4", ten-year-old f i s h between 21.5 to 40.2" , and the f i f teen-year -o ld 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 lec ted i n the growth of the females of which one-year-old f i s h var ied between 4.9 to 12.0", ten-year-old f i s h between 21.0 to 43.0" and f i f teen-year -o ld f i s h between 31.0 to 57.0". The growth of the i n d i v i d u a l f i s h i s a lso va r i ab l e . Some f i s h s tar t wi th a poor growth rate and maintain t h i s throughout the i r l i f e , while others show some compensation i n growth. Likewise, some f i s h which show a better growth i n t h e i r ear ly l i f e may maintain i t , while others show a poor growth rate i n the l a te r years. Calculated lengths do not show Lee's phenomenon (apparently slower growth rate at young ages of r e l a t i v e l y older f i s h ) . However, the reverse of Lee's phenomenon seems to be 30 Table II Average empirical fork length at time of capture for the male and female white sturgeon of the Fraser River, May 1 to October 28, 1962 Age Frequency Av.L. Range Age Frequency Av.L. Range 3 3 1 12.0 4 4 13~25 12.0-15.0 4 3 12.76 12.oIl4.0 5 1 13.00 5 •a 6 1 24.50 6 _ mm 7 2 22.50 14.5-30.5 7 2 25.00 18.5-31.5 8 6 28.75 16.5-32.5 8 2 33.00 32.0-33.0 9 8 29.81 18.5-36.0 9 4 34.13 32.5-36.0 10 16 35.68 19.5-45.5 10 4 31.25 18.5-37.0 11 16 34.92 31.5-44.0 11 15 37.07 31.0-51.5 12 13 35.12 31.0-41.5 12 10 32.50 18.5-44.0 13 8 36.69 32.5-47.0 13 15 36.30 33.0-43.0 14 4 35.13 33.0-40.0 14 6 37.42 32.0-51.0 15 6 37.08 32.0-48.5 15 5 35.50 30.5-44.0 16 9 39.56 34.0-50.0 16 4 41.25 30.0-48.0 17 2 34.00 32.0-36.0 17 _ mm 18 1 40.00 _ 18 2 41.50 41.0-42.0 19 2 42.50 42.0-43.0 19 4 47.25 40.0-65.0 20 3 45.67 32.0-57.0 20 2 43.25 40.0-46.5 21 _ _ 21 _ 22 1 62.00 22 1 47.00 23 2 39.75 31.5-48.0 23 2 36.00 32.0-40.0 24 2 59.00 59.0- 24 mm 25 _ _ mm 25 _ 26 _ — 26 1 55.00 32 1 73.5 35 1 71.00 — 35 1 75.5 36 1 91.25 43 1 67.0 — 63 1 81.00 mm 53 1 53.0 — 71 1 89.00 mm males females 10 15 20 25 30 35 40 45 AGE IN YEARS 50 55 60 65 LO Fig 5 Growth in length of the Fraser River male white sturgeon (Average empirical fork length by age groups) i_. 10 IS 20 25 30 35 40 45 50 55 60 65 7i AGE IN Y E A R S Fig.6 Growth in Length of the Fraser River female white sturgeon (Average empirical fork length by age groups ) 33 indica ted i n that there i s apparently a higher growth rate at the lower ages as calculated from older f i s h . This most probably r e su 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 resu l t s that both sexes have a rapid growth rate i n t h e i r f i r s t year which drops off rather r ap id ly i n the second year. Increments from age two to age s ixteen are uniform, averaging 2.34 inches per year. There i s no apparent difference i n the growth of the sexes at these ages. Af ter age s ix teen , however, s i gn i f i c an t differences are evident , the females growing much faster than the males. Curves of growth (F ig s .7 , 8) based on back calculated lengths, show that growth i n f i s h older than f i f t een years i s i r r egu la r showing periods of retarded growth followed by periods of accelerated growth. The r e su l t i ng 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 indicate that e i ther sex i s growing to a maximum s i z e . F igs . 9 and 10 show the Walford transformations for the males and females r espec t ive ly . In both cases these figures indicate that although the l i n e s approach the 45° diagonal , there i s no ind ica t ion that any of them w i l l cross i t , providing evidence that the white sturgeon does not grow to a f ixed maximum s i z e . Therefore the growth of the Fraser River sturgeon does not conform to von Ber ta lanffy ' s law of growth. Growth of the di f ferent year classes Fig.11 represents the growth i n length of the female year classes 1945, 1946, 1949, and 1950. These plots reveal some noticeable differences i n the growth rates of the di f ferent year Table III Back calculated lengths for the female sturgeon of the Fraser River — material collected between May 1 and October ;28 1962 sir 203 r 8, .8 J' 9. .4 "• 3 12. .5 - T 14 5 5 1 7 ""8" 195 9, .1 14. .8 17. .4 20, .4 23, .2 24, .0 49 8. .9 14. .8 17. ,2 21. .8 23, .8 28, .2 32. .1 33, .5 86 10. .2 13. .4 16. .5 20, .5 22. .6 24, .4 28, .5 31, .5 33, .7 36.6 Ul 9. .8 12. .0 15. .5 16, ,7 20. .8 22. .8 25. .4 27, ,5 2S, .6 29.7 59 7, .8 12, .8 15. ,6 18. .8 22. .2 25, .9 27. .4 29. .9 32, ,5 34.5 78 7. .5 10, .8 12. ,6 15. .5 16. ,2 17, .2 19, .4 26. .1 28. ,5 32.5 29 7. .3 11, .9 14, .4 15. .8 17. ,2 22, .2 26. .4 25, .8 31, ,8 33.3 31 9. ,6 12, .2 15. .2 17. .6 19. ,7 22, .7 25. ,7 28. .1 29. ,8 31.8 227 9. .4 12, .5 13. 8 15. .2 18. .0 19, .5 21. ,7 23. ,5 27. ,3 30.0 182 10. ,0 13. .4 16. .1 18. ,0 19. .0 21, ,8 24. ,1 27. .0 30. ,0 32.1 144 8. ,0 9. .9 12. 3 13. ,8 14. ,8 15, ,8 16. ,5 19. ,6 22. .7 24.8 6 4. ,9 6. .8 11. .7 12. ,2 13. .8 14, .2 16. ,3 18. ,a 22. ,8 25.E 35 6. ,7 10. ,7 11. .9 15. .3 20. ,0 20, ,6 21. .8 23. .6 26. 4 29.2 165 14. .3 16. .9 18. .5 21, .8 25, .8 31, .8 34, .2 38, ,4 40, .9 43.2 167 9. .4 15. .5 15. .8 18. ,0 20. .6 22, .3 24, .3 26, .3 28. .0 29.7 226 6. .2 9, .5 10. .4 11, .0 12. .0 14. .5 16, .5 19, ,8 24. ,6 27.2 11 8. .8 12, .4 15. ,1 17. ,0 18. .1 21, .2 22, .3 23, .6 28. ,9 30.1 128 9. ,4 11, .8 14. 0 15. ,5 16. .5 18, .3 19, .6 22, .6 23. .8 25.4 140 10. .4 15, .1 17. ,2 .19, ,8 23. .2 2S, .6 30, .9 32, .7 34. ,8 37.4 37 7. ,0 10, .4 12. .6 13, .7 16. ,7 17, .3 17, .6 20. ,0 20. .7 25.3 13 6. .3 10. .2 14. ,6 17. ,8 21. ,3 22, .4 24. .3 25. .8 26. .0 29.8 9 5. .5 9. .5 11. ,5' 13. .2 15. .8 16, ,7 18. .0 20. .3 21. .9 23.8 46 9. .5 10, .0 11. ,0 13. .8 16. .1 17, .1 13, .6 19. .0 20. ,1 21.0 253 11. .2 15, .7 18. .7 19. ,7 22. .2 24. .9 27. .0 31. .8 38. ,6 41.7 96 7. ,2 12. .0 12. ,5 15. ,2 15. .6 16, ,0 17. ,3 18. ,4 21. ,3 24.5 243 9. ,3 12. .8 14. ,0 17. ,0 19. .1 25, ,9 26. ,4 23. ,5 30. .1 31.7 237 12. .0 14. ,0 15. .4 17. .8 19. .8 22, ,0 24. ,6 25. ,0 26. .0 29.4 31.4 37.8 36.4 34.7 33.7 34.2 34.7 27.4 27.4 30.1 45.8 31.0 30.6 32.1 27.0 40.1 26.9 31.0 25.4 21.4 44.9 25.2 25.6 28.8 30.1 31.4 32.4 33.6 35.0 37.3 36.0 38.8 33.6 34.6 35.4 37.8 38.8 40.6 43.0 44.2 47.1 46.0 4i.fi 51.1 52.8 53.8 54.6 55.1 57.2 60.1 61.4 63.0 64.6 66.1 67 6 69 5 70 6 32.4 32.4 36.5 40.0 43.7 47.4 51.6 54.E 57.5 60.0 62.5 64.7 66.5 68.5 70.0 71.7 73.2 75.5 77.6 6-.4 82.0 84.0 86.0 89.0 89.2 36. .7 37. .0 30. .5 31. .4 34. .0 30. .6 33. ,0 49; .7 50, .4 33, .4 34, .9 33. .6 34, 6 37. .5 39. 2 40. ,0 2£. .5 29. ,4 31, .4 32. .6 34, .5 43. .2 4V ,E 47. .3 50. .0 55, Ll 27. .8 29. .5 32, ,3 33. .5 35, .0 36, .0 32. .3 34, ,2 25, ,7 36. ,4 35 .0 41, .7 27. ;5 29. ,2 31. ,8 34, .3 35, .8 39, .1 41.1 25. ,0 26. ,2 27. ,5 • 31. .3 33, .2 35, ,3 37.£ 41.9 47. .6 45. ,9 53. 6 57. .2 60, .0 • 62, .4 64,0 64.6 .  . . , . ,  . . . . , . . , ,. . . , . . , , , , .  34, 15 35. 90 37. ,38 35. .29 41. .31 43. ,06 46.43 50.18 Average B.73 12.17 14.42 16.66 19.40 21.42 23.34 25.81 28.09 30.42 32.30 .1  .  . £ 9.  .  .  .  .  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 material collected between Kay 1 and October 28, 1962 sir- 1 2 3 Z T" 4 7 5 10' U VI IT 15 213 8.2 10.2 13. .1 15 .0 193 6.2 10.4 11. .2 12, .3 12. .9 15, .5 23 6.6 11.5 12. .6 18, .2 22. .9 27, .2 30.5 77 7.3 11.2 13, .5 15 .2 17, .3 20, .2 24.2 31, .6 210 6.8 8 . 9 9, .5 11, .0 11. .8 12, ,4 13.8 16. .0 197 10.2 11.0 11. .9 15, .0 16. .0 17, ,4 20.0 20, .8 21, .6 83 8 .2 12.3 16. .0 18. .0 19. .3 23, .7 27.3 32. .3 33, .6 231 7.5 11.5 13, ,9 16. .2 19. .2 22, .5 26.2 30. .0 31. .0 162 6 .2 11.2 12. .6 15, .0 17. .4 19, .6 25.4 2S. .2 31. .4 35. .0 171 4.6 8 .4 11. ,3 13, .2 19. .1 23, ,0 25.6 28. ,5 29. .8 35. .0 232 8 .4 10.6 12. .6 16. .0 17, .0 19, .4 22.5 27. .8 27, .8 32, .0 186 6.7 12.6 15. .8 19. .6 21. .6 23. .2 26.6 30. .5 33, .5 37. .0 228 10.3 14.6 17. .5 19. .8 23. .3 27. .2 28.2 30. .3 32. .8 33. .0 163 8 .8 11.4 13. .0 15, .8 18. .4 19, .6 24.4 29. .2 30. .2 33. .0 149 10.2 14.7 16. .6 22. .8 24. ,4 27. .0 29.4 32. .5 35. ,3 39. .6 50 8.5 11.1 13. .7 18. .4 19. ,4 20, .7 26.2 29. ,4 31. .0 33. ,6 34 5.0 6 .3 7, .6 12. .8 17. . 9 . 20. .0 21.> 25, .9-. 27. .1; 29, .8" 32. .6. 233 8 .9 14.2 17, .8 19, .0 21. .4 23 .6 26.0 28. .5 31. .0 33, .0 34, .0 175 8.5 12.6 15. .0 17, .0 19. .0 20, ,4 23.4 25. .5 28, .8 30. .8 31. .9 229 8.2 13.3 15. .1 17, .4 21. .0 23, .7 23.9 31. .6 35. .7 39. ,2 40. .6 148 10.0 14.0 16. 8 19, ,2 21. ,2 23. .1 24.6 27. .1 29. .4 31. ,0 34. .1 151 9 .8 14.5 17. ,1 21. .2 25. .1 27. .1 29.8 31. ,2 33. .2 35. .8 38. .5 14 5 .9 7.6 10. .  14, .2 18. .3 19, .8 21.1 23. .4 24. .6 28, .0 29. .0 30, .6 40 8 .9 11.7 15, .2 16. .2 19. .6 23, .0 25.0 26. .9 29. .4 31. .2 •34, .0 38. .0 36 4.9 9 .9 11, .5 13. .0 16. .6 20. .0 21.0 21. ,2 24. .4 25. .8 28. ,2 31, .0 127 9.5 14.1 16, .0 17. .4 19. .6 21, .0 23.5 23. .9 26. .1 23. .7 31. .5 35 .7 12 7.7 12.0 13, ,4 15, .8 17. .4 19. .6 21.1 23. .2 24. .4 26. .6 28, .1 29. .3 33. .0 91 6.9 9 .7 15. .4 20. .6 25. ,8 27, .4 30.6 32. .6 34. ,6 36. ,7 39. .5 41. .6 45. .2 154 9.4 12.8 13. .6 14. .6 15. .6 16, .2 18.0 20. .2 21. .4 21. .6 26. .0 28. .2 31. .0 33. .9 133 6.8 9 .6 11. .8 12. .5 17, .0 22 .2 25.8 29. .8 32. .8 35, .1 37, .6 36. .6 40, .8 42. .3 183 9.1 11.4 12. .© 14. .0 14. .9 18. .4 20.8 23. .0 24, .2 25, .4 26. .6 31. .8 34, .1 35. .7 37. .0 95 9.1 11.9 14, .0 15, .0 16. .4 17. ,1 18.5 21. .4 27. ;5 31, .1 34. .0 36. ,4 38 .8 39, .2 41. .0 184 9 .3 13.6 14. ,5 18. .9 25. ,2 26, .8 31.7 34, .9 35. .9 36. .8 37. ,8 40. .4 41, .9 43, ,4 45. ,4 45, ,5 93 9 .6 ol.4 15. ,6 19, .3 22. ,2 25. .4 29.1 32. .1 33. ,7 35. ,0 37. .0 39. .4 43, .0 45, .5 48. .2 50. ,0 106 8.9 10.6 15. ,5 17, .5 20. ,3 21, .9 23.4 25. .8 28. .8 30. ,2 31. ,2 33. .4 37, .8 40. ,2 45. .5 46. .0 164 9.8 10.6 11. .2 12 .3 14. .7 15, .3 16.6 18. .6 19. .6 21. .5 22, .6 24. .8 27 .0 2E, .2 29. .6 31, .2 24 14.0 16.1 16. ,4 20, .1 20. .9 21, .4 22.5 23, .6 26. .0 27. ,0 28. .8 30. .4 32. .4 34. .2 35. .6 37. .9 230 7.9 12.8 15, .0 16. .1 17. .4 18. .8 19.4 20. .4 22. .7 24. .8 26. ,7 29. .0 31, .4 33, .3 35. ,0 37. L 166 10.6 14.0 15. .3 16. .2 19. . 5 - 20, .8 22.6 25. ,8 28. ,7 30. .9 34. .6 37, .2 35, .8 43. .0 44. ,7 46. .5 -252 14.4 19.1 22, ,0 25,9 31. ,5 32. 8 35.6 ii. .8 39. .8 40. .2 41. ,8 42. .2 44. ,1 46. .8 48. 5 49. ,2 219 6.2 8.5 20. 1 22. .6 24. 5 29. ,4 32.0 33. ,4 34. 6 35. 8 36. 8 37. .2 37, ,6 38. 8 40. e 42. ,4 153 18. .2 19. ,0 20.3 21. 2 21. .7 22. 2 22, .7 23. .6 24. .7 25. 2 25. 5 26. ,4 Average 8.44 11.80 14. ,36 16. .84 19. ,45 21. ,83 24.10 27. .08 29. ,25 31. 50 32. .93 33. .94 36. .29 37. ,71 39. 42 41. ,33 3o 31 52 33 34 35 34.L 36.0 3£.6 3S.9 42.0 35.4 41.6 43.0 50.3 52.8 56.2 51.4 52.8 54.7 55.8 56.6 5S.0 59.0 45.2 49.8 53.8 56.2 58.0 60.4 63.4 67.0 68.6 70.0 71.0 72.0 79.0 74.9 75.2 75.8 76.6 77.6 78.0 78.4 27.9 28.S 29.6 30.1 31.5 32.7 33.2 34.0 35.1 35.8 37.2 37.4 39.2 41.6 42.9 44.9 4G.6 47.8 49.1 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 YEARS Fig 7. Growth in length of the female Fraser River White sturgeon (Average calculated fork length by age groups) e 4 o o o o o o o o o o o o 9 o o o o o o o e o 0 o e o o o o o o o o 5 10 15 2 0 2 5 3 0 3 5 AGE IN YEARS Fig 8. Growth in length of the male Fraser River white sturgton (Average calculated fork length by age groups). 38 L E N G T H A T T I M E T Firj 9 W a l f o r d t r a n s f o r m a t i o n of ca lcu la ted lengths of the Fraser River ma le white sturgeon. 39 LENGTH AT TIME T Fig IQ Walford transformation of calculated lengthsof Fraser River female white sturgeon. c lasses . Year c lass 1945 had a slow growth ra te . ' From 1947 to 1951, there was only a s l i gh t difference between the length of the f i s h of the 1945 year class arid the length of the 1946 year c l a s s . Af te r 1961, f i s h of year c lass 1946 exceeded i n length f i sh of the 1945 year c l a s s . In 1960 f i s h of the year c lass 1949 were of the same length as f i s h of the year c lass 1945 i n spi te of the fact that the l a t t e r were four years o lder . Af ter 1960, f i s h of the 1949 year c lass at tained greater lengths than those of the 1945 year c l a s s . In the males ( F i g . 12) s im i l a r differences i n the growth of the year classes are exhib i ted . F i sh of the year class 1950 were exceeded i n length by f i s h of the 1951 year c lass i n the eighth year of l i f e and by f i s h of the 1952 year c lass i n the tenth year of l i f e . Analys is of growth i n the di f ferent calendar years was attempted. The r e s u l t s , however, did not show a de f in 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 lso resu l t from the differences i n the growth rates of the year c lasses . Rela t ionship between s ize and growth i n the different year classes F ig s . 