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Spawning times and early life history of Hilsa ilisha in Bangladesh Hossain, Mokammel Md. 1985

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Spawning  times and  early  Hilsa ilisha in  life history  of  Bangladesh  by Md.  A  Mokammel  Hossain  t h e s i s s u b m i t t e d i n p a r t i a l fulfillment of the requirements f o r the degree Master  of  Science  in T h e F a c u l t y of G r a d u a t e S t u d i e s ( D e p a r t m e n t of Zoology)  We  a c c e p t t h i s t h e s i s as c o n f o r m i n g to t h e required standard  The University  of B r i t i s h  April ©Md.  Columbia  1985  Mokammel  Hossain  In p r e s e n t i n g  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  requirements f o r an advanced degree a t the  the  University  o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e f o r reference  and  study.  I further  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may  be granted by the head o f  department o r by h i s o r her r e p r e s e n t a t i v e s .  my  It i s  understood t h a t copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain  s h a l l not be  allowed without my  permission.  Department o f The  U n i v e r s i t y of B r i t i s h Columbia  1956  Main M a l l  Vancouver, Canada V6T  DE-6  ^^Usy  (3/81)  1Y3  written  ABSTRACT  Sexual  c o n d i t i o n of  A u g u s t 1984  from  female  Hilsa  was  sampled  f r e s h w a t e r , e s t u a r i n e and  from  October  marine localities in  1983  Bangladesh.  A t C h a n d p u r , on t h e R i v e r M e g h n a , c h a n g e s in gonadosomatic i n d e x t h a t e a r l y monsoon  ( J u n e ) , late monsoon  a r e the major s p a w n i n g p e r i o d s . to six months old (12 cm Hatching lated  otolith  spawning peaks. were  long) b y  studied  readings,  counting  and  of  juveniles areas  (<10  migrate 12 cm, the  less  samples  from  than  deeper  all disappeared  river  towards  experimental t h e u p p e r and  in d i f f e r e n t  obtained  nets,  beach  8 cm  ft depth).  to the  (February)  growth  r i n g s of o t o l i t h s .  months were back  the  up  existence  of  calcu-  the  three  M i g r a t o r y movements of j u v e n i l e H i l s a i n the R i v e r M e g h n a  from  fish  daily  confirmed  e x p e r i m e n t a l d r i f t gill n e t t i n g , and analysis  winter  showed  A g e s of j u v e n i l e H i l s a were determined  dates of j u v e n i l e s c o l l e c t e d  from  ( O c t o b e r ) , and  to  When river from  by  seines  in total  by  fishermen's  and  from  length  juveniles (>10  experimental gear.  ft d e p t h )  a  sea  was  and  by  mean  indicated length  by  catch  and  shallow  larger  size  (>7  in J a n u a r y .  the  analysis  After  cm)  direction juveniles  d o w n s t r e a m a r e a s of t h e R i v e r M e g h n a .  of  river they  reaching  T h e i r migration  of  by  indicated  shore  t h e d e e p e r r i v e r in May.  the  seining,  Length-frequency  fishermen's  inhabit  attain  beach  from  gilling  in  collected  in  TABLE OF CONTENTS ABSTRACT  ii  -  LIST OF TABLES  i v  LIST OF FIGURES  V  ACKNOWLEDGEMENTS  VH  1- INTRODUCTION  1  2. MATERIALS AND METHODS  5  2.1 2.2 2.3 2.4 2.5  Samples of a d u l t s Experimental s e i n i n g F i s h e r m e n samples of j u v e n i l e s Experimental g i l l n e t t i n g Otolith interpretation  5 8 11 16 16  3. RESULTS 3.1 3.2  3.3  23  S p a w n i n g t i m e a s i n d i c a t e d by f e m a l e s e x u a l c o n d i t i o n H a t c h i n g d a t e and e a r l y g r o w t h b a s e d on o t o l i t h s 3.2.1 O t o l i t h development 3.2.2 Age o f j u v e n i l e H i l s a 3.2.3 V a l i d a t i o n o f age d e t e r m i n a t i o n ( t e t r a c y c l i n e , s a l i n e , Peterson) 3.2.4 Hatching dates  23 26 27 27 42 43  M i g r a t o r y movements o f j u v e n i l e s 3.3.1 Length f r e q u e n c y a n a l y s i s of e x p e r i m e n t a l beach s e i n e and f i s h e r m e n s ' g e a r 3.3.2 E x p e r i m e n t a l g i l l net s a m p l i n g 3.3.3 Gil ling direction 3.3.4 J u v e n i l e s i z e s i n d i f f e r e n t r e g i o n s o f R i v e r Meghna . . .  4. DISCUSSION  48 49 53 56 56  62  4.1  Spawning  4.2  Early  4.3  Migratory  periods  growth  62  and h a t c h i n g d a t e  movements  of  juveniles  LITERATURE CITED  70 73  79  APPENDIX  »• 88  -  HI-  L I S T OF TABLES  TABLE 1.  