13 and 14 represent the re la t ionsh ips between s i ze and growth i n the di f ferent year c lasses . These graphs show that the instantaneous growth rate declines as the f i s h increase i n s i ze which i s as expected. However, they a lso ind ica te that growth poten t ia l s at the di f ferent s izes are va r i ab l e . This may be due s t r i c t l y to sampling e r ro r , but may 50 L 1945 '46 V '48 'Aa '50 ' 5l '52 '53 '54 '55 '56 '57 '58 '59 '60 '61 '62 CALENDAR YEARS Fig 11 Calculated growth histories of the year classes of the female Fraser River white sturgeon-CO o CD z U J 1949 50 '51 '52 *53 '54 '55 '56 '57 '56 "59 '60 '61 %2 CALENL.AR YEAR Fig 12 Calculated growth histories of the year classes of the Fraser River male white sturgeon U J 25 i— < cm year class 1946 year class 1945 J 20 o oc o co 15 O UJ 1 0 < i— 0 Fig 13 10 35 AO 15 20 25 30 FORK L E N G T H IN INCHES Relationship between size and growth of the different female year c lasses . 45 year class 1943 5 IO 15 20 25 3 0 35 4 0 45 FORK L E N G T H IN INCHES Fig 14 Relationship between size and growth of the different male year classes. a l so indicate changes i n the feeding behaviour of the f i s h ; for example, a change from an insectivorous to a piscivorous d i e t , or changes i n the abundance of food consequent to changes i n the na tura 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 lso contribute to these va r i a t i ons . Trends i n the growth of the year classes i n the d i f ferent calendar years were not revealed by th i s method. These trends may ex is t but due to scanty data, i t i s d i f f i c u l t to br ing 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 River white sturgeon. The data are presented graph ica l ly i n F i g s . 15 and 16. The data show that growth i n weight, l i k e growth i n length, i s characterised by great v a r i a t i o n s . Weights w i th in age groups vary so much that weight, l i k e length, 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. After 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 een the increments i n weight seem to be very h igh , but due to scanty data t h i s i s not w e l l represented on the graphs. 46 Table V Average empirical weight for male arid female white sturgeon of the Fraser River, May 1 to October 28, 1962 Age Frequency Av.W. Range Age Frequency Ay.W. Range 3 1 0.50 3 — mm 4 5 0.51 0.39- 0.64 4 — mm mm 5 3 1.50 0.50- 2.50 5 — 6 4 1.43 0.71- 3.25 6 3 3.67 3.00- 4.00 7 2 4,29 0.52- 8.00 7 3 3.50 1.00- 8.00 8 7 4.83 0.97-11.00 8 2 8.50 7.00- 8.00 9 12 8.83 1.50-11.00 9 3 9.83 9.00- 10.50 10 19 9.41 1.00-20.00 10 5 7.70 1.50-14.25 11 16 10.44 7.00-17.00 11 14 14.47 8.00-38.00 12 13 11.04 7.75-19.50 12 10 11.40 1.25-29.25 13 9 14.50 8.50-33.50 13 17 12.60 8.00-27.00 14 6 12.57 7.50-23.00 14 7 13.07 8.00-31.00 15 5 14.58 9.00-31.00 15 8 13.13 7.00-26.00 16 8 22,31 9.00-44.50 16 5 14.30 7.00-29.00 17 3 11.58 8.75-15.00 17 mm — 18 1 10.50 — 18 2 19.42 17.33-21.50 19 2 20.50 19.25-21.75 19 5 32.90 15.00-72.00 20 3 33.00 9.00-56.00 20 3 26.92 15.00-35.00 21 _ 21 — — 22 1 67.00 22 1 28.00 23 3 14.58 7.75-26.00 23 mm 24 2 49.00 46.00-52.00 24 mm mm 25 _ mm _ 25 mm mm 26 _ mm mm 26 1 45.00 32 1 95.25 mm 32 mm mm 33 1 124.0 mm 33 mm — 35 _ mm 35 1 110.0 — 36 _ _ mm 36 1 218.0 mm 39 1 110.0 mm 39 mm mm 43 1 115.0 mm 43 mm mm 53 1 35.00 mm 53 mm mm 63 1 132.0 mm 63 1 342.0 71 _ mm 71 1 173.0 males females 180 e o 0 0 9 ° 0 5 10 15 20 25 30 35 AO 45 50 55 60 A G E IN Y E A R S Fig15. Growth in weight of the Fraser River male white sturgeon (Average weight by age groups ) 65 48 0 Fig 16 15 20 25 A G E IN Y E A R S Growth in weight of the Fraser River f e m a l e white sturgeon (Average weight by age g r o u p s ) 49 Length/weight re la t ionsh ips F i g . 17 shows the logari thmic plots of weight against length for the Fraser River white, sturgeon. Regression l ines f i t t e d on these plots by the method of least squares are LoggW = -8.73 + 3.13 Log e L for the male LogeW = -8.79 + 3.15 Log e L for the female 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 s i m i l a r . 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 he i r increments i n weight are much larger than those of males due to the expansion of the ovar ies . This would give the equation for the females a much higher slope than that for the males. Table VI gives the average and calcula ted weights at d i f ferent lengths, and the data are presented graphica l ly i n F i g . 18. From th i s table and graph, i t i s evident that growth i n weight i n both sexes i s s im i l a r u n t i l the f i s h a t t a in 30" i n fork length. After t h i s length, the females add on more weight than the males for the same increment i n length. The difference i n weight increments becomes progress ively bigger as the f i s h increase t h e i r s i ze i n length. 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 ferent ages were used to ca lcu la te the 50 Table VI Comparison between empirical average weight and calculated weight for male and female white sturgeon of the Fraser River May 1 to October 28 Average Calculated Average Caleulated Length Weight Weight Weight Weight 12" 0.42 ! 0.384 0.40 0.384 13 0.53 0.494 0.33 0.486 14 0.58 0.625 0.57 0.619 15 0.72 0.774 _ _ mm mm 16 _ _ mm mm 1.00 0.942 17 1.00 1.15 mm mm 21 2.00 2.22 22 2.00 2.56 _ mm mm mm 23 mm mm 3.00 2.91 24 4.00 3.38 mm mm 29 5.75 6.10 9.00 6.25 30 — _ _ 7.00 6.79 31 7.50 7.51 11.00 7.51 32 10.56 8.30 8.52 8.38 33 8.96 9.17 8.43 9.26 34 10.16 10.10 10.06 10.20 35 11.57 11.00 11.00 11.10 36 12.13 11.90 11.66 12.20 37 14.33 13.10 13.45 13.20 38 14.00 14.30 13.21 14.40 39 17.00 15.50 15.25 15.60 40 _ _ _ _ 16.63 16.90 41 20.00 18.00 21.50 18.30 42 19.25 19.40 16.11 19.60 43 22.38 20.90 27.00 21.30 44 22.50 22.40 27.63 22.80 46 45.00 25.70 mm mm mm mm 47 33.60 27.60 mm mm mm mm 48 29.00 29.90 49 _ _ 28.00 32.00 50 44.50 33.30 _ _ mm mm 51 . _ _ mm mm 36.50 36.50 53 35.00 40.30 mm mm mm mm 55 — — mm mm 45.00 46.00 57 56.00 50.40 59 49.00 56.10 — males females 51 30 iO 50 60 70 10 FORK L E N G T H IN 20 30 iO 50 60 N C H E S Fig 17. Length-weight relat ionship for the Fraser River wnite stjrgecn 52 Fig 18. 10 2 0 3 0 4 0 5 0 FORK L E N G T H IN I N C H E S Growth in we igh t of t he F r o s e r R i v e r wh i te s tu rgeon c a l c u l a t e d w e i g h t s at d i f f e r e n t lengths. 53 180 160 140 120 cn Q § 100 o a. 80 x o £ 60 40 20 • 0 o O O P • 9 o 30 35 5 10 15 20 25 AGE IN Y E A R S Fig 19. Growth in weight of the Fraser River white sturgeon calculated weights at different age?. 54 corresponding weights. The calculated weights obtained by the equations representing 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 empirical weights at lower lengths. These differences, however, can be expected. They a r i s e from the v a r i a b i l i t y in weight observed at the d i f f e r e n t length groups and from the fact that at some length groups only a few specimens are represented. At higher lengths there are b i g differences between the calculated weights and the average empirical weights. As the sturgeon grow older and increase in length the corresponding increments in weight assume another pattern. The length/weight re l a t i o n s h i p at these higher lengths should therefore be represented by another equation. Age at f i r s t spawning and in t e r v a l s between spawnings Tables VII and VIII give the r e s u l t s of examination of the f i r s t f i n ray sections for age at f i r s t spawning and intervals between spawnings. From Table VII i t w i l l be observed that in males spawning "belts" were not observed i n a l l f i s h i d e n t i f i e d as mature. 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 " at age eight to eleven, and nine to eleven which would suggest that the f i s h spawned for the f i r s t time at about age eleven. However, f i s h much older than eleven years, eg. sixteen, nineteen, twenty-three and twenty-four year old f i s h showed no formation of crowded annuli which would suggest that they had not spawned yet. These data suggest that the male white sturgeon of the Fraser River, 55 Table VII Age at f i r s t spawning and subsequent spawnings in the Fraser River white sturgeon (males) S e r i a l Fork Spawning Belt Number Length Weight Age 1st 2nd 3rd 4th 238 75.5 124 33 19-22 24-27 27-31 139 51.0 67 22 16-18 — — — _ — — 220 73.5 95.25 32 9 -11 14-16 19-22 30 184 45.5 26.0 16 8 -11 not d i s t i n c t — mm 219 80.0 110.0 39 10-15 not d i s t i n c t mm mm 107 67.0 115.0 43 11-14 18-22 28-33 106 48.0 45.0 16 —— — — —— 91 47.6 33.5 13 — — — — mm mm 252 59.0 52.0 24 Progressive crowding , after 9 93 50.0 44.5 16 «. _ — — _ — _ — 230 41.0 21.75 19 mm mm — _ _ _ _ _ 229 42.0 22.50 11 mm mm — — — — _ — 95 41.0 20.0 16 mm mm —— —— — — 244 48.0 26.0 23 mm mm — — — — —— 255 53.0 35.0 24 mm mm — — — — — _ Table VIII Age at f i r s t spawning and subsequent spawnings in the Fraser River white sturgeon (females) S e r i a l Fork Spawning Belt Number Length Weight Age 1st 2nd 3rd 4th 253 65.0 72.0 19 46 42.0 16.0 19 mm mm _ _ _ _ ^ mm 105 84.5 342.0 63 25-33 36-40 46-49 --103 48.0 29.0 16 — _ _ _ _ _ _ — 102 55.0 45.0 20 18 — — — — — — 140 51.0 36.5 16 — _ — — — _ _ _ 243 71.0 110.0 35 20-26 _ _ — _ — — 242 89.0 173.0 71 6-28 not clear 256 49.0 28.0 22 _ _ — — _ _ _ 29 35.0 14.0 11 _ _ — — _ _ — — 82 37.0 15.0 13 — — — — — — — — 20 34.0 10.5 13 — — _ — _ _ — — 125 51.5 38.0 11 — — _ _ — _ — _ 92 36.0 12.5 16 — _ - - — - - — . 113 38.0 13.5 15 — _ — — — _ — — 237 91.25 218 36 34 — — — _ — — K2 64.5 80 33 21-28 — — — — — — 56 s ta 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 igs . 7, 8) constructed from back-ca lcula ted lengths are e r r a t i c around age ten to th i r t een . There i s some decl ine i n the growth rate from age ten, and a r e v i v a l of growth after age th i r t een . These i r r e g u l a r i t i e s are repeated at age sixteen 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 pa r t ly be due to sampling error because only a few specimens were averaged at these ages, those at ages ten to th i r t een , and sixteen to eighteen, may be interpreted as i n d i c a t i n g decelerat ion i n the growth rate during the period of gonad maturation. In the female the sample i s so small that f luctuat ions i n the growth curve could be wholly due to i n s u f f i c i e n t data. I f i t i s assumed that the f i s h resumes normal growth i n the year immediately fo l lowing 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 ive years after 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 after 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 ixteen — f ive years l a t e r . It spawned a t h i r d time i n i t s twenty-second year af ter 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 sect ion showed that re tardat ion i n growth s tar ted i n i t s t h i r t i e t h 57 year. If 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 fourth spawnings at ten years. Specimen No. 107 f i r s t spawned when i t was fourteen years old and d id 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 - th ree and a fourth time at the age of fo r ty . These data then show that i n the Fraser River white sturgeon the reproductive cycle var ies i n the di f ferent 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 af ter an i n t e r v a l of f ive years while others take as long as ten years. In females, sections did not show subsequent spawnings c l e a r l y . Specimen No. 105 spawned a second time at the age of f o r t y , seven years af ter the f i r s t spawning. The duration between the second and t h i r d spawnings was nine years. After t h i s spawning the annul i are d i f f i c u l t to in t e rp re t , but i t seems that durations were shorter . Specimen No. 243 showed no formation of a spawning "bel t" nine years af ter 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 rates i n the Fraser River white Sturgeon In F i g . 20 i s shown the catch curve for the Fraser River white sturgeon. I t w i l l be noted that there i s a cer ta in amount of scat ter 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 U J < o in o o o r ut CD Z Fig 20. 