TABLE 2.  Number of growth r i n g s counted i n o t o l i t h s of j u v e n i l e Hi 1 s a , c o l l e c t e d from the Meghna R i v e r of North Chandpur i n 1983-1984 Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent Hi 1sa i n marine h a b i t a t , c o l l e c t e d from C h i t t a g o n g i n 1983-1984  APPENDIX TABLE 1.  APPENDIX TABLE 2.  Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent H i ! s a i n e s t u a r i n e , c o l l e c t e d from B a r i s a l i n 1983-1984  41  ... 68  ... 89  Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent H i l s a i n Meghna R i v e r , c o l l e c t d from Chandpur i n 1983-1984  -iv  -  90  L I S T OF FIGURES  FIGURE  FIGURE FIGURE  FIGURE FIGURE FIGURE FIGURE FIGURE  FIGURE  1.  2. 3.  4. 5. 6. 7. 8.  9.  FIGURE 10.  FIGURE 11.  FIGURE 12.  Hi 1 sa i l i s h a i n d i f f e r e n t s i z e groups t a k e n from F i s h l a n d i n g c e n t r e , A p r i l 1 5 , 1984. The s m a l l e r are about 14 cm l o n g and about 7 months o l d . The on t h e l e f t i s about 53 cm l o n g and i s p r o b a b l y a adult Map o f B a n g l a d e s h showing t h e d i f f e r e n t stations  Barisal fish largest mature  2  sampling 6  C o l l e c t i n g samples by e x p e r i m e n t a l beach s e i n e a t Tarpachandi a r e a i n t h e R i v e r Meghna o f North Chandpur, March 6 , 1984  9  Fishermen c a t c h i n g j u v e n i l e H i l s a by boat s e i n e i n t h e Meghna R i v e r o f N o r t h Chandpur, March 6 , 1984  12  Fishermen o p e r a t i n g e n c i r c l i n g s e i n e i n t h e Meghna o f N o r t h Chandpur, A p r i l 2 5 , 1984  14  Intraperitoneal Hi l s a  River  t e t r a c y c l i n e i n n o c u l a t i o n of j u v e n i l e 18  S a l i n e / t e t r a c y c l i n e immersion e x p e r i m e n t s o f j u v e n i l e Hilsa  20  Seasonal f l u c t u a t i o n s o f Gonadosomatic Index ( w i t h s t a n d a r d e r r o r ) o f female H i l s a i n t h r e e h a b i t a t s ( R i v e r Meghna, e s t u a r i n e and m a r i n e ) .  24  O u t l i n e s o f H i l s a o t o l i t h s showing t h e i r development. R e s p e c t i v e t o t a l l e n g t h s o f f i s h were: A, 2.1 cm; B , 3 . 2 cm; C , 4 . 1 cm; D, 5 . 3 cm; E, 6 . 1 cm; F, 7.1 cm; G, 8 . 4 cm; and H, 9 . 3 cm. A l l o u t l i n e s same m a g n i f i c a t i o n ; o t o l i t h H i s 112 urn maximum l e n g t h . Otolith of F i g . 9 a: i = a n t i r o s t r u m , i i = e x c i s u r a m a j o r ; b: i=rostrum, i i = a n t i r o s t r u m ; c: i=rostrum, ii=antirostrum, i i i = p a r a r o s t r u m , i v - p o s t r o s t r u m , v = s e r r a t e d edge 28 Ground and p o l i s h e d s a g i t t a l o t o l i t h from Meghna j u v e n i l e H i l s a ( 4 . 3 cm) showing primordium ( m a g n i f i c a t i o n 410x)  River 30  C e n t r a l a r e a o f ground and p o l i s h e d s a g i t t a l o t o l i t h from Meghna R i v e r j u v e n i l e Hi 1sa ( 6 . 1 cm) showing a double primordium ( m a g n i f i c a t i o n 410x)  32  Ground and p o l i s h e d s a g i t t a l o t o l i t h from Meghna j u v e n i l e H i l s a ( 3 . 7 cm) showing t h e growth r i n g s (Bar = urn 2 . 5 ) .  35  -  v-  River  FIGURE 13.  FIGURE 14.  FIGURE 15. FIGURE 16.  FIGURE 17.  Ground and p o l i s h e d s a g i t t a l o t o l i t h of j u v e n i l e H i l s a (11.1 cm) from Meghna R i v e r showing t h e growth r i n g s (Bar y u m 2 . 5 )  37  Number of d a i l y r i n g s i n o t o l i t h s of j u v e n i l e Hi 1sa o f different sizes. C i r c l e s a r e means, v e r t i c a l l i n e s a r e ranges. Data i n T a b l e 1. L i n e f i t t e d by eye t o l e n g t h s up t o 12 cm  39  Length f r e q u e n c y d i s t r i b u t i o n of j u v e n i l e H i l s a c o l l e c t e d from t h e Meghna R i v e r of North Chandpur, 1983-1984  44  Date of f o r m a t i o n of t h e f i r s t o t o l i t h growth r i n g (horizontal axis) i n juveniles collected in different months i n d i c a t e d at l e f t  46  Frequency d i s t r i b u t i o n of j u v e n i l e H i l s a i n d i f f e r e n t depth zones i n t h e Meghna R i v e r o f North Chandpur, 1983-1984  . . . 50  FIGURE 18.  Frequency d i s t r i b u t i o n of j u v e n i l e H i l s a and a d u l t H i l s a caught by e x p e r i m e n t a l g i l l net i n t h e Meghna R i v e r o f North Chandpur, 1983-1984 54  FIGURE 19.  