20 25 "35" AGE IN YEARS Catch curve for the Fraser River white sturgeon 00 se l ec t ive at length 32 to 42" which corresponds to f i s h between nine and s ixteen years o l d . The sturgeon then:, i s p a r t i a l l y recru i ted in to the f ishery at age nine and i s most vulnerable to the f i s h i n g gear (and hence completely recrui ted) at age eleven. The mor ta l i ty rate determined by th i s catch curve does not represent the mor ta l i ty rate occurring i n f i s h younger than eleven years. The t o t a l ar i thmetic mor ta l i ty rate between ages eleven and twenty-seven i s 0.197 wi th a corresponding instantaneous mor ta l i ty rate of 0.219. At t h i s rate 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 ishery after a period of s ixteen years. Assuming that i f unfished, the sturgeon could l i v e to a maximum of for ty years , we obtain an instantaneous natura l mor ta l i ty ra te of 0.119 The difference between th i s estimate and the instantaneous t o t a l mor ta l i ty obtained i n the above estimate gives an instantaneous f i s h i n g mor ta l i ty rate of 0.100. Likewise, 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 years, we obtain instantaneous natural mor ta l i ty estimates of 0.101 and 0.089, and the instantaneous f i sh ing mor ta l i ty rates of 0.118 and 0.130. That i n an unexploited condi t ion 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 older than f i f t y years have been frequently taken i n various places - - Sunde (1961) i n three years ' c o l l e c t i o n from the Nelson R ive r , obtained over t h i r t y f i s h over f i f t y years old and i n the present c o l l e c t i o n from the Fraser River 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 m o r t a l i t y 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 , n a t u r a l m o r t a l i t y c o n t r i b u t e s o n l y a s m a l l f r a c t i o n . T h e o r e t i c a l y i e l d a t 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  m o r t a l i t y F i g . 2,1 shows p l o t s of y i e l d from t h e d i f f e r e n t c o m b i n a t i o n s of n a t u r a l f i s h i n g m o r t a l i t y . I t w i l l be observed from t h e s e p l o t s t h a t y i e l d d e c r e a s e s i n a b s o l u t e v a l u e as the n a t u r a l m o r t a l i t y i n c r e a s e s . W i t h a h i g h r a t e of n a t u r a l m o r t a l i t y , a maximum y i e l d i s o b t a i n e d by i n c r e a s i n g the r a t e of 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 i n w e i g h t a t t h e i n c r e a s e d r a t e of f i s h i n g m o r t a l i t y , i s much lower than i n a c o m b i n a t i o n o f b o t h 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 r a t e s . In F i g . 2 2 , y i e l d s a t s t a b i l i z e d r a t e s of f i s h i n g but v a r i a b l e r a t e s of n a t u r a l m o r t a l i t y a r e p l o t t e d a g a i n s t age. These p l o t s r e v e a l t h a t w i t h i n c r e a s i n g n a t u r a l m o r t a l i t y , t h e age a t w h i c h a maximum i s o b t a i n e d i s lowered. T h i s i s because i f n a t u r a l m o r t a l i t y i s h i g h i n any y e a r c l a s s , a t o l d age t h e r e a r e o n l y a few s u r v i v o r s whose i n c r e a s e i n w e i g h t may not be b i g enough t o make up f o r the l o s s i n numbers. T h e r e f o r e , to maximize y i e l d f i s h i n g s h o u l d s t a r t e a r l y enough b e f o r e t h e number of f i s h i n a y e a r c l a s s has been g r e a t l y r e d u c e d . A l t h o u g h t h e f i s h may be s m a l l i n s i z e a t t h i s e a r l y age, the number caught w i l l be b i g enough t o c o n t r i b u t e a b i g g e r y i e l d i n w e i g h t . Where n a t u r a l m o r t a l i t y i s low, a l a r g e r number of f i s h i n 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 growth a t t a i n s a b i g g e r w e i g h t . Thus the l o s s i n number i s more than compensated f o r by t h e g a i n 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 thus t h e 8000 I FISHING MORTALITY RATE Fig 21. Yield in weight at different rates of f ishing and natural mortality 63 whole stock. I t i s obvious, therefore, that i n s tocks, l i k e that of the sturgeon, where natura l mor ta l i ty 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 old age. In Table IX i s summarised the y i e l d at d i f ferent combinations of f i sh ing a natura l mor t a l i t y . Table IX Y i e l d at d i f ferent leve ls of f i s h i n g a na tura l mor ta l i ty using R i c k e r ' s method of estimating equ i l ib r ium y le Id ( y i e l d in: uni t s of weight) F i sh ing M o r t a l i t y Maximum Y i e l d Age Natural Mor 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 25 23 19 19 16 11 26 24 21 no maximum Natural Mor t a l i t y = 0.089 0.025 0.04 0.05 0.06 0.075 0.13 0.25 130 157 172 182 209 233 19 16 15 13 10 9 no maximum Natural 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 no maximum 109 138 165 179 194 214 15 15 13 12 10 9 15 64 I t i s ev ident from t h i s t a b l e tha 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 there i s an i n c r e a s e i n the y i e l d . Th i s increa se 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 increa se i n the f i s h i n g m o r t a l i t y . For example, 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 from 0.06 to 0.13 (53,837 0 increase) the increa se 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 that w i t h increa sed f i s h i n g m o r t a l i t y the f i s h e r y begins t o u t i l i z e f i s h from the young age group which may lead t o the d e p l e t i o n of the s t o c k s . The food of the Fra ser R i v e r whi te sturgeons R e s u l t s of the examinat ion of the stomach contents of the Fra se r R i v e r w h i t e s turgeon show that i t feeds on a wide range of food i t ems . Stomachs taken i n May show that eulachons formed the main i tem of the d i e t d u r i n g t h i s p e r i o d . The f ac t tha t most of the eulachons were p u t r i f y i n g i n d i c a t e s tha t the sturgeon i s a scavenger and feeds main ly on the dead ones. The q u a n t i t y of eulachons taken i s b i g , and fisherjnen s e l l i n g t h e i r c a t c h ungutted a t t h i s t ime lo se two pounds on each f i s h which i s reckoned t o be the weight of eulachons i n the 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 sturgeon were observed. The occurrence of young s turgeon i n one of the stomachs needs more data before we can conclude that i t i s h a b i t u a l f o r the w h i t e sturgeon t o feed on i t s young. I t i s probable that these were swept i n t o the mouth as the sturgeon i n d i s c r i m i n a t e l y scooped the bottom f o r food . Of the other three types of f i s h observed, the s c u l p i n s were the most f requent . I t i s probable that o ther types of f i s h 65 are eaten but some of the stomach contents were so f a r d ige s ted t h a t proper i d e n t i f i c a t i o n cou ld not be made. F i s h occurred i n f o r t y - t h r e e or 48.68?0 of the stomachs tha t had food , but were more frequent i n the b igger specimens. Of the i n v e r t e b r a t e s e a t e n , Chironomid l a rvae formed the b igges t s i n g l e group. They were recorded i n t h i r t y - o n e stomachs or 35.2370 and were eaten by both o l d and young f i s h . C r a y f i s h , s t o n e f l y l a rvae and a few Ephemeroptera l a rvae were observed i n s e v e r a l stomachs. C r a y f i s h were recorded only from f i s h b igger than 3 0 " , but the o ther two groups were eaten 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 , Daphnia , and a few copepods were r e c o r d e d . Some green vegetable matter 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 tha t these are taken i n c i d e n t a l l y w i t h o ther food i t ems . D e t r i t u s and p ieces of wood were present i n s e v e r a l stomachs. Whi l e the sturgeon 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 ieces 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 food . Harkness (1923) found t h a t Chironomidae l a rvae ( m i l g e s ) , mol luscs and Ephemeridae nymphs were the b a s i c food supply of the lake sturgeon i n N i p i g o n Lake. T r i c h o p t e r a l a rvae formed an important pa r t of the d i e t where they occurred i n great numbers. Harkness observed that i n some areas where other organisms such as Decapoda, A n i s o p t e r a , and Amphipoda occurred i n great numbers and were more e a s i l y o b t a i n a b l e the s turgeon fed on these and the amount of the otherwise s t a b l e d i e t became 6 6 p r a c t i c a l l y n e g l i g i b l e . 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 ea s i l y obtainable food w i l l come f i r s t regardless of i t s nature. F i s h , which form an important item i n the die t of the Fraser River 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 die t of the lake sturgeon i n Lake Winnibago, and noted that i n the smaller lakes mayflies and aquatic isopods were frequently taken. F i sh were only occas ional ly recorded, and these appeared to be discarded bai 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 species. F i sh 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 f i s h eaten. 67 DISCUSSION Age for the Fraser River white sturgeon was determined from sections of the f i r s t pectoral f i n rays . 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 contr ibut ions of other workers (Holzmayer 1924, Probost and Cooper 1954). Age analyses revealed that the f i shery was most e f fec t ive between age groups nine to sixteen and age group eleven, predominated the catches followed by age group t h i r t e en . 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 ix ty- three 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 natura l mor ta l i ty among the old f i s h at least i s rather low. High f i sh ing mor ta l i ty i s indicated by the predominance of young age groups i n the commercial catches. The analysis of growth i n length of the Fraser River white sturgeon has shown that growth i s very va r i ab l e . This v a r i a b i l i t y i s exhibi ted i n the growth of the i n d i v i d u a l f i s h w i t h i n age groups, and i n the growth of the di f ferent year c lasses . I t must, therefore, be a r e su l t of a m u l t i p l i c i t y of factors which may include food, changes i n the environmental condi t ions , and var ia t ions i n the genetic characters i nvo lv ing the physiology and behaviour of the f i s h . F i sh l i v i n g i n d i f ferent parts of 68 the r i v e r w i l l feed on dif ferent items, and depending on the type and quantity of food a v a i l a b l e , random var ia t ions i n the growth rates 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 migrat ion, Bajkov (op c i t ) , the var ia t ions 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 ferent l o c a l i t i e s where food supply and other eco log ica l factors may be s u f f i c i e n t l y di f ferent to cause marked differences i n t he i r growth ra tes . Analys is of growth i n length, both from empir ica l and back ca lcu la ted lengths, revealed no s ign i f i c an t differences i n the growth of the sexes up to age twenty. Af ter t h i s age, ca lcula ted lengths showed that the females grew fas ter . The data on empir ica l lengths i n older f i s h were not su f f i c i en t to demonstrate any differences. These data on the Fraser River white sturgeon indica te that i t s growth i n length i s i n agreement wi th some other species of sturgeon that have been studied. Probost and Cooper (1954), working wi th empi r ica l length, showed s imi l a r var ia t ions 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 he 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 ten; and 37.0 to 56.0" at age f i f t een . The small 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 69 one) . Sunde (1961) found the growth r a t e of the males and females i n the l ake s turgeon (Ac ipenser fu lvescens ) of the Nelson R i v e r very s i m i l a r up t o age twenty , but at o l d e r ages the females grew much f a s t e r . Clas sen (1944) c i t e d i n Probost 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 s t u r i o and C u e r r i e r (1949) found £he same i n Ac ipenser fu lvescens i n Northern Quebec. Probost and Cooper (1954) , however, found no ev ident d i f f e r e n c e s i n the growth of males and females of Lakes Puygan, Winneconne and Bute de M o r t e . The curves of growth obta ined by the two methods employed i n s t u d y i n g growth of the Fra ser R i v e r w h i t e sturgeon are not ve ry d i f f e r e n t i n the male up t o age t w e n t y - f i v e . A f t e r age t w e n t y - f i v e e m p i r i c a l lengths appear t o be g rea te r than the c a l c u l a t e d l e n g t h s . In females the curve determined from e m p i r i c a l l engths 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 of l engths around t h i s p o i n t . At ages h i g h e r than twenty years c a l c u l a t e d lengths 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 . In both cases these d i f f e r e n c e s c o u l d be due t o the scanty data at these o l d ages, but cou ld 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 f o r the slow growing f i s h among the females and the f a s t growing f i s h among the males . ( i . The d i f f e r e n c e i n the weights of the sexes at o l d e r ages has been a s c r i b e d t o the d i f f e r e n c e s i n the enlargement of the gonads