G i l l i n g d i r e c t i o n of j u v e n i l e Hi 1sa caught by e x p e r i m e n t a l g i l l net i n t h e Meghna R i v e r on A p r i l 7 , 1984. Boat was d r i f t i n g downstream d u r i n g sampling p e r i o d  57  FIGURE 20.  Mean t o t a l l e n g t h of j u v e n i l e H i l s a i n t h e d i f f e r e n t a r e a s . Upper areas - f i s h from t h e R i v e r Padma, c o l l e c t e d from Paksey and R a j s h a h i ; middle areas - f i s h from t h e R i v e r Meghna, c o l l e c t e d from Chandpur; lower areas - f i s h from t h e e s t u a r y , c o l l e c t e d from B a r i s a l 59  FIGURE 21.  Diagrammatic summary of seasonal t i m i n g of a d u l t m a t u r i t y ( G . S . I . = Gonadosomatic I n d e x ) , h a t c h i n g , growth and movement of young. Peak h a t c h i n g times i n d i c a t e d by t r i a n g l e s , e x t e n t o f p r i n c i p a l h a t c h i n g p e r i o d s by h o r i z o n t a l b a r s . Open c i r c l e s a r e mean l e n g t h s from e x p e r i m e n t a l s e i n i n g i n s h o r e ; s o l i d c i r c l e s a r e mean l e n g t h s from f i s h e r m e n ' s c a t c h o f f s h o r e ; v e r t i c a l l i n e s are s i z e ranges. Diagonal l i n e s suggest boundaries f o r o f f s p r i n g from d i f f e r e n t p r i n c i p a l spawning periods 66  .vi-  ACKNOWLEDGEMENTS  I Dr.  would  C.C.  like  Lindsey  for  to  express  his  patience,  appreciation support  i n d e b t e d to D r s . J ,D. MacPhail and D r . G.H.  to  and  my  supervisor,  stimulation.  G e e n , members of my  I am  also  Supervisory  Committee, f o r t h e i r h e l p f u l comments. I am Livestock and  Mr.  very  g r a t e f u l to D r .  D i v i s i o n ) , Mr. P.C.  Jeorge  A.Q.  Youssouf  Ali (Ex-secretary,  Chowdhury  (Fishery  Advisor,  Fisheries  and  ( D i r e c t o r , F i s h e r i e s Department) FAO/UNDP  in  Dhaka)  for  their  encouragement. I would Mr. my  Das  particularly  l i k e to t h a n k  Dr.  Nitya Nanda for their co-operation  G.  Melvin,  i n the  Mr.  field  Sanaullah  obtaining  data  and for  thesis. T h a n k s to M e s s r s . I n d r a B a b u , P a t a u r i , A z i z of t h e C h a n d p u r F i s h e r i e s  C a m p u s f o r t h e i r help in the l a b o r a t o r y Financial Development  support Research  to  the  Centre  G o v e r n m e n t of B a n g l a d e s h . support My Thorpe  and  author of  I am  work. was  Canada,  provided through  also g r a t e f u l to D r .  Diana  MacPhail  for their  help.  Mokammel, f o r her e n c o u r a g e m e n t and Finally, p a r e n t s , Mr. f o r c e i n my  the  project  International aids  to  the  F . B r i a n D a v y f o r his  encouragement.  t h a n k s to L i n d a D u n c a n , Moira G r e a v e n , Don and  by  I would T.  like  H o s s a i n and  to  Z.  this  thesis  H o s s a i n , who  life.  -  I also t h a n k  my  wife,  Selina  enthusiasm.  dedicate  Mrs.  H a l l , Mike B r a d f o r d , Ron  vn-  in  memory  of  my  late  were the prime motivating  1  1. INTRODUCTION Hilsa ( F i g . 1) ,  ilisha belongs  Hilsa occurs water  (Hamilton),  currently  to t h e s u b f a m i l y  known  Alosinae  as  Hilsa  o r Hilsa  of t h e Family  Clupeidae.  in f o r e s h o r e a r e a s , e s t u a r i e s , b r a c k i s h water lakes a n d f r e s h -  rivers,  i n the  western  division  of t h e  Indo-Pacific faunistic  It is held to be anadromous b y most a u t h o r i t i e s but some a u t h o r s it is not t r u l y a n a d r o m o u s (Raja 1984). and  Iraq on the P e r s i a n  sea,  G u l f , along  erroneously)  believed  from  (Pillay  to be that the  adults  s u b s i s t o n small food  been  T h e commonest  (about  life  Cochin  China  history pattern is  the  young  go t o sea  shed after  H i l s a have many long gill r a k e r s , a n d all stages  forms  25,000 s q u a r e  in Bangladesh  miles  s o u r c e of p r o t e i n . T h e  the largest delta in the world,  in a country  of 55,000 s q u a r e  miles.  p o p u l a t i o n of 90,000,000 p e r s o n s is h e a v i l y d e p e n d e n t on f i s h . f a r t h e most important  The  H i l s a is b y  s p e c i e s , c o n t r i b u t i n g p e r h a p s 33% of t h e total c a t c h  while  no o t h e r  single species contributes over  three  countries in the Upper fishery,  (perhaps  particles.  