at sexua l m a t u r i t y . No data were c o l l e c t e d t o s u b s t a n t i a t e t h i s argument but one female ( twelve fee t long and 825 pounds) caught from the Fra ser R i v e r , had o v a r i e s e s t imated 70 at 200 pounds i n weight, which indicates that the ovaries can grow to an immense s i z e . Compared wi th the other species of sturgeons that have been s tudied, 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 different species as fo l lows: Species Male Female Author i ty A. fulvescens Rafinesque 14 years 23 years Cuerr ier (1949) A . s tu r io Linne 7 - 9 8 - 1 4 Chalikov (1949) A . guldenstadt Brandt 8 - 1 4 1 3 - 2 0 Lukin (1949) A . bakr i Brandt 10 - 12 1 2 - 1 4 Kozhin (1949) A . ruthens Linne 3 - 7 5 - 1 2 Lukin (1949) Huso huso( Linne) 12 - 14 16 - 18 Chalikov (1949) Phyca (1956) mentioned that ava i lab le evidence on the Columbia River white sturgeon suggested that the females did not probably mature before eleven to twelve years. Age at maturi ty, i n the Columbia River female white sturgeon appears to be rather low. However, Sunde (1961) has shown that w i th in the same species sexual maturity i s reached at d i f ferent ages i n di f ferent regions. Spawning i n the Fraser River white sturgeon occurs at in te rva l s of f ive to ten or more years. Whether there i s any difference between the reproductive cycle i n the sexes i s not c l e a r l y indicated by the ava i lab le data. Cuerr ier (1949) c i ted i n Harkness and Dymond (1961), stated that the male sturgeon of the St . Lawrence River spawned twice as often as the female — the male spawning every two to three years and the female every three to f ive years. Late spawning maturi ty , and extended in t e rva l s between spawning, pose an important problem i n the management of sturgeon s tocks . Sturgeons must grow to a large s ize before they s tar t to spawn, and where they share waters wi th some other commercially exploi ted species i t i s inev i tab le that a subs tant ia l number of sturgeons i s caught before the f i s h reach spawning stage. In any year c lass t h i s great ly 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 natura l mor ta l i ty and catch. There i s no doubt that these factors coupled wi th intensive f i s h i n g , have played an important part i n the catastrophic decl ine i n a l l the sturgeon stocks that have been exp lo i t ed . Y i e l d curves under d i f ferent combinations of f i s h i n g and natura l mor ta l i ty have been presented showing levels of f i sh ing mor ta l i ty at which maximum y ie lds are obtained. These curves revea l that highest y i e l d i n absolute value are obtained i n conditions of only a low natura l mor t a l i t y . Under these condit ions a r e l a t i v e l y low f i sh ing mor ta l i ty rate 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 mor ta l i ty rate depletes the old age groups and the f ishery 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 sh ing mor ta l i ty rate 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 grea t ly affects the s ize of the spawning stock, and leads to deplet ion of stocks. 72 Curve B i n F i g . 21, where natural mor ta l i ty 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 mor ta l i ty rate of 0.065 which i s 50% lower than the present ra te . At the present f i sh ing mor ta l i ty 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 sh ing mor ta l i ty rate of 0.065 t h i s age would be shi f ted up to about s ixteen years. From these findings i t can be concluded that the present f i s h i n g mor ta l i ty rate i n the Fraser River white sturgeon i s too high and the f ishery 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 af ter year depends on the nature of recruitment to the f i she ry . 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 f u l l recruitment takes place at age eleven and any recru i ted year c lass remains i n the f ishery for a period of sixteen years after age eleven, the females would just have reached sexual maturity at the end of thei r i l i f e expectancy (twenty-seven years of age under the present conditions of na tura 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 natura l and f i sh ing mor t a l i t y . By the time they reach sexual maturity the females would therefore have been great ly 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 ize of the spawning stock. Sunde (1961) analysed the strength of the di f ferent year classes i n Nelson River lake sturgeon and found that low number of r ec ru i t s resul ted from years of intensive f i sh ing which suggested that recruitment was d i r e c t l y re la ted to the s ize of spawning stock. It i s obvious therefore that wi th t h i s intensive f i s h i n g on the Fraser R ive r , there has been a progressive lowering of the age at recruitment which w i l l u l t imate ly r e su l t i n complete destruction of the s tocks. 74 . MANAGEMENT . For a r a t i o n a l exp lo i t a t i on of a f i she ry , i t i s necessary that the loss from the f i shery through natural and f i s h i n g mor ta l i ty be counter-balanced by the addi t ion to i t through growth and recruitment. The present study on the Fraser River white sturgeon has revealed that the present f i sh ing mor ta l i ty rate i s too high and that most of the f i s h are being caught before they have spawned. 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 deplet ion of stocks through progressive reduction of the spawners. The deplet ion of the stocks i n the Fraser River white sturgeon has i n fact already been observed. Rodd (1926) c i t ed 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 shery . This decline however, was i n part due to the removal of the accumulated natura l stocks as has been observed i n other stocks where a - i f i shery 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 ly taken and that the species was i n danger of (commercial) •extermination. The deplet ion of sturgeon stocks through ove r - f i sh ing , however, i s not pecul iar to the Fraser River s tocks, but has been reported from many other areas i n North America, Europe, and A s i a . Evermann and Latimer (1910) stated that when commercial f i s h i n g started in the Lake of the Woods i n 1884, the lake was the greatest sturgeon pond i n the world . In the las 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 fo l lowing 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 decline i n the sturgeon population prompted i t s protect ion i n th 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 ove r - f i sh ing . Van Oosten (1937, 1939) r e f e r r ing 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 in the 1939 paper pointed out that the disappearance of th i s species was due to sheer wanton des t ruc t ion . Phyca (1956) reported that heavy commercial f i s h i n g led to the deplet ion 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 rate of exp lo i t a t i on i n the Manitoba sturgeon after 1900 resul ted i n the deplet ion of the stocks which prompted the closure of the f i shery i n 1910. Sunde reports that i n the Nelson River where exp lo i t a t ion 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 deplet ion of the stocks. This resul ted i n the closure of the f i shery i n 1929. In a l l the areas where the deplet ion has been detected measures have been taken to protect the stocks. These ^ measures 76 have taken various forms i n different areas and i n some places a combination of more than one conservation technique has been employed. These have included: 1. P roh ib i t i on of destruct ive f i s h i n g methods. 2. L icens ing . (Whereby only a l imi ted number of persons could be permitted to f i s h for sturgeon.) 3. Size l i m i t . Various s izes 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 izes the f i s h would have spawned. However, evidence from various sources has proven that most of these s ize 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 lo s ing the f ishery for 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 ishery for a long period of time to al low the stocks to bu i ld up. Several f i she 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 closure i n Lake N i p i s s i n g , Ontar io , and i n Manitoba showed no evidence of improvement of sturgeon stocks. In Michigan where the f i shery was closed for twenty-one years , there was no apparent effect on the production. Evidence from the l i f e h i s to ry of the sturgeon indicates that a prolonged closure of the f i she r ies would cause only a temporary r e v i v a l of the stocks that have been depleted. I t i s evident therefore, that these regulat ions have 77 not been r i g i d enough to protect the sturgeon stocks. 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 rapid enough to keep pace with the annual catch. On the Fraser River a 36" s i ze l i m i t has existed for a long time, and the catch i n the g i l l nets has been great ly regulated by the closed f i sh ing seasons pertinent to the salmon f i she ry . The s e t - l i n e f i shery has a l so been prohibi ted as far back as 1928, although i t i s apparent that th i s r u l i n g has not been s t r i c t l y adhered to . Though catch s t a t i s t i c s show that the production has been maintained for a rather long period of time, i t has f luctuated at a very low l e v e l . The age composition of the catch reveals that the f ishery has reached a stage where the s ize of the spawners has been so great ly reduced that future recruitment i s l i k e l y to be affected. Normally an instantaneous f i s h i n g mor ta l i ty of 0.130 would not be considered excessive but since the sturgeon i s a long- l ived f i s h , the f i s h i n g mor ta l i ty exerted over the long exploi ted phase of the f i s h ' s l i f e bui lds up to some subs tan t ia l value. Ricker (1963) has demonstrated the marked or even catastrophic effects which resu 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 teen 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 eventually 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 maturi ty , the sturgeon needs conservation measures which would protect not only the young f i s h but a lso the spawning stocks. The i nc iden t a l nature of the sturgeon f ishery on the Fraser River makes regulat ions based on s ize l i m i t rather d i f f i c u l t for the mesh s ize i s governed by the salmon f i she ry . However, the fact that the f i shery has been maintained, even at th i s low l e v e l , for a long time suggests that there has been a ce r t a in 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 tocks, i t i s thus evident that s t r i c t protec t ion should be afforded to the f i s h that escape the g i l l net f i she ry . To accomplish th i s i t w i l l be necessary to completely p roh ib i t the s e t - l i n e f i she ry . Observations on the reproductive biology of the sturgeon have indicated that egg production increases as the f i s h grow older . 