Ganges-Brahmaputra  commercial  Arabian  35.6 cm to 54.0 cm i n l e n g t h )  In B a n g l a d e s h , H i l s a is an immensely important  occupying  reported  of S r i l a n k a , a n d from  l a r g e n u m b e r s of small d e m e r s a l e g g s i n r i v e r s ; some weeks i n f r e s h w a t e r .  a r g u e that  Its marine r a n g e e x t e n d s from Iran  It h a s also  t h e c o a s t a l waters a n d R o s a 1963).  region.  the west coast of India in the  a n d i n t h e B a y of B e n g a l .  (Vietnam)  shad  B a y of B e n g a l  Bangladesh  something o v e r 100,000 t o n n e s .  is reported  5% ( L i n d s e y region,  to take  where  1981). Hilsa  the largest  Of t h e forms a s h a r e of  In India the l a n d i n g s may a c c o u n t to 25,000  t o n n e s , a n d in B u r m a about 4,000 t o 5,000 t o n n e s (Raja  1984).  2  FIGURE  1.  Hilsa ilisha  in different  l a n d i n g c e n t r e , A p r i l 15,  s i z e groups taken from B a r i s a l F i s h 1984.  The s m a l l e r f i s h are  14 cm long and about 7 months o l d .  The l a r g e s t on the  i s about 53 cm long and i s p r o b a b l y a mature  adult.  about left  3  4  The partly  present  because  because  of t h e  problems  of the  of  managing  of  knowledge  lack  scarcity  of means  of  the  Hilsa  of t h e  fishery  life  implementing  are d a u n t i n g ,  history,  any  and  control  With a view to s o l v i n g some of t h e s e p r o b l e m s , a H i l s a f i s h e r y and  the  fiscal  year  development  basis for a sound extensive  Basic  s t r u c t u r e and  biological  on  this  information  age of t h e f i s h  management p r o g r a m .  work  by  the  R e s e a r c h C e n t r e , i s p l a n n e d to be implemented i n  1985-1986.  migration, population  that  measures.  management project of t h e G o v e r n m e n t of B a n g l a d e s h , a s s i s t e d  I n t e r n a t i o n a l Development  partly  species  A has  on  is to be  spawning,  acquired  review of t h e l i t e r a t u r e been  done  in  India,  as a shows  but  in  B a n g l a d e s h t h e information is limited. The  principal  spawning  times  of  and  the  estuarine, females;  2) to  o t o l i t h s , and  by  Hilsa  in  Meghna  determine  River)  the  t i m e s , and  experimental drift  m i g r a t o r y movements of y o u n g and  different  age  were 1) to d e t e r m i n e t h e  habitats  in  as  indicated  of  young  Bangladesh  by  Hilsa  sexual by  3) to s t u d y , from samples gill  netting,  and  by  (marine,  condition  examining  t h e r e b y b a c k - c a l c u l a t e t h e i r h a t c h i n g dates as an  c h e c k of s p a w n i n g seining,  goals of t h e p r e s e n t r e s e a r c h  of  their  independent  obtained by  beach  fishermens's g e a r , t h e  H i l s a from shallow to deep p a r t s of t h e r i v e r  from t h e r e t o w a r d s t h e s e a .  5  2.  2.1  MATERIALS AND  METHODS  Samples of a d u l t s To adult  procure  H i l s a was  During  this  specimens f o r the  study  s t a r t e d in O c t o b e r 1983  period  the  commenced a g a i n i n May  monsoon 1984.  of g o n a d  and  rains  size,  sampling  c o n t i n u e d to A u g u s t  ended  in N o v e m b e r  of  1984.  1983  and  T h e sampling s t a t i o n s , s u c h as C h a n d p u r ,  B a r i s a l and  C h i t t a g o n g , are shown in F i g . 2.  B a r i s a l and  C h i t t a g o n g , r e p r e s e n t e d c a t c h e s from the M e g h n a R i v e r , t h e  estuarine Samples  and  the  were  marine  taken  monthly  m o n t h l y at C h a n d p u r . from  the  commercial  preserved  (Bay in  of  Samples from  Bengal)  habitats  Chittagong  and  Chandpur,  respectively.  Barisal,  and  twice  In each s a m p l i n g , 25 f i s h were t a k e n at random catch  in ice in a  at  landing  special  stations  insulated  box  and  and  were  immediately  t r a n s p o r t e d to  the  laboratory. In the l a b o r a t o r y , t h e total l e n g t h of each specimen on  a  standard  premaxilla  to  fish the  measuring end  of  board,  either  from  lobe  of  l o n g e r , without s t r e t c h i n g t h e f i s h i n any total  length  Bangladesh  was  chosen  region.  s e n s i t i v e to 0.01  The  gm.  w e r e r e m o v e d , and  because  of  total weight  The  specimen  t h e i r weight  the the  way.  anterior tail,  was  taken  measured  t i p of  whichever  the was  In t h e p r e s e n t s t u d y ,  i t s common was  was  use on  in  the  a Sauter  Indobalance  t h e n c u t open and the g o n a d s  noted to the n e a r e s t g r a m .  A total of  939  s p e c i m e n s from the t h r e e sampling stations were examined; of t h e s e  411  were  females.  Sex  of the  specimens  were  determined  by  visual  6  FIGURE  2.  Map of Bangladesh showing the d i f f e r e n t  sampling s t a t i o n s .  LEGEND  © ©  CHITTAGONG CHANDPUR BARISAL  © © ©  PAKSEY RAJSHAHI TARPACHANDI - — C H I R A R C H A R ( MEGHNA RIVER ) CHANDPUR NILKAMAL ( M E G H N A RIVER )  10 0 10 20 I I ' ' ' S C A L E IN MILES  89*  _|  •0°  _l  92 •  _1_  8  observation  of  gonads,  or,  in  the  case  of  immature  gonads,  by  microscopic observation. The  body  weight  and  gonad  weight  h a b i t a t s were r e c o r d e d each month.  of  female  Hilsa  in all the  Gonadosomatic i n d e x was  calculated  f r o m the f o r m u l a : „r-  G o n a d weiqht  T  = — 5 —  GSI  r -  Body 2.2  2  ,  —  x  n n  100  weight  Experimental seining T o d e t e r m i n e the m i g r a t o r y movements of y o u n g H i l s a , sampling beach  seine was  s t a r t e d in December 1983 and c o n t i n u e d to A u g u s t  by  1984.  T h e M e g h n a R i v e r between T a r p a c h a n d i and C h i r a r c h a r of N o r t h C h a n d p u r , shown in t h e F i g u r e 2, seining  was  conducted  w h e n s e i n i n g was beach  seine  samples. Each  was  selected  except  as the s t u d y  i n the months of A p r i l ,  o n l y monthly d u e to r o u g h  (150  ft x  20 f t x  1.8"  G e n e r a l l y , more t h a n one  haul involved  area.  was  h a u l was  to  made to o b t a i n  T h e net was  collect samples.  t h e n t u r n e d and p u l l e d  t h e boat f o r a few  then  arc  Figure  the  boat  in an  towards  the  minutes,  shore  as  and  was  shown  in  3.  F i s h c a p t u r e d b y t h i s method were p l a c e d i n .a p l a s t i c b a g , on  i c e , and  other clupeid  June,  experimental  employed  i n t h e d i r e c t i o n of r i v e r flow b y by  An  and  s t r e t c h i n g the net p e r p e n d i c u l a r to t h e s h o r e u s i n g  a s p e e d boat with o u t b o a r d e n g i n e .  drawn  May  weather.  mesh)  Fortnightly  t r a n s p o r t e d to the l a b o r a t o r y  species. Gadusia  lateral band  and  Juvenile chapra  on  Hilsa  was  the  basis  l a r g e r scales in H i l s a .  to s e p a r a t e t h e  packed  Hilsa  from river  distinguished  from  the  of  spots  along  five  dark  Furthermore,  the  to c o n f i r m the  9  FIGURE  3.  C o l l e c t i n g samples by e x p e r i m e n t a l  beach s e i n e at  area i n the R i v e r Meghna of North Chandpur,  Tarpachandi  March 6 ,  1984.  10  11  identification  of  the  species  Hilsa  ilisha,  meristic  counts  (lateral  line s c a l e s , d o r s a l f i n r a y s , p e c t o r a l f i n r a y s , a n d  n u m b e r of  of  before  starting  young  Hilsa  a  few  count  specimens  and  measured  measure to the  in each  sampling  specimens.  nearest  were  Total  taken  lengths  millimeter, u s i n g  the  of  scutes) to  were  same methods followed  for adult Hilsa.  2.3  F i s h e r m e n samples of j u v e n i l e s During fishery  w i n t e r months  for  juvenile  ( D e c e m b e r to A p r i l )  Hilsa  (called  "jatka")  F i s h i n g o c c u r s i n water d e p t h s g r e a t e r t h a n of  the  experimental  J a t k a were p r o c u r e d of fishermen's mize  bias  different net.  seining.  gears  selectivity  the  collections  as gill n e t , boat  t y p e s of gear  Barisal  while the samples of P a k s e y and a r e a s in B a n g l a d e s h . were  preserved  The  in plastic  the  were  5.  made  T o minifrom  encircling  the seine  J u v e n i l e s were  (March-April; July-August)  from  R a j s h a h i shown in F i g . 2.  The  juveniles  in  downstream  areas,  R a j s h a h i r e p r e s e n t e d t h e f i s h in u p p e r  samples o b t a i n e d b y p u r c h a s e bottles  with  10%  formalin.  t o r y , all c o l l e c t e d samples were m e a s u r e d and the previous chapter.  caught  from t h e c a t c h e s  Chandpur.  are shown in F i g s . 4 and  represented  rivers.  