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 la rger . This study has shown that under the p r e v a i l i n g mor ta l i ty rates most of the f i s h disappear from the f i shery at age twenty-seven. At th i s age the ear ly female spawners would have spawned only once and the amount of spawn would not be large. Assuming that the s u r v i v a l ra te among the eggs and the young f i s h remains the same, pro tec t ion of the spawners should be able not only to maintain 79 the stocks but a l so 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 f i sh ing mor ta l i ty rate 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. This would c a l l for a reduction i n the f i s h i n g . Th i s , however, i s not d i r e c t l y possible on the Fraser River where the f i s h i n g effor t i s directed on other species of f i s h . An ind i rec t way of doing i t would be to change the s ize l i m i t at which the f i s h are taken and step i t up to 48" fork length . At t h i s length the f i s h would on the average have reached twenty years of age. The females would not have at tained sexual maturity at t h i s age, but most of them would have spawned at least once before the end of the exp lo i t a t i on phase. This measure would involve only a change i n the mesh s ize i f the sturgeon were the only commercially important species on the Fraser River . On the Fraser R ive r , many other species, for example, sockeye, are exploi ted and these require a much smaller mesh s ize than would be needed of a sturgeon that has at tained a length of 48" i n fork length. I t i s therefore impossible i n pract ice to avoid catching . sturgeon before they a t t a in 48". Though regulat ions requ i r ing fishermen to return to the water a l l f i s h under a set length can be introduced, the fact that a lo 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 length. If 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 water i t would depr ive them of an income from the s a l e of s turgeon , which probably compensates f o r the damage done t o the n e t s . I t i s suggested t h a t the present 36" s i z e l i m i t be mainta ined as the minimum l e n g t h a t - w h i c h s turgeons may be t a k e n , and a 48" (=54* t o t a l l eng th ) s i z e l i m i t be e s t a b l i s h e d beyond which no s turgeon may be t a k e n . Th i s should o f f e r p r o t e c t i o n to 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 sturgeon beyond 48" w i l l be caught , and t h e i r r e t u r n t o the water should not cause much r e p e r c u s s i o n among the f i s h e r m e n . Breeding p laces f o r the Fra ser R i v e r whi te s turgeon were not i n v e s t i g a t e d d u r i n g t h i s s tudy . However, o ther workers have i n d i c a t e d tha t the sturgeon 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 . I t would t h e r e f o r e appear tha t on the F r a s e r , spawning p laces might occur anywhere beyond Langley t o Y a l e . I t i s i n t h i s area t o o , where the 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 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 aken . I t i s t h e r e f o r e suggested t h a t sturgeon f i s h i n g i n t h i s area be comple te ly a b o l i s h e d . In t h i s area only those l i c e n s e d commercial f i shermen o p e r a t i n g a gear i n which i t i s i n e v i t a b l e t o c a t c h s turgeon may r e t a i n f i s h that conform to the 36" t o 54" l i m i t . No data were c o l l e c t e d on the s turgeon spor t f i s h e r y on the F r a s e r R i v e r . H c wever , i t i s known tha t a l a rge number of spor t f i shermen are 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 s turgeon p o p u l a t i o n would have t o be cons idered i n any management scheme. 81 SUMMARY The growth of the Fraser River white sturgeon was studied from data co l lec ted from the fishermen's catch i n the lower part of the Fraser River , 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 cross-sections of the f i r s t pectora l f i n rays . A prel iminary study was made to determine the region of the pectoral f i n ray from which a consistent number of r ings 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 farther than %", there was a l i k e l i h o o d of underestimating age due to loss of annu l i , and i f taken too near the base of the f i n ray, sections were d i f f i c u l t to 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 ca l cu l a t i ng growth at the di f ferent ages from the cross sect ion of the f i r s t pectoral f i n ray. For the back ca l cu l a t i on method i t was necessary f i r s t to f ind the r e l a t i onsh ip between growth i n length of the f i s h and the growth of the f i r s t pectoral f i n ray. This re la t ionsh ip was found to be l inea 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 ings to the 82 periphery of the cross sec t ion , and by the equation y = -3.1 + 10.2x i f the measurements were taken along a s t ra igh t l i ne from the centre to the same point on the periphery of the cross sec t ion . Both these l ines had the same co r r e l a t i on co -e f f i c i en 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 deviat ion from a regression 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 calculated length) . After th i s age, the females grew faster than the males. However, neither sex seemed to grow to a f ixed maximum s i z e . Analysis of growth of the different year classes revealed differences i n the growth ra tes . Some year classes had a slower growth ra te . Differences i n the growth rate of d i f ferent year classes were a lso 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 re la ted 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 th in the r i v e r because di f ferent areas i n the r i v e r apparently present d i f ferent opportunit ies for growth. Due to scanty data, analyses of growth i n the d i f ferent calendar years did not reveal de f in i t e trends. Growth i n weight was studied by two methods. One was by averaging the weight of the di f ferent 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 characterized by very low increments i n weight up to age s i x to seven, but 83 inc rea sed u n i f o r m l y up to age f i f t e e n . A f t e r age f i f t e e n the data were scanty and no comparison c o u l d be made. The second method was by c a l c u l a t i n g weights at d i f f e r e n t lengths u s i n g a l e n g t h / weight r e l a t i o n s h i p . The length/weight r e l a t i o n s h i p was obta ined by p l o t t i n g the logar i thms of weight aga ins t the logar i thms 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 l i n e s t o the da ta . The equat ions obta ined were: Log W = -8 .73 + 3.13 Log L f o r males Log eW = -8 .79 + 3.15 L o g e L f o r females These equat ions were used t o c a l c u l a t e the weights at v a r i o u s l e n g t h s . Both sexes showed s i m i l a r growth up t o 3 0 " , but at lengths g r e a t e r than t h i s the females were h e a v i e r . The age at s exua l m a t u r i t y was s tud ied from the examinat ion of the f i n ray s e c t i o n s f o r per iods of r e t a rded growth. I t was found that some males become s e x u a l l y mature at age e leven but females do not mature u n t i l they a t t a i n age t w e n t y - f i v e to twenty-seven y e a r s . A l l f i s h i n both sexes do not reach sexua l m a t u r i t y at the same t i m e . There are b i g i n t e r v a l s between spawningswhich may extend from f i v e t o ten years or even l o n g e r . 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 leven to twenty-seven was found t o be 0.197 as determined from the c a t c h c u r v e . However, i t was assumed that i n u n f i s h e d c o n d i t i o n the sturgeon could l i v e t o age f i f t y and from t h i s assumption an instantaneous n a t u r a l r a t e of 0.089 and an ins tantaneous f i s h i n g m o r t a l i t y r a t e of 0.130 were c a l c u l a t e d . 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 mor ta l i ty rate i s excessive and as a r e su l t the f ishery 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 ua t ion could lead to the deplet ion of the sturgeon stocks through a reduction of the spawning stocks. Due to the inc iden ta l nature of the white sturgeon f ishery on the Fraser R ive 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 ng with the other more important f i she 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 protec t ing the spawning stocks. It i s therefore suggested that the present 36" minimum s ize l i m i t be maintained and that a 54" maximum s ize l i m i t be introduced so that no sturgeons larger or i i smaller than th i s range be taken. It i s a lso suggested that the s e t - l i n e f i shery be completely abolished and that f i sh ing for sturgeon be prohibi ted i n the area between Langley and Ya le , t h i s being the most l i k e l y region i n the lower Fraser River where sturgeons spawn. 8 5 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 R i v e r w h i t e s turgeon. Ore. 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 whi te s turgeon (Ac ipenser transmontanus) on the Columbia R i v e r . Ore . F i s h . Comm. Res. B r i e f s 3 ( 2 ) : 8-21. B r i t i s h Columbia Catch S t a t i s t i c s 1950 - 1962 - - Department of F i s h e r i e s of Canada, P a c i f i c A r e a , Vancouver, BC. C a r l a n d e r , K. D. (1947) Some trends i n the commercial f i s h e r i e on the Lake of the Woods, Minneso ta . Trans . Amer. F i s h . Soc. 77: 13-25. Chadwick, H a r o l d K. (1959) C a l i f o r n i a s turgeon t a g g i n g s tud ie s C a l i f . F i s h and Game. 45: 297-301. Chugunov, N . (1925) On the methods of age d e t e r m i n a t i o n i n the s turgeon. (From ASOV S c i e n t i f i c I n d u s t r i a l E x p e d i t i o n ) B u l l , of F i s h e r i e s Economy 11:33 (not seen) . C l a s s e n , T. E . A . (1944) E s t u d i o B i o - E s t a d i s t i c o d e l E s t u r i o n 0 S o l l o d e l G u a d e l g u i v i r (Ac ipenser s t u r i o L i n n e ) . I n s t i t u t o Espanol de Oceanographia 19:52-70 (not seen Clemens, W. A . and G. V. W i l b y (1947) F i shes of the P a c i f i c Coast of Canada. F i s h . Res . Bd. Canada B u l l . 68, Ottawa.368 pp. Commission of Conserva t ion Canada (1911) Lands, M i n e r a l s , F i s h e r i e s and Game. The Mort imer Company. L t d . 519 pp. C u e r r i e r , J . P . (1949) L ' e s tu rgeon de l a c - age - c r o i s s a n c e -m a t u r i t e . Chasse et Peche 1 (6 ) : 26. . (1951) The use of p e c t o r a l f i n rays f o r de te rmin ing age of s turgeon and other spec ies of f i s h . Can. F i s h . C u l t . 11: 17-29. D'Ancona, U . (1923) Data per l a determinazione d e l l e ta a per l o s t u d i o d e l l ' a c c r e s c i m e n t s n e g l i s t o r i o n . A t t i Reale A c c d . Naz iona le d e i L i n c e i , S e r i e Quinta 22 (3 ) : 132-137 (not seen) . D e r h a v i n , A . N . (1922) {The s t e l l a t e s turgeon (Ac ipenser s t e l l a t u s P a l l a s ) , a b i o l o g i c a l ske tch} . B i u l l . B a k i n s k o i I k h t i o l o g i c h e s k o i s t a n t a s i i 1:1-393 (not s een) . 86 Evermann, B. W. and H. W. Latimer (1910) The fishes of the Lake of the Woods and connecting waters. Proc. U. S. Nat. Mus. 39:121.136. Goode, G. B. et a l . (1884) The f i s h e r i e s and fishery industry of tKe United States. Section 1. The natural history of useful aquatic animals. U. S. Comm. Fish and F i s h e r i e s . Govern. P r i n t . O f f i c e , Washington, i-xxxiv + 895 pp. Harkness, W. J . K. (1923) The rate of growth and food of the lake sturgeon (Acipenser rubicundus). Univ. Toronto Studies. Publ. Ont. Fish. Res. Lab. 18: 18-42. - and J. R. Dymond (1961). The lake sturgeon. The history of i t s fishery and problems of conservation. Ont. Dept. of Lands and Forests, Ontario. 121 pp. Holzmayer, H. (1924) Zur Alterestimmung der Acipenscriden. Zool. Anzeiger 59:16-18. (not s e e n ) Kuzmin, A. N. (1954) The s t r u c t u r a l and developmental changes i n the testes and ovaries of juvenile sturgeon (Acipenser guldenstadt Brandt)* ( i n Russian) Doklady Akademii Nauk SSSR. New series 99(4): 645 -647. Larkin, P. A., J. G. Terpenning and R. R. Parker (1957). Size as a determinant of growth rate i n rainbow trout (Salmo g a i r d n e r i ) . Trans. Amer. Fish . Soc. 86:84-9 6"7 Lord, J . K. (1866) The n a t u r a l i s t i n Vancouver Island and B r i t i s h Columbia. Richard Bentley, London 1. 358 pp. Phyca, R. L. (1956) Progress report on white sturgeon studies. C a l i f . F i s h and Game 42(1):23-35. Prince,•E. E. (1899) The food of sturgeon. Special report appended to the 31st Ann. Rept. Dept. Mar. for 1898. Ottawa, (not seen). Probost, R., and E. L. Cooper (1954). Age, growth and . reproduction of the lake sturgeon (Acipenser fulvescens) i n the Lake Winnebago region, Wisconsin'. Trans. Amer. Fish . Soc. 84:207-227. Ricker, W. E. (1945) A method of estimating minimum size l i m i t for obtaining maximum y i e l d . Copeia 1945(2): 84 - 94. (1947) Mortality rates i n some l i t t l e exploited populations of Freshwater f i s h e s . Trans. Amer. Fish. Soc. 77:114-128. 87 Ricker , W. E. (1958) Handbook of computations for b i o l o g i c a l s t a t i s t i c s of f i s h populations. F i s h . Res. Bd. Canada, B u l l . 119, Queen's P r i n t e r , Ottawa, 300 pp. (1963) B ig effects from small causes: two examples from f i s h population dynamics. J . F i s h . Res. Bd. Canada 20(2): 257-264. Roussow, George (1957) Some considerations concerning sturgeon spawning p e r i o d i c i t y . J . F i sh 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 Le t te 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 River i n Manitoba. Unpubl. M. Sc. Thesis. Univers i ty 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 unparal le led extermination of a species. Pop. S c i . Mo. 73:361-371. Van Oosten, J . (1936) The Great Lakes F i she 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? Amer. W i l d l . May - June 1939: 130-135. APPENDIX I ANALYSIS OF STOMACH CONTENTS Date SN Length F i s h Chironomids Crayfish Molluscs Other Inv Other Items 1.5.62 178 32.5" Eu lachons 182 37.0 Eulachons 8.5.62 150 48.5 Eulachons 160 33.0 Eulachons 161 32.0 Eulachons 162 35.0 Eulachons 163 33.5 Eulachons 170 32.5 Eulachons 175 35.0 Eulachons 15.5.62 155 40.0 Eulachons a few remains 165 51.0 Eulachons 169 34.0 Eulachons 29.5.62 89 41.0 Eulachons ( f u l l stomach) 90 31.5 Eulachons 5.6.62 91 47.0 remains a few a few she l l s 92 36.0 remains a few 93 50.0 skeleton 94 32.5 Eulachons (% lb) 14.6.62 102 55.0 a sculpin a few remains 108 33.0 remains 109 34.0 a few remains spruce cone; Date SN Length Fish Chironomids Crayf ish Molluscs Other Inv Other Items 19.6.62 26.6.62 110 33.0' 3.7.62 4.7.62 111 112 44.0 37.5 113 38.0 114 31.0 116 29.0 117 24.0 118 21.5 119 19.0 120 20.5 121 15.0 122 16.0 123 11.0 124 13.0 125 51.5 126 41.5 127 36.0 128 34.5 129 36.0 130 45.5 4 sculpins (125 gm) remains (30 gm) skeleton a few a few 1 s t ickleback a few a few 1 gram skeleton 4 young sturgeons remains (28 gm) 1 sculpin (20 gm) a few remains a few remains a few remains 1 s tonef ly larva a few remains 14 gm green vegetable matter Sand. 4 pieces wood 2 Odonata larvae Green veg. matter Wood 2 Stonefly Detr i tus larvae a few Ephemeroptera larvae cadd i s f ly cocoons 4 s tonefly larvae Detr i tus 2 s tonefly larvae Detr i tus Pieces of wood Sand Pieces of wood Sand co so Date S N Length F i sh Chironomids Crayf ish Molluscs Other Inv Other Items 10.7.62 17.7.62 18.7.62 24.7.62 25.7.62 134 135 137 138 182 183 184 185 186 188 33.5" 32.5 136 32.0 34.0 36.5 139 62.0 140 51.0 142 34.0 143 31.5 144 32.0 145 38.0 37.0 45.5 45.5 37.0 27.0 189 36.0 190 34.5 a few remains a few remains rather p l e n t i f u l a few 6 gm remains a few remains 1 sculpin 4 gm 6 gm 6 gm a few remains 34 gm 1 gm she l l s Pieces of wood Vegetable matter Pieces of wood Pieces of wood vo o Date SN Length F i s h Chironomids Crayfish Molluscs Other Inv Other items 2.8.62 192 193 194 199 200 12.0" 15.5 29.0 a few 195 25.0 196 15.0 197 22.0 198 18.5 22.5 19.5 201 18.5 202 15.5 203 14.0 204 9.5 205 9.0 206 8.5 207 9.5 208 209 18.5 Largest s ingle group Remains 40% of contents a few 2 a few 25% of a l l contents A few remains p l e n t i f u l 2 gm a few a few s h e l l s Mysids 1 s tonefly larva Mysids 20 1 s tonefly la rva 1 Mysid A few Copepods 2 Mysids few she l l s a few she l l s Pieces of wood Detr i tus p l e n t i f u l Detr i tus p l e n t i f u l De t r i tus , •vegetable matter, f i s h eggs, pieces of wood Detr i tus p l e n t i f u l Detr i tus Wood, f i s h eggs, Detr i tus Detr i tus Small amount of veg matter Vegetable matter: biggest group  Date SN Length F i sh Chironotnids Crayfish Molluscs Other Inv Other Items 2.8.62 211 212 14.5 14.0 16.8.62 213 15.0 215 12.0 216 12.0 217 13.0 218 13.0 227 36.0 228 33.0 222 34.0 223 34.5 224 33.5 225 34.0 226 37.0 227 36.0 228 33.0 a few remains a few remains a few 10 20 30 a few 1 sculpin a few a few 1 s t ickleback 10 a few Wood, eggs 1 sculpin 30 a few a few a few remains a few remains Mysids 5 A. few Mysids Eggs, sand, pieces of wood Mysids 30 Chaoborus 5 Cyclops a few Mysids 60?o Detr i tus p l e n t i f u l Stonefly l a rva 1 Stonefly larva 1 Stonefly larva 1 Stonefly larva 1 Stonefly larva 1 Pieces of wood Pieces of wood, green veg matter Green vegetable matter Detr i tus roots Pieces of wood Pebbles Date SN Length F i sh Chironomids Crayfish Molluscs Other Iny Other Items 21.8.62 229 42.0" 1 sculpin 230 41.0 231 31.0 p l e n t i f u l a few Chaoborus Sand 25.8.62 232 32.0 larvae 4.10.62 246 34.0 a few Pieces of wood 248 33.0 1 lamprey 5.10.62 251 33.5 20 Sand, pieces of wood 94 APPENDIX I I In the work sheets presented i n Appendix I I , column 1 r e f e r s t o the age of 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 ages. Column 3 g ives the weight of f i s h at d i f f e r e n t ages as computed from the l e n g t h / weight r e l a t i o n s h i p . Column 4 r epresent s the ins tantaneous r a t e of growth and i s obta ined by t a k i n g the d i f f e r e n c e of the n a t u r a l logar i thms of two adjacent y e a r s . Columns 5 and 6 represent the instantaneous r a t e s 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 . Column 7 i s the r e s u l t a n t growth. I t r epre sent s the d i f f e r e n c e between growth and the components of m o r t a l i t y , g - (p+q). The weight f a c t o r i n column 8 i s ob ta ined 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 the corre sponding age i n column 7. Column 9 g ives the weight of the s t o c k . In a l l these computations i t i s assumed tha t 1000 weight u n i t s are r e c r u i t e d t o the f i s h a b l e s tock a year i n advance of the f i s h i n g . The weight of the s tock i n the f i r s t f i s h a b l e year i s t h e r e f o r e obta ined by m u l t i p l y i n g 1000 by the weight change f a c t o r i n that y e a r , and f o r the subsequent years by m u l t i p l y i n g the weight change f a c t o r by the weight of the s tock i n the preced ing y e a r . The average weight of the s tock i n column 10 i s the mean weight of the s t o c k i n two adjacent y e a r s . Column 11 g ives the y i e l d from a s tock i n a f i s h i n g p e r i o d and i s obta ined by m u l t i p l y i n g the average weight of the s tock by the instantaneous r a t e of f i s h i n g m o r t a l i t y . The t o t a l f o r column 11 g ives 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 f i s h e r y . Age AvL AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 - 2.46 7 24.1 3,36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.6 34 70.6 101.0 35 71.7 106.0 £-(v+a) w t- -Change Wt. of Ay. Wt. , Y i e l d s K y 4 ; Factor Stock of Stock 1000 .44 .05 .025 .365 1.448 1448 .33 .05 .025 .255 1.297 1878 1679 .31 .05 .025 .235 1.278 2387 2133 .20 -.05 .025 .125 1.939 2719 2553 .33 .05 .025 .255 1.297 3527 3123 .24 .05 .025 .165 1.185- 4179 3853 .33 .05 .025 .255 1.297 5420 4800 .10 .05 .025 .025 1.031 5588 5504 .17 .05 .025 .095 1.105 6175 5882 .17 .05 .025 .095 1.105 6823 6499 .14 .05 .025 .065 1.073 7321 7072 .16 .05 .025 .085 1.094 8009 7665 .14 .05 .025 .065 1.073 8594 8302 .11 .05 .025 .035 1.041 8946 8770 .10 .05 .025 .025 1.031 9223 9085 .13 .05 .025 .055 1.062 9795 9509 .10 .05 .025 .025 1.031 10099 9947 .10 .05 .025 .025 1.031 10412 10255 .10 .05 .025 .025 1.031 10735 10514 .09 .05 .025 .015 1.020 10950 10843 .09 .05 .025 .015 1.020 11169 11080 .11 .05 .025 .035 1.041 11627 11398 .07 .05 .025 -.005 0.990 11511 11569 .08 .05 .025 + .005 1.010 11626 11569 .06 .05 .025 -.015 0.980 11393 11510 .06 .05 .025 -.015 0.980 11165 11279 .06 .05 .025 -.015 0.980 10942 11054 .06 .05 .025 -.015 0.980 10723 10833 .06 .05 .025 -.015 0.980 10508 10616 .05 .05 .025 -.025 0.970 10193 10351 .05 .05 .025 -.025 0.970 9887 10040 .05 .05 .025 -.025 0.970 9590 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 U l Age AvL AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.74 6 21.7 2.46 7 24.1 3.36 8 26.1 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 g e (p+qi Wt. Change Wt. of Av. Wt. s Factor Stock of Stock Y i e l d .44 .05 .04 .35 1.419 .33 .05 .04 .24 1.271 .31 .05 .04 .22 1.246 .20 .05 .04 .11 1.116 .33 .05 .04 .24 1.271 .24 .05 .04 .15 1.162 .33 .05 .04 .24 1.271 .10 .05 .04 .01 1.010 .17 .05 .04 .08 1.083 .17 .05 .04 .08 1.083 .14 .05 .04 .05 1.051 .16 .05 .04 .07 1.073 .14 .05 .04 .05 1.051 .11 .05 .04 .02 1.020 .10 .05 .04 .01 1.010 .13 .05 .04 .04 1.041 .10 .05 .04 .01 1.010 .10 .05 .04 .01 1.010 .10 .05 .04 .01 1.010 .09 .05 .04 - 0 1.000 .09 .05 .04 0 1.000 .11 .05 .04 .02 1.020 .07 .05 .04 -.02 0.980 .08 .05 .04 -.01 0.990 .06 .05 .04 -.03 0.970 .06 .05 .04 -.03 0.970 .06 .05 .04 -.03 0.970 .06 .05 .04 -.03 0.970 .06 .05 .04 -.03 0.970 .05 .05 .04 -.04 0.961 .05 .05 .04 -.04 0.961 .05 .05 .04 -.04 0.961 1000 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 ovoo <r voro r>-ONrv<f rv r-l <f CM ro •r4 rv ON r-i ro vo ON HCMsf m rv co ON ON >* r-l r-l r-4 r-l CM <M CM CM CM CM CM CM • CJ id ° w • ' > 4-1 < o M-l Or* o • o 4-1 -U 13 CO CJ p r C u u o •w • o 4 J i CD + a v> I 60 c r 00 r-J oo o o O i n o o m i o o o i o i o o o " N O i n o i n m i o u N O i n o o i o o u N O i n o o u 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 - n N obn vf O n V. r—l i—I CM CM CO CO <j" CM rv o ON o r-l r-l r-l r-l O r w t vo rv CM ON <T VO vO m m m CM VD m ON <r rv <f VO 00 oo ON o o o O ON ON 00 rv m m m m m m vO VD vO vo m m m m m r-l CM r-l ON ON r-l r-i r-l o o vO 00 r-l vO vO m m m m ON CO CM m bo 00 oo o o o o ON ON m m m m m VO vO vO vO mm r-l O o o o o CO O o O ON ON 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 CO CM CM i—I CM i—l CM 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 m m 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 o o 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 <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 OOnMfOOJn 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 <r o o m ON m vj-r» vo vo o o m l - ^ f O v o N ^ ^ d ' n r ^ ^ ^ ^ ^ ^ r ^ N v o o N N l - l O r - l o o ^ ^ ^ « J ' c ^ l o ^ t » N o ^ c O r ^ ^ o o o 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 - I H H r-INNNncOfO^^i/iinvDvONNrvCOONONOO r-l r-l o o O H N Q i n N H O O V D C f t O O O 0 0 0 \ 0 0 i n O O ^ N C h v O N O < O O N i n N O N ^ N ON CM vtKoNr^vtvoooocomr^ONOcMv^voooOr-icn^voooor-icnvjm Or-tcMcov^mvorv . oooNO^cMcnv^mvoiv*cooNOi-tcMcovjm i-ICM<nvjmvOrvOOCT»r-4r-lr-<i-lr-4r-lr-lr-lr-lr-ICMCMCMCMC^ 98 csovooo>t foococNi\oc \ i<rvovo^o«cro^ i-N. m cr»Or-*coc^vocM< f c^r^cooococ»r> . v D r-irHcMvoc« CM .—i vO 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 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: .-IHIHT - 4CMCN«CMCMCMCMC^COCOCOCOCOCOCMCMC^ C M vO m CM m VO o m o> vDCM T-l O CO CO CM VO o VO t—11—t CM CM CO CO 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 v O C O O H O r J r ^ O O O N O O O O M D O O ' - I O M O f O H O ' o o o H c o v o i n > c f i n c o c N i c n o c \ i c v j v o v o i n v D > * c o c M c M < f s f r ^ c r \ o n r J H o o o o ( > i n o ^ r H i o o o i n i o o i o o o o O ' - i r s > i n i n i n k D o o o 3 o \ i - i ( r )^^^o^ooNooc^ l n^(^^^r^ o ^ ^ ^ ^ o o c^oooovo< f CVIOMVD^NOON r ^ H c M C M c M c o < t < r < t < f ^ < f i n i n i n i n i n i n i n^ . < r < t ^ H v O r - l s f y 3 0 N V O O C N | N r - l r - ( 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 O v < t C M C T > < r r O s f ^ v O v O c O i n c n O C T k C M O N O > C ^ n N N o i N ^ N ^ o o o o o o o ^ o ^ o i ^ O N O N O ^ c ^ O N a c ^ ^ O N O ^ c ^ o * 1 H f - l ^ - l ^ - l r - l ^ - ( > — I O ' - i < - H > — i T - t H r - l O ' — ( O O O O O r - I O O O O O O O o o o n N O ^ N ( n N r ^ v O v O n u ^ n O ^ N r ^ r ^ r 4 ' N N O ^ n i A i n i T i l O i n v O » O v O CO CMCM O CM r-t CM O O O O O O O O O O O O O O O O O O Q O O O O I I I I I I I I I I I I I I I 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 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 i n i n i n i n i n i n i n i n i n i n > n i n i n i n i n i n i n i n i n i n i n i n i n i n u o i n i n i n 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 o o o ^fO»-IO(*)<f r n O N O i ^ ^ O ^ i - I O P l O O O f f i ^ i - l N O O v O v O ^ O v O v O i A i n i O <3" COCO CM tONnrlHHHrlHHHHrlr lHOOHOOOOOOOO o o <f o o m cy>in <r <i- vo vo o o m r ^ c o ^ o c ^ l ^ ^ J ^ H ^ c ^ ^ l ^ H N ^ o N N H O r ^ c o ^ ^ s f ^ ^ o ^ t o o ( ^ l o ^ c O ' - ^ ^ - l O o r - i > - 4 c M c o < j " i n r ^ O t - i f O i n o o I-H <j- r^o<fr-.r-(voom«-iinomON<i-oiOT-i\o i—11—11—11—11—< CMCM CNicococo<t<l"ininvovor>>.f^r^coo\ONOO O l ^ N O l n ^ r ^ ^ ^ f n ^ o c ^ o o o M C ^ o o l A O O v p c J C ^ v D ^ l O l n o N l ^ l ^ o N ^ o ^ . ONcM^r ON«-< <r voco o c o inNc^oN'<tvoc)OOr-ipN<f\oooO'-(cnvd-invoooo\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 AvW g q P g-(p+q) Wt. Change Factor Wt. of Stock Av. Wt. of Stock Y i e l d 1 9.0 .154 2 12.1 .390 1000 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 .44 .05 .075 .315 1.377 1377 6 21.7 2.46 .33 .05 .075 .205 1.234 1699 1538 115.350 7 24.1 3.36 .31 .05 .075 .185 1.209 2054 1877 140.775 8 26.0 4.10 .20 .05 .075 .075 1.083 2224 2139 160.425 9 28.3 5.70 .33 .05 .075 .205 1.234 2744 2484 186.300 10 30.6 7.25 .24 .05 .075 .115 1.128 3095 2920 219.000 11 33.9 10.1 .33 .05 .075 .205 1.234 3819 3457 259.275 12 35.0 11.1 . 