commercially  seine n e t , and  t h e f i s h m a r k e t s of B a r i s a l , P a k s e y and of  of  from the market at C h a n d p u r and  gear such  Bangladesh  10 f e e t , b e y o n d the limits  Samples  also p r o c u r e d d u r i n g t h e peak seasons  samples  in  gear in the M e g h n a R i v e r of N o r t h  from  The  beach  t h e r e i s a commercial  from In  fishermen  the l a b o r a -  weighed as d e s c r i b e d in  FIGURE  4.  Fishermen c a t c h i n g j u v e n i l e H i ! s a by boat s e i n e i n t h e Meghna R i v e r of North Chandpur, March 6 ,  1984.  13  14  FIGURE  5.  Fishermen o p e r a t i n g e n c i r c l i n g s e i n e i n t h e Meghna R i v e r of North Chandpur, A p r i l 2 5 ,  1984.  15  16  2.4  E x p e r i m e n t a l gill To  obtain  addition  to the  netting information results  experimental drift  shown  1983 had  distribution  from  analysis  of  of  conducted  juveniles,  fishermen's  Nets  were  c o n t i n u i n g to A u g u s t  a total l e n g t h of 630  fastened together.  set f o r t n i g h t l y ,  1984.  ft and  The  The  starting  multifilament  consisted  of nine  nets, and  l e n g t h of t h e panels was  2 1/2  inch  depth  of 12 f e e t .  The  net was  16 foot  outboard  speed  boat,  hours.  D i r e c t i o n of movement was  90 feet f o r the 3 to 5 i n c h  t h e r i v e r in t h e p e r i o d  in  drift  panels  p r e s e r v e d in an ice box,  and  weight  migration,  Otolith To sagittal  split  located.  gill  net  ranged  in  stretch,  45 feet f o r the 1 to n e t s , with a c o n s t a n t  gilling  with  the  tide-dependent. low  brought study  current for  The  tide.  net was  Catch  two  set in  of t h e  net  to t h e l a b o r a t o r y f o r l e n g t h  the  direction  direction of  (downstream  juvenile  Hilsa  in  or the  recorded.  interpretation determine otoliths  the  were  age  and  removed  open  the  Under  head a  and  hatching  from  t h e M e g h n a R i v e r in B a n g l a d e s h . to  drifted  h i g h and  To  e x p e r i m e n t a l d r i f t gill net was  2.5  and  and  measurements.  October  set in the r i v e r off C h a n d p u r from t h e  of both  was  of  catch,  in t h e M e g h n a R i v e r  a s c e n d i n g o r d e r of mesh sizes from 1 i n c h to 5 i n c h e s diamond  upstream)  in  T h e s t u d y a r e a was between C h a n d p u r a n d Nilkamal  in F i g . 2.  and  obtained  size  gill net sampling was  of N o r t h C h a n d p u r . as  on  A  expose  binocular  495  date  juvenile  from  s h a r p s t i f f - b l a d e d k n i f e was  used  the  were  cavities  Hilsa  Hilsa,  collected  dissecting  juvenile  of  in w h i c h  microscope  they  sagittal  otoliths  17  were  removed from  t h e c a v i t i e s with  forceps.  P r i o r to r e m o v i n g  o t o l i t h s , H i l s a were m e a s u r e d to t h e n e a r e s t millimeter. from  2.1 cm  specimens  to  were p r e p a r e d  G e e n (1981). compound cation  otoliths  (left  and  f o r examination as d e s c r i b e d  of 400x.  microscope Of  t h e 495  as u n r e a d a b l e .  using transmitted  employed  points clearly  otoliths  to estimate age of j u v e n i l e and  Miyamoto,  along  readings  the postrostral  viewed.  and  examined,  at a m a g n i f i -  113  otoliths  were  with  a  calibrated  axis  of  rings  and  also  comparisons  were made.  were  made  wherever increments  at  selected  or rings  the  of t h e otolith  t h e s e were u s e d  were  and  indirect  radius  with  to estimate t h e total  otolith.  To  counts,  find  out t h e  paired  t-test  T o determine t h e date of h a t c h i n g , t h e method (1981) was f o l l o w e d .  age  determinations  of modal l e n g t h s were a n a l y z e d  based  F o l l o w i n g t h e method of  otoliths  in t h e whole  direct  of T o w n s e n d a n d G r a h a m  progression  on  the proportion  present  between  validate  Hilsa.  T h e a v e r a g e width of i n c r e m e n t s i n t h e r e a d a b l e areas  difference  method  b y Neilson  Otolith l e n g t h was m e a s u r e d from t h e c e n t r e  r e a d a b l e and u n r e a d a b l e zones;  To  of all  d i r e c t a n d i n d i r e c t c o u n t s ( R a l s t o n a n d Miyamoto 1983) were  calculated,  number  right)  micrometer.  Both  Ralston  ranged  light  t h e n u c l e a r a r e a to t h e t i p of t h e p o s t r o s t r u m  ocular  was  Both  Sizes  O t o l i t h s were m e a s u r e d , and g r o w t h r i n g s c o u n t e d , with a  binocular  discarded of  17.5 cm.  the  on 1214 s p e c i m e n s .  