10 .05 .075 -.025 .970 3704 3762 282.150 13 37.0 13.2 .17 .05 .075 + .045 1.051 3893 3799 284.925 14 39.0 15.6 .17 .05 .075 + .045 1.051 4092 3993 299.475 15 40.8 18.0 .14 .05 .075 + .015 1.020 4174 4133 309.975 16 42.9 21.2 .16 .05 .075 + .035 1.041 4345 4260 319.500 17 44.8 24.2 .14 .05 .075 + .015 1.020 4432 4389 329.175 18 46.5 27.1 .11 .05 .075 -.015 .980 4343 4388 329:100 19 48.0 30.0 .10 .05 .075 -.025 .970 4213 4278 320.850 20 50.0 34.1 .13 .05 .075 + .005 1.010 4255 4234 317.550 21 51.6 37.8 .10 .05 .075 -.025 .970 4127 4192 314.400 22 53.2 41.7 .10 .05 .075 -.025 .970 4003 4065 304.875 23 54.9 46.1 .10 .05 .075 -.025 .970 3883 3943 295.725 24 56.6 50.4 .09 .05 .075 -.035 .961 3732 3808 285.600 25 58.2 55.2 .09 .05 .075 -.035 .961 3586 3659 274.425 26 60.0 61.0 .11 .05 .075 -.015 .980 3514 3550 266.250 27 61.5 65.4 .07 .05 .075 -.055 .942 3310 3412 255.900 28 63.0 70.8 .08 .05 .075 -.045 .951 3148 3229 242.175 29 64.2 75.2 .06 .05 .075 -.065 .932 2934 3041 228.075 30 65.5 79.9 .06 .05 .075 -.065 .932 2734 2834 212.550 31 66.7 84.8 .06 .05 .075 -.065 .932 2548 2641 198.075 32 68.0 90.1 .06 .05 .075 -.065 .932 2375 2462 184.650 33 69.2 95.6 .06 .05 .075 -.065 .932 2214 2295 172.125 34 70.6 101.0 .05 .05 .075 -.075 .923 2044 2129 159.675 35 71.7 106.0 .05 .05 .075 -.075 .923 1887 1966 147.450 .05 .05 .075 -.075 .923 1742 1814 136.050 -• - ••• 7551.825 LOO r-i •rl v o v o t 7 \ v O H m n o o o r - i O r - i i n ^ i n H 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 c N i n c N i ^ v o i r j o o r ^ r ^ i n c o v o o < r c N c > . ^ o < r 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 oo O C M <r i-v o r- l ON ON CO oo rv in CO CM r-< ONf-- NO m co r- l r - l O r-i CM CM CM CM 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 ro vt o <t ro rv m • o 4J O is 4 J to > IW CM CM CO CM rv. m v t NO CO rv. O rv. m CM in r» CM rv. m m m <r NO rv oo CO NO ON rv r-l O r l CO ON ON CO r-l o 00 CM NO ON 00 <r CM r-l ON rv NO m NO rv. CO ON r-l <t CO CM rv. CO <frvo rv. oo o CO <t CO CM CM r-l O ON 00 rv NO v t co CM r-i o ON CO rv. NO NO m vT v t CO CO r-l r-l r-t r-l CM CM CM CM CM CM CM CM r-l r-l r-l r-l r-l r-l r-l r-l r-l 0 X :0 O ;o v t r- l CM 00 m m CO r- l CM CM CM rv. CM r v o CO ON m r - l ON r v co CO m i—i NO 00 m co CM o O CM CM CO r o m oo CM CM r-l r- l o ON rv. NO ro CM r-l O ON co rv. NO m CM CM CO CM CM r-l r-l r-l r - l r-l r- l r- l r- l r - l 00 C o •U: CO o o r-l O r-l CM ON ON NO oo NO ro ON ON ON ON ON ON + P. v > I 60 N O i n c o c s i m N o m c O r - i r - i s t < M s f i v o o i n o o o o o o o \ O N r s H OCMCMCMCMCMCOCOCO C M r - l r - I Q r - I O r - I O O O O O O O O O O O O O O O r - l r - l r - l r - l r - l r ^ r H l T - l r - l r - l I I I I I I I I I I I r o r o r o c o c M r o r o c o c o i v » c ^ c o c o c o c o c o c o c o c o c o c o c ^ a* • inin^ininininininininininininininininininininininininini^ OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 60 '.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 ; < f O C O N C O C N ! O O H r ^ 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 v t o o m ON m <f rv NO vo o o m r - I C ^ ^ C M r v . v t C O r - l r v . C M r - l r - t C M v O O C M C M r - 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 . H C N i c N i c N i n n t n ^ ^ t n i n v o v o i v N N O o o N O N O O i < o o om oo O H N O < f N ^ O ^ ^ O \ O O O W O N O O l O O O v O N f f i « 3 N O i r i O N i r i N O N v O N ONN>JNC^r^sJvooOOn ION ^ ON>d"vflOOO>Hro<f vOOO O'-'fOKf mvOoOONOr-l r - i r - i r ^ r - i c M c M c M c M c o c o c o c o c o ^ r v t v t v t v t i n u o i n i n i n i n N O v ^ 0) 60 < , 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 AvW g q P g-(p+q) Wt. Change Factor Wt. of Stock Av. Wt. of Stock Y i e l d 1 9.0 .156 2 12.1 .390 1000 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 .44 .05 .25 - .14 1.150 1150 6 21.7 2.46 .33 .05 .25 + .03 - 1.030 1185 1168 292.00 7 24.1 3.36 .31 .05 .25 + .01 1.010 1197 1191 297.75 8 26.0 4.10 .20 .05 .25 + .10 .905 1083 1140 285.00 9 28.3 5.70 .33 .05 .25 + .03 .970 1051 1067 266.75 10 30.6 7.25 .24 .05 .25 -.06 .942 990 1021 255.25 11 33.9 10.1 .33 .05 .25 + .03 .970 960 975 243.75 12 35.0 11.1 .10 .05 .25 - .20 .819 786 873 218.25 13 32.0 13.2 .17 .05 .25 -.13 .878 690 738 184.50 14 39.0 15.6 .17 .05 .25 -.13 .878 606 648 162.00 15 40.8 18.0 .14 .05 .25 -.16 .852 516 561 140.25 16 42.9 21.2 .16 .05 .25 - .14 .869 448 482 120.50 17 44.8 24.2 .14 .05 .25 - .16 .852 382 415 103.75 18 46.5 27.1 .11 .05 .25 -.19 .827 316 349 87.25 19 48.0 30.0 .10 .05 .25 - .20 .819 259 288 72.00 20 50.0 34,1 .13 .05 .25 -.17 .844 219 239 59.75 21 51.6 37.8 .10 .05 .25 - .20 .819 179 199 49.75 22 53.2 41.7 .10 .05 .25 - .20 .819 147 163 40.75 23 54.9 46.1 .10 .05 .25 - .20 .819 120 134 33.50 24 56.6 50.4 .09 .05 .25 -.21 .810 97 109 27.25 25 58.2 55.2 .09 .05 .25 - .21 .811 79 88 22.00 26 60.0 61.0 .11 .05 .25 - .19 .827 65 72 18.00 27 61.5 65.4 .07 .05 .25 -.23 .795 52 59 14.75 28 63.0 70.8 .08 .05 .25 - .22 .803 42 * 47 11.75 29 64.2 75.2 .06 .05 .25 - .24 .787 33 38 9.50 30 65.5 79.9 .06 .05 .25 - .24 .787 26 30 7.50 31 66.7 84.8 .06 .05 .25 - .24 .787 20 23 5.75 32 68.0 90.1 .06 .05 .25 - .24 .787 16 18 4.50 33 69.2 95.6 .06 .05 .25 - .24 .787 13 15 3.75 34 70.6 101.0 .05 .05 .25 -.25 .779 10 12 3.00 35 71.7 106.0 .05 .05 .25 -.25 .779 8 9 2.25 .05 .05 .25 -.25 .779 6 7 1.75 3044.50 102 o i o o o m i r i y i o u - i i r i o i n o i o i n i n o i o i n 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 ^ o o r s C N i c r v o o o x c n i n v o 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 o N O O r ^ r ^ N c s i c s i N N C N i N N c x i N N H H o o c y i C f i o o f l o r v i N i n r ^ i ^ r ( r ( ^ r ( r ( r l r - l r < H r ) r ( r H r l r ( 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 CONtO i r i O > ^ ^ 0 * O ^ ^ J *0«3 0 H O r - i r - * 0 0 0 > C O O O N i f i r i r - i O \ N i n r H O rHrHCMCMrorOv^vJstvjv^ixiu^inmininm O C f t ^ ^ r ^ o o o O O N i r i O N i - l i n O O i n i r i O i n O O O O N M v O i r i i r i y D O O O O l J i r - l o 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-l r^i-lCMCMCMCOvtvtvTvt<rvJir)inLninin r l v O r l 4 v O ( 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) ovDrvinininiriinst<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 vtvtvtvtvt<rvtvtvt<rvtvtvt 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 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 i t i i i i i g i i i g i 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 0 0 0 * 0 0 0 0 0 * 0 0 0 0 0 * 0 0 0 0 0 0 0 * 0 0 cnc^<^ONC^ONC3Nc>c>^aNavo\(^c^ 0 0 0 0 « D O O C O O O O O O O C O C O C O O O C O C O C O C O C O O O O O C O C O ( X ) O O O O C O T O 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-IOOr-^OOC O O O O O O O <f o o LO CJN iT> vt rv vD vO O O lO r ^ n v O N r v ^ C O r ^ N C N l r ^ H N v O O N N ^ O ^ O O N W ^ N O s f WN^OOr^r-lOO 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 * * O O O O * r - iHr - i i - i r^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 « * 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-iri r- ir-i(NCMcMCMrorororocnvtvtvtvt<rinmminin r-icMrovtmvorvoocy»i-^r-ir-ir-4r-ir-irHr-ii—ir-icsl<NCMcMcMcMcMCMcMCMcococorococo 103 vocMocNj<fvocN4ovo<rCNi<r<t o oo o O H N « t OOAOOvO Ot^vD^r^ON|vNCOCOOO>*ON01vOO>iNvOO,4'CA(n ^ r v co r - i CM <t <r <f ^  ^  ^  ^  uo <t <t stf c o c ^ v O r o <tOOlOCnT-*<tCOO<fvOC^r-lr -IOOtf^ incoocorv.csiinuovorvoocrvcorv . rv .vouovtcocMr^ r - ir-icMcMcvrrococococococococococococococococ^ O O O r - l C O < r C N l ^ O \ C V . V O C N O r v . < t * - ^ O r ^ r - l .00 VO v f v t NO CO !\ o v £ > Q \ c o O r - i u o v T C T > c o r v . c ^ c o o o c o c o c M r ^ c o v o o N r - i v o c ^ u o v f i r t r v . r v . c o c y k i n r ^ r ^ r - l r - I C M C N C M C O C O C O C O C O C O C O C O C O C O C O O O C O C O C O O ^ CM CM CM r—I r—I r—I 1—I ' c ^ H ^ ( n r H O r l O r ^ r - ^ O r - ( o o o o O O O ' - ^ r - l O N r ^ N N N N N ( , ^ ( 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^^^ t 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 + + + + + I + I I I I I I I I 1 I I I I O O O O O O O O O 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^ O O C O O O C O C O C O O O C O O O C O C O C O C O O O C O C O C O C O C ^ 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 ! 4fOt-i Or^<r(^0^^<r* < ^ l-^0c^ o o o o^t^ r^^co^o^o^ovo^ 0 l 0 l n l n i 4 n n N M N C n r - < r - l r - l t - l ^ r - < r - l r - l r - l r H r - l r - I O O ' - I O O O O O O O O O O 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 o t n o c N i i o r s O N v o N CT>CMNtfrv,C^'-l<tvOCOOCOiOrv.C3NOcMvtvOOOOr^ ,-4r-lr-lr-ICMCMCMCMCOCOrOOOCOvtvtvtv+<fl^ O r H c M n s t ^ v o r ^ o o o N O ^ N n s t i n o r ^ o o c T i O ' - i c N i r n s r i o 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 ( r l 104 •H r * CJ 4J O CO < o 4-1 OX : CJ O 4 J £ CO OO e CO 6 4 J cr + a I 60 60 > < 0) 60 <c i n i n o i o o m i f l O O i n i n i n i n o o o o i f i o o o i n i n o ^ o o i ' i ^ ' O i o u^r-(rv<frv.ir^vOCT\CTv<*r-4cac\l^ CM v^(^^COOrHCMi-(sO<J>r-(C^O<fOvOO<fOOrH rv , oooNr - i co«AvovDvovorvrvrvvovDmmvtcocoCMi - i r - i ooNOOoorwovoin OA rv oo ro r- l C O vt ON vt r-l CO 00 00 ON r o rv m o o vo CO O A 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 O O C M vt vt r o vt rv 00 rv ON ON rv. rv r o C M O VO O •n r o CO moo vt r- l 00 co 00 00 in m m C M ON VO O r o vo ON Ovt rv C O r-l C M c o c o vt vt CO C M r-l O r-l 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 r-l r - l r - l mooOvoooovororoocMorvvooNvovovommrvcovtcMcM CM CM CM I-I I-I I-I cocMr-locMr-^cMONoooooaNo^aNONO ^ c ^ a N O N a N O N O N O N O N O N O N O N O N O N O N r - l r - l r - l r - l r - < r - l r - I O r - < r H 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 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 I I I I f i l l I m m m m m i n m m m m m m i n m m m m m m m m m m m m m m m m m 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 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-iocovtcoorvrvvtvOvtr-ioroooooNONr-irvco vovovovovo in mm vtrOrOCMCOCSlrOi-lr-lrHr-lr-lr-lr-lr-lr-lr-lr-lr-IOOr-IOOOOOOOOOO vt o o m o N r n v t r v v o v o o o i n r-l c o vo CM rv vti r o r-l rv CM r—t r - < 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 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 rorocovtvtvtvtvtinmmmminvDvovovovovovovorvrv I-I CM c o vt jn 'O rv oo ON I-I O r-icMrovtmvorvooc ^ O r-icMOvtmvot^ o o o ^ O r-icMrovtm r-|r-lr-4r-<r-4i-li-lr^i-lr-ICMCMCMCMCMCMCMCMCMCMCOrOr^ g ,q p g-(P+q) W t ' C t i a t l g e W t - f AY. Wt. Y i e l d s M I 6 Factor Stock of Stock  1000 1336 1599 1468 88.08 1877 1738 104.28 1973 1925 115.50 2362 2168 130.08 2584 2473 148.38 3093 2839 170.34 2941 3017 181.02 3000 2971 178.26 3060 3030 181.80 3029 3045 182.70 3059 3044 182.64 3028 3044 182.64 2910 2969 178.14 2767 2838 170.28 2712 2740 164.40 2579 2646 158.76 2453 2516 150.96 2333 2393 143.58 2198 2266 135.96 2071 2135 128.10 1990 2031 121.86 1836 1913 114.78 1711 1774 106.44 1564 1638 98.28 1429 1497 89.82 1306 1368 82.08 1194 1250 75.00 1091 1143 68.58 987 1039 62.34 893 940 56.40 808 851 51.06 Age AvL - - AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.1 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 .44 .089 .06 .291 1.336 .33 .089 .06 .181 1.197 .31 .089 .06 .161 1.174 .20 .089 .06 .051 1.051 .33 .089 .06 .181 1.197 .24 .089 .06 .091 1.094 .33 .089 .06 .181 1.197 .10 .089 .06 .049 0.951 .17 .089 .06 .021 1.020 .17 .089 .06 .021 1.020 .14 .089 .06 — .009 0.990 .16 .089 .06 - +.011 1.010 .14 .089 .06 .009 0.990 .11 .089 .06 _ .039 0.961 .10 .089 .06 .049 0.951 .13 .089 .06 .019 0.980 .10 .089 .06 .049 0.951 .10 .089 .06 _ .049 0.951 .10 .089 .06 — .049 0.951 .09 .089 .06 _ .059 0.942 .09 .089 .06 — .059 0.942 .11 .089 .06 _ .039 0.961 .07 .089 .06 — .079 0.923 .08 .089 .06 _ .069 0.932 .06 .089 .06 — .089 0.914 .06 .089 .06 .089 0.914 .06 .089 .06 _ .089 0.914 .06 .089 .06 _ .089 0.914 .06 .089 .06 — .089 0.914 .05 .089 .06 _ .099 0.905 .05 .089 .06 .099 0.905 .05 .089 .06 — .099 0.905 4002.54 b U l Factor Stock of Stock 1 9.0 .154 2 12.1 .390 3 14.2 .656 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 .44 .089 .075 .276 1.323 .33 .089 .075 .166 1.185 .31 .089 .075 .146 1.162 .20 .089 .075 .036 1.041 .33 .089 .075 .166 1.185 .24 .089 .075 .076 1.083 .33 .089 .075 .166 1.183 .10 .089 .075 .064 0.932 .17 .089 .075 + .006 1.010 .17 .089 .075 + .006 1.010 .14 .089 .075 _ .024 0.980 ,16 .089 .075 _ .004 1.000 .14 .089 .075 _ .024 0.980 .11 .089 .075 .054 0.591 .10 .089 .075 _ .064 0.942 .13 .089 .075 _ .034 0.970 .10 .089 .075 .064 0.942 .10 .089 .075 _ .064 0.942 .10 .089 .075 _ .064 0.942 .09 .089 .075 _ .074 0.932 .09 .089 .075 _ .074 0.932 .11 .089 .075 _ .054 0.951 .07 .089 .075 _ .094 0.914 .08 .089 .075 _ .084 0.923 .06 .089 .075 _ .104 0.905 .06 .089 .075 _ .104 0.905 .06 .089 .075 _ .104 0.904 .06 .089 .075 _ .104 0.905 .06 .089 .075 .104 0.905 .05 .089 .075 _ .114 0.896 .05 .089 .075 .114 0.896 .05 .089 .075 .114 0.896 1000 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 . 0 0 0 166.425 156.750 147.600 138.300 128.925 121.350 113.175 103.950 95.025 86.025 77.850 70.425 63.750 5 7 . 3 7 5 51.450 46.125 4 2 1 2 . 7 5 Age A VL AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 56.9 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 g-(p+q) Wt. Change Wt. of Av. Wt, Factor Stock Stock Y i e l d .44 .089 .13 + .221 1.246 .33 .089 .13 .111 1.116 .31 .089 .13 .091 1.094 .20 .089 .13 -.019 0.980 .13 .089 .13 .111 1.116 .26 .089 .13 .021 1.020 .33 .089 .13 .111 1.116 .10 .089 .13 -.119 0.887 .17 .089 .13 -.049 0.951 .17 .089 .13 -.049 0.951 .14 .089 .13 -.079 0.923 .16 .089 .13 -.059 0.942 .14 .089 .13 -.079 0.923 .11 .089 .13 -.109 0.896 .10 .089 .13 -.119 0.887 .13 .089 .13 -.089 0.914 .10 .089 .13 -.119 0.887 .10 .089 .13 -.119 0.887 .10 .089 .13 -.119 0.887 .09 .089 .13 -.129 0.878 .09 .089 .13 -.129 0.878 .11 .089 .13 -.109 0.896 .07 .089 .13 -.149 0.861 .08 .089 .13 -.139 0.869 .06 .089 .13 -.159 0.852 .06 .089 .13 -.159 0.852 .06 .089 .13 -.159 0.852 .06 .089 .13 -.159 0.852 .06 .089 .13 -.159 0.852 .05 .089 .13 -.169 0.844 .05 .089 .13 -.169 0.844 .05 .089 .13 -.169 0.844 1000 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 v j 108 <u >"• O 4J O 5: 4J w > UH <. o CJ o U co 0) 60 C CO • O V CO + I 60 60 5 0> 60 < o o o o o o m o o o m o i h o m m i o o o o C i i n i n o i n o i o o i n o i n o m o m m m r v . i r i i n i n o J i n N i n N i N r N O O O ^ N c s i o N i n N i n N O r v m ON o o ON rv t o CM coiovtvornrv.invoc^cMcx)vtrHcovoiOvtoocMr-irH 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 - l r H i - l o o LO r> vt CM 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 r-l o ON ON 00 CC rv lOlO<t ro CM CM rH rH rH r H r H o lOvt rH CM CO vO CO o O ON VO CM rH CM r-t o rH O OONON CO CO rH rH r-i rH v t r v v t O r H m o vO CO CM CM r H U0 ON lO rv. rH CO rH ON CO rH 00 00 rv. r v 00 rHONCT>ONO\o>ONcr»cj»ONONCTvcjNONaNONONo^ o o N r n o ONOcn V O V O O N N 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 H O O H O O O N H H r ^ H H N N N N N N N N N N N N N N C S N N N N I t i l l I I t I I I I I I I I u o i o i o i o i o i o u o i n i o i o u o i o i o u o t n i n i o i o t n i o i n u ^ CMCMCMCMCMCMCMcMCMCMCMCMCMCMcMCMCMcMCMCMCMCMCMCMC^ QAONC>ONCT»C^ONO\ON^O\C*E^ C X J O O C O O O C O C O C O O O C O C O O O C O C O C O C O C O C O O O O O C O C O O O C O C 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 v t v t 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 rlH r l O O r l O O O O O O O O O O v t O O lO ON iO v t t v v o vO O O"0 r H C n v O O J h . s l - C O r - l Hr-I O J O O ^ N N OHCOrVrH^N 0<fCONC^COrHr - l O O rH rH CM CO v t i n r v OrH OO'OCOrH^trv.Ovtrv.rHvDO'OrHlOOlOONvtfOtOrHVO rHH r H r H r H N N N c n n r O s f ^ i n i o v D v o r v r v r v o o o N C j N O O O O C M O m r v r H O O O v O O N O O O C O ^ C O u o O O v O C M O N v O C M O i O O C M i O r - v O C M v O r v 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 v O C O O r ^ r O v j v O v O C O C N O r l 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 Age AyL AvW g „ ./,0+a.\ ^....Change Wt. of Ay. , W t . . Y i e l d _ 8 ^ P l q ; Factor Stock of Stock Y i e i q 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 .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 .44 .10 .025 .315 1.377 .33 .10 .025 .205 1.234 .31 .10 .025 .185 1.209 .20 .10 .025 .075 1.083 .33 .10 .025 .205 1.234 .24 .10 .025 .115 1.128 .33 .10 .025 .205 1.234 .10 .10 .025 .025 0.970 .17 .10 .025 .045 1.051 .17 .10 .025 .045 1.051 .14 .10 .025 .015 1.020 .16 .10 .025 .035 1.041 .14 .10 .025 .015 1.020 .11 .10 .025 _ .015 0.980 .10 .10 .025 .025 0.970 .13 .10 .025 .005 1.010 .10 .10 .025 _ .025 0.970 .10 .10 .025 _ .025 0.970 .10 .10 .025 _ .025 0.970 .09 .10 .025 _ .035 0.961 .09 .10 .025 _ .035 0.961 .11 .10 .025 .015 0.980 .07 .10 .025 _ .055 0.942 .08 .10 .025 .045 0.951 .06 .10 .025 mm .065 0.932 .06 .10 .025 .065 0.932 .06 .10 .025 .065 0.932 .06 .10 .025 _ .065 0.932 .06 .10 .025 -.065 0.932 .05 .10 .025 .075 0.923 .05 .10 .025 .075 0.923 .05 .10 .025 — .075 0.923 1000 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 AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.9 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 g g-(p+q) Wt. Change Factor Wt. of Stock Av. Wt,. of Stock Y i e l d .44 .10 .04 .300 1.350 .33 .10 .04 .190 1.209 .31 .10 .04 .170 1.185 .20 .10 .04 .060 1.062 .33 .10 .04 .190 1.209 .24 .10 .04 .100 1.105 .33 .10 .09 .190 1.209 .10 .10 .04 mm .040 0.961 .17 .10 .04 .030 1.031 .17 .10 .04 .030 1.031 .14 .10 .04 0 1.000 .16 .10 .04 .020 1.020 .14 .10 .04 0 1.000 .11 .10 .04 _ .030 .970 .10 .10 .04 _ .040 .961 .13 .10 .04 _ .010 .990 .10 .10 .04 mm .040 .961 .10 .10 .04 .040 .961 .10 .10 .04 _ .040 .961 .09 .10 .04 mm .050 .951 .09 .10 .04 mm .050 .951 .11 .10 .04 mm .030 .970 .07 .10 .04 mm .070 .932 .08 .10 .04 _ .060 .942 .06 .10 .04 .080 .923 .06 .10 .04 _ .080 .923 .06 .10 .04 mm .080 .923 .06 .10 .04 mm .080 .923 .06 .10 .04 mm .080 .923 .05 .10 .04 mm .090 .914 .05 .10 .04 mm .090 .914 .05 .10 .04 mm .090 .914 1000 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 AvW g q p 1 • 9 .0 12.1 .154 2 .390 3 14.2 .650 4 17.0 1.24 .44 5 19.5 1.77 .10 .05 .290 6 21.7 2.46 .33 .10 .05 .180 7 24.1 3.36 .31 .10 .05 .160 8 26.0 4.10 .20 .10 .05 .050 9 28.3 5.70 .33 . 10 .05 .180 10 30.6 7.25 .24 .10 .05 .090 11 33.9 10.1 .33 .10 .05 .180 12 35.0 11.1 .10 .10 .05 .050 13 37.0 13.2 .17 .10 .05 .020 14 39.0 15.6 .17 .10 .05 .020 15 40.8 18.0 .14 .10 .05 - .050 16 42 .9 21.2 .16 .10 .05 .010 17 44.8 24.2 .14 .10 .05 — .010 18 46 .5 27.1 .11 .10 .05 — .040 19 48 .0 30.0 .10 .10 .05 - .050 20 50.0 34 .1 .13 .10 .05 - .020 21 51.6 37.8 .10 .10 .05 — .050 22 53.2 41.7 .10 .10 .05 — .050 23 54 .9 46 .1 .10 .10 .05 - .050 24 56.6 50.6 .09 .10 .05 — .060 25 58 .2 55 .2 .09 .10 .05 - .060 26 60.0 61.0 .11 .10 .05 - .040 27 61.5 65.4 .07 .10 .05 - .080 28 63.0 70.8 .08 .10 .05 — .070 29 64.2 75.2 .06 .10 .05 — .090 30 65.5 79.9 .06 .10 .05 - .090 31 66.7 84.8 .06 .10 .05 — -090 32 68 .0 90.1 .06 .10 .05 - .090 33 69,2 95.1 .06 .10 .05 - .090 34 70.6 101.0 .05 .10 .05 - . 100 35 71.7 106.0 .05 .10 .05 — .100 .05 .10 .05 .100 1000 1.336 1336 1.199 1599 1468 73.40 1.174 1877 1738 86*90 1.051 1973 1925 96*25 1.197 2362 2168 108.40 1.094 2584 2473 123.65 1.197 3093 2839 141.95 0.951 2941 3017 150.85 1.020 3000 2971 148.55 1.020 3060 3030 15:1.5.0 0.990 3029 3045 152.25 1.010 3059 3044 152.20 0.990 3028 3044 152.20 0.961 2910 2969 148.45 0.951 2767 2839 141.95 0.980 2712 2740 137.00 0.951 2579 2646 132.30 0.951 2453 2516 125.80 0.951 2333 2393 119.65 0.942 2198 2266 113.30 0.942 2071 2135 196.75 0.961 1990 2031 101.55 0.923 1837 1914 95.70 0.932 1712 1775 88.75 0.914 1565 1639 81.95 0.914 1430 1498 74.90 0.914 1307 1360 68.45 0.914 1195 1251 62.55 0.914 1092 1144 57.20 0.905 988 1040 52.00 0.905 894 941 47.05 0.905 809 852 42.60 3336.00 Wt. of Stock Age AvL AvW 1 9.0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 56.5 79.9 31 66.7 84.0 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 g g-(p+q) Wt. Change Factor Av. Wt. of Stock Y i e l d .44 .10 .06 .280 1.323 .33 .10 .06 .170 1.185 .31 .10 .06 .150 1.162 .20 .10 .06 .040 1.041 .33 .10 .06 .170 1.185 .24 .10 .06C .080 1.083 .33 .10 .06 .170 1.185 .10 .10 .06 -.060 .942 .17 .10 .06 .010 1.010 .17 .10 .06 .010 1.010 .14 .10 .06 -.020 .980 .16 .10 .06 0 1.000 .14 .10 .06 -.020 .980 .11 .10 .06 -.050 .951 .10 .10 .06 -.060 .942 .13 .10 .06 -.030 .970 .10 .10 .06 -.060 .942 .10 .10 .06 -.060 .942 .10 .10 .06 -.060 .942 .09 .10 .06 -.070 .932 .09 .10 .06 -.070 .932 .11 .10 .06 -.050 .951 .07 .10 .06 -.090 .914 .08 .10 .06 -.080 .923 .06 .10 .06 -.100 .905 .06 .10 .06 -.100 .905 .06 .10 .06 -.100 .905 .06 .10 .06 -.100 .905 .06 .10 .06 -.100 .905 .05 .10 .06 -.100 .896 .05 .10 .06 -.110 .896 .05 .10 .06 -.110 .896 1000 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 t o 113 i -4 • r - l > CJ > o to > < 4 H < o O s t m i o i r n r i i o i o i n o o o o i n i n i n i n o o ^ ^ ^ o i f l i n o i n o M f l i o o r v . i v » t ^ c N i r ^ r ^ r ^ r v O i n o O r v C N J C M CN ON OcMco<rvocooNcocorv.rvvDinvjcn<oc^ ro ro in ro ON r - ro O N r - , ro rv v O CM CM CM CM r v l-l m r-l CO 0 0 l-l i n r v CM m O N v t O N CM r-l in in CM o ON oo r- l ON O N r v in ON CM m CO r v in ro O r v m v t v t v t v t <r v t v D CO CM VO o m <r v O r v ON CM <r m <f CO ro CM rH ON 0 0 fv V D <f CO CM rH O ON 0 0 r v v D m in v T •cl-cn rH r-l r-l I-I CM CM CM CM CM CM CM CM CM r-l r-i r-l r-l rH r-l r-l r-l l-l H - l o o S cn o O 0 0 ON v t r H r v r v ON vO ON <r r v r v r v r v v t in r v ON r v in v t ONin v t v t v t ro r H r H 0 0 CM o r H ro vD CM v t ON ON OO v t 00 v t ON o m ON O VD ro r H ON 0 0 oca v t ON O CM in ON CO r v CO o ro in r v 0 0 r H CM vo v t vo v t ro CM CM o CO CO vo in v t CM r H r H ON 0 0 P v r v . VD in v t v t CO ro l-l r H r H r H r H CM CM CM CM CM CM CM CM CM C M r H r H r H r H r H r H r H r H cu 00 c CO JC U u 5 4J O 4 J CO 5 rt. O v t O r H v t CO v t ro o o -4 O r H CM CO r H CO COCO v t v t CM vo in r v r v r v r v r v CO 0 0 oo r H r v in CO 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 co oo CO CO r v r v r v CO r H r H o r H 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 oo co co cr + a v-» I 00 inininininininininintntnininininininini^  V O i n n N ^ V D i n N O O n r ^ ( ^ V O r v v J N r v N O O M v O O C T \ r H ^ r - t r - l r - I N N N 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 I I I I I I I I I I I | I I I I I I I I • m i n i n i n i n i n i n i n i n i n i n i n i n i n i n i n i n i n i n i n 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 HHHHHHHHHHHHi-IHHHHHi-IHHHHr-IHHHr-IHH HH 00 • d , ( O H O n 4 n O N N < t v O < f r - I O ( n O O O C n 0 N H N 0 0 v 0 « \ O \ 0 v 0 i n i n i O 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 vt o o inoNinvtrvvDvooom 1 - l t O v O C M r ^ v t C O r H r v . C M r H r H C M v O O C N C M r - I O i - I M 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 < O H N O i O N H O n v O a i O O O O O ^ O O i n O O v O N O N v O N O i O O N i O N O C v l v O S ON CM vtrv.a>f-Hvtvoc»ocoinfv.a>ocNvtvoc»OrHcovtv^ r H r H r H r H C M C M C M C M C O C O C O C O C O v t v t v t v t v t i n i n i n m CD 60 O H N r n < r i n o N c o c ^ O ' ^ N r n v t i n o r v c o c J N O r H N r O ' t i O 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 Age AvL AvW 1 9.0 .154 2 12.1 .290 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4.10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39.0 15.6 15 40.8 18.0 16 42.9 21.2 17 44.8 24.2 18 46.5 27.1 19 48.0 30.0 20 50.0 34.1 21 51.6 37.8 22 53.2 41.7 23 54.9 46.1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63.0 70.8 29 64.2 75.2 30 65,5 79.9 31 66.7 84.8 32 68.0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 8 q p g-(p+q) Wt. Change Factor Wt. of Stock Av. Wt. of Stock Yie l d 1000 .44 .10 .13 .210 1.234 1234 .33 .10 .13 .100 1.105 1365 1299 168.87 .31 .10 .13 .080 1.083 1477 1421 184.73 .20 .10 .13 -.030 0.970 1433 1455 189.15 .33 .10 .13 +.100 1.105 1583 1508 196.04 .24 .10 .13 + .010 1.010 1599 1591 206.83 .33 .10 .13 + .100 1.1052 1767 1638 212.94 .10 .10 .13 -.130 . .878 1551 1659 215.67 .17 .10 .13 -.06 .942 1461 1506 195.78 .17 .10 .13 -.06 .942 1376 1419 ' 184.47 .14 .10 .13 -.09 914 1258 1317 171.21 .16 .10 .13 -.07 .932 1172 1215 157.95 .14 .10 .13 -.09 .914 1071 1122 145.86 .11 .10 .13 -.12 .887 950 1011 131.43 .10 .10 .12 -.13 .878 834 892 115.96 .13 .10 .13 -.10 .905 755 795 103.35 .10 .10 .13 -.13 .878 663 709 92.17 .10 .10 .13 -.13 .878 582 623 80.99 .10 .10 .13 -.13 .878 511 547 71.11 .09 .10 .13 -.14 .869 444 478 62.14 .09 .10 .13 -.14 .860 386 415 53.95 .11 .10 .13 -.12 .887 342 364 47.32 .07 .10 .13 -.16 .852 291 317 41.21 .08 .10 .13 -.15 .861 251 271 35.23 .06 .10 .13 -.17 .844 212 232 30.16 .06 .10 .13 -.17 .844 179 196 25.48 .06 .10 .13 -.17 .844 151 165 21.45 .06 .10 .13 -.17 .844 127 139 18.07 .06 .10 .13 -.17 .844 107 117 15.21 .05 .10 .13 -.18 .835 89 98 12.74 .05 .10 .13 -.18 .835 74 81 10.53 .05 .10 .13 -.18 .835 62 68 8.84 3206.84 Wt. change Wt. of Ay.. Wt. . Factor Stock of Stock Age' AvL AyW 1 9 .0 .154 2 12.1 .390 3 14.2 .650 4 17.0 1.24 5 19.5 1.77 6 21.7 2.46 7 24.1 3.36 8 26.0 4 .10 9 28.3 5.70 10 30.6 7.25 11 33.9 10.1 12 35.0 11.1 13 37.0 13.2 14 39 .0 15.6 15 40 .8 18.0 16 42 .9 21.2 17 44 .8 24.2 18 46 .5 27.1 19 48 .0 30.0 20 50 .0 34.1 21 51.6 37.8 22 53 .2 41.7 23 54 .9 46 .1 24 56.6 50.4 25 58.2 55.2 26 60.0 61.0 27 61.5 65.4 28 63 .0 70.8 29 64.2 75.2 30 65.5 79.9 31 66.7 84.8 32 68 .0 90.1 33 69.2 95.1 34 70.6 101.0 35 71.7 106.0 g g-(p+q) Y i e l d .44 .10 .25 .09 1.094 .33 .10 .25 -.02 .980 .31 .10 .25 - . 04 .961 .20 .10 .25 - .15 .861 .33 .10 .25 - . 02 .980 .24 .10 .25 - .11 .896 .33 .10 .25 - .02 .980 .10 .10 .25 -.25 .779 .17 .10 .25 - . 18 ,835 .17 .10 .25 - . 1 8 .835 .14 .10 .25 - .21 .811 .16 .10 .25 - . 1 9 .827 .14 .10 .25 - .21 .811 .11 .10 .25 - .24 .787 .10 .10 .25 - .25 .779 .13 .10 .25 - . 22 .803 .10 .10 .25 - .25 .779 .10 .10 .25 - .25 .779 .10 .10 .25 - .25 .779 .09 .10 .25 - .26 .771 .09 .10 .25 - . 26 .771 .11 .10 .25 - . 2 4 .787 .07 .10 .25 - .28 .756 .08 .10 .25 - .27 .763 .06 .10 .25 - . 29 .748 .06 .10 .25 - . 2 9 .748 .06 .10 .25 - . 2 9 .748 .06 .10 .25 -.29 .748 .06 .10 .25 - . 29 .748 .05 .10 .25 - . 3 0 .741 .05 .10 .25 - . 3 0 .741 .05 .10 .25 - . 30 .741 1000 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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