by by  otolith  readings,  the Peterson  In a d d i t i o n , two  validation  the  Polygon experi-  m e n t s , ( F i g s . 6,7) as d e s c r i b e d b y C a m p a n a et a l . (1982) were c a r r i e d out  to determine  whether the growth increments  i n otoliths  of  Hilsa  18  FIGURE  6.  Intraperitoneal  tetracycline  of j u v e n i l e H i l s a .  innoculation  19  FIGURE  7.  S a l i n e / t e t r a c y c l i n e immersion of j u v e n i l e H i l s a .  experiments  21  22  are  daily or not.  One involved  injection of tetracycline, the other  immersion in saline/tetracycline solution. the  Also,  wild  juveniles  Meghna R i v e r were reared in a pond at the Fisheries  Station at Chandpur f o r the same purpose.  from  Research  23  3.  3.1  RESULTS  S p a w n i n g time as i n d i c a t e d b y female s e x u a l c o n d i t i o n Gonadosomatic i n d i c e s of female H i l s a i n t h e M e g h n a arine  and  depicted  marine  h a b i t a t s , were  i n F i g . 8.  indicate  three  (8.0).  T h e index  The  peaks:  c a l c u l a t e d f o r each  gonad  index  in O c t o b e r  values  values  (11.9),  of e s t u a r i n e  of  marine  reaching  Hilsa  exhibit  a peak  a  rise  in August  noted in F e b r u a r y  (0.8) with  In B a n g l a d e s h , w i n t e r  A  February  River  (8.9),  two  and are  and  peaks;  value  starting  small ascent  a fall i n M a r c h  in J u n e  of value  was  and also  (0.4).  s t a r t s i n December a n d e n d s i n A p r i l , a n d The  R i v e r habitat s u g g e s t that t h e r e a r e t h r e e  major s p a w n i n g times of H i l s a . spawn in winter  June  one in  t h e monsoon p e r i o d commences i n May a n d terminates i n N o v e m b e r . three peaks in the Meghna  Hilsa  On t h e o t h e r h a n d , t h e v a l u e s  in t h e  (7.9).  month  of M e g h n a  H i l s a show  M a r c h (9.8) a n d a n o t h e r in J u n e ( 6 . 9 ) .  River, estu-  T h e F e b r u a r y peak i n d i c a t e d many H i l s a  s e a s o n , while t h e p e a k s i n J u n e and O c t o b e r  H i l s a also spawn two times i n t h e monsoon  revealed  season.  B a s e d on 8 months d a t a , i n e s t u a r i n e samples t h e r e  was  evidence  of o n l y two s p a w n i n g p e r i o d s p e r y e a r , i n M a r c h w h i c h was d e n o t e d as winter monsoon  spawning,  then  spawning.  another  T h e r e was  s a m p l i n g of e s t u a r i n e h a b i t a t . values Meghna  showed River,  a  similar  that  was  considered  no S e p t e m b e r , O c t o b e r  and  as t h e  November  H o w e v e r , as t h e r i s e a n d fall of index  pattern  the possibility  c o u l d be p o s t u l a t e d .  in June  in e s t u a r i n e  of a t h i r d  F u r t h e r , although  habitats  spawning  and  in the  in the estuaries  e a r l y monsoon s p a w n i n g ( J u n e )  24  FIGURE  8.  Seasonal f l u c t u a t i o n s o f Gonadosomatic (with standard e r r o r ) habitats  Index  of female H i l s a i n t h r e e  ( R i v e r Meghna, e s t u a r i n e and m a r i n e ) .  25  -O  MEGHNA RIVER  -•  ESTUARINE  -Q  MARINE  \)  MONSOON  MONTHS  26  o c c u r s i n both t h e h a b i t a t s , w i n t e r s p a w n i n g was e a r l i e r i n t h e M e g h n a River  (February)  mature  estuarine  than fish  in estuaries were  (March).  not a l l m o v i n g  This up  indicates  to spawn  that  later i n  Meghna. The  index  values of marine  Hilsa resulted  in a different  f r o m t h e v a l u e s of e s t u a r i n e a n d M e g h n a R i v e r h a b i t a t s . data  i n September;  Hilsa.  August  showed  a  peak  picture  T h e r e were no  i n maturation  of marine  T h e r e i s a p o s s i b i l i t y that no s p a w n i n g o c c u r s i n t h e s e a , a n d  all t h e f i s h  which  mature t h e r e make t r i p s into r i v e r s o r e s t u a r i e s to  release e g g s .  3.2  Hatching  date a n d e a r l y  Until India  now,  growth based  no work  or in Bangladesh  c o u n t i n g t h e daily now been u s e d  h a s been  done  to determine  growth  age  l e v e l s of i n f o r m a t i o n ( R a d t k e  and hence  growth  Hilsa rings  will  a n d p r e c i s i o n of  compared  s p a w n i n g time as i n d i c a t e d  new  a n d Dean 1982).  the hatching  be  have  T h e d i s c o v e r y of d a i l y r i n g s i n  date,  h a s been made to determine t h e of j u v e n i l e  Hilsa  of t h e M e g h n a  R i v e r in Bangladesh by counting daily growth r i n g s in otoliths. information  by  t h e age of l a r v a l a n d j u v e n i l e  to p r o v i d e f i s h e r y b i o l o g i s t s with  In t h e p r e s e n t s t u d y , an attempt age,  Daily  (1971) i n c r e a s e s t h e r e s o l u t i o n  d e t e r m i n a t i o n , a n d promises  scientist in  t h e age of j u v e n i l e  s u c c e s s f u l l y to determine  by Pannella  by any fishery  rings in otoliths.  f i s h of o t h e r s p e c i e s ( C a m p a n a 1983). otoliths  on otoliths  with  data  previously  presented  b y s e x u a l c o n d i t i o n of t h e a d u l t s .  This on  27 3.2.1  Otolith  development  Figure 9 Hilsa  indicates different  otoliths  length. soid  The  in  side.  of  fish  otolith  shape,  ranging  of the  with  a  major  group.  Otoliths  r o s t r u m and otoliths  was  also of  distal  had  well d e v e l o p e d  side  reflected  Rarely, Variable  the  the  otoliths had  cm  a  can  Inside t h e  shape and  seen  nucleus,  this  ellip-  proximal forma-  position of  of  this  well  size  developed  of  Hilsa  post-rostrum,  at  the  with  and  depression,  certain  focus or  a  angles  of  primordium  ( F i g . 10). there  primordia  is  was  length group ( F i g . 9 c ) ,  typical  be  total  of the The  of  cm  flat  are in  two  fish  primordia otoliths  in  were  Hilsa  first  N e i l s o n (1984) i n Salmo q a i r d n e r i a n d O n c o r h y n c h u s but  9.3  the distal side, a slight  nucleus,  light.  be seen  in  ( F i g . 9b)  the  and  beginning  antirostrum, pararostrum On  to  ( F i g . 9a).  In the 4.1  attained  also a s e r r a t e d e d g e . presumably  be seen  cm  antirostrum.  cm  development  smallest H i l s a examined  evident  3.2  in t h e  2.1  In t h i s size g r o u p of f i s h , t h e  excisura  can  from  convex  t i o n of t h e a n t i r o s t r u m c a n  the  stages  the  first  discovery  of  two  ( F i g . 11).  described  by  tshawytscha,  primordia  in  Hilsa  otoliths.  3.2.2  Age  of j u v e n i l e As  Hilsa  H i l s a is a f i s h  of t h e t r o p i c a l e n v i r o n m e n t , t h e  r i n g s i n otoliths are faint in comparison ate f i s h e s .  Nevertheless, they  form  to those  clearly  from  countable  growth temperseries,  28  FIGURE  9.  O u t l i n e s o f H i l s a o t o l i t h s showing t h e i r Respective t o t a l  l e n g t h s of f i s h were:  B 3 . 2 cm; C, 4 . 1  cm; D,  G,  8 . 4 cm; and H,  5 . 3 cm; E,  9 . 3 cm.  6.1  development. A,  2.1  cm; F,  cm; 7.1  cm;  A l l o u t l i n e s same  m a g n i f i c a t i o n ; o t o l i t h H i s 112 urn maximum l e n g t h . O t o l i t h of F i g . b:  i=rostrum,  9 a:  i=antirostrum,  ii=antirostrum; c:  ii=antirostrum, v = s e r r a t e d edge.  iii=pararostrum,  i i = e x c i s u r a major; i=rostrum,  iv=postrostrum,  29  30  FIGURE 10.  Ground and p o l i s h e d s a g i t t a l o t o l i t h from Meghna j u v e n i l e H i l s a ( 4 . 3 cm) showing p r i m o r d i u m . (magnification  410x).  River  32  FIGURE 11.  Central  area of ground and p o l i s h e d s a g i t t a l  from Meghna R i v e r j u v e n i l e H i l s a  (6.1  double primordium  410x)  (magnification  otolith  cm) showing a  34  particularly and in  13).  in  the  The  Table 1  counts.  counts  and  By  central  region  of r i n g s  F i g . 14;  of  the  otoliths  w i t h i n otoliths  these  combine  are  direct  (Figs.  summarized  and  i n c r e a s e of 2 cm  Up  to a l e n g t h of 12 cm  in l e n g t h f o r e v e r y  i n total l e n g t h , showed 33 r i n g s , a n d h e n c e was one  can  probably  month be  old.  used  The  the  lengths  count.  If t h e c o u n t s  increase size  over  at  in  growth  which,  as  12 cm  rings  in F i g . 14  rate  after  of  a  probably  Hilsa  more  of  12 cm,  later  otoliths  up  to  171  difficult  to  suggest  an  l e n g t h s of 12  are c o r r e c t , t h e y  in  collected,  reliably  become  length  described  rings  fairly  d a y s ( a p p r o x i m a t e l y 6 months old) and  approxi-  smallest H i l s a  growth  to estimate age  a steady  (i.e.,  2.1  over  study,  rings  1 month).  just  In t h i s  30  t h e r e was  mately  At  indirect  a s s u m i n g t h e i n c r e m e n t s were formed d a i l y , t h e f i s h  a r e aged as s h o w n .  cm  12  cm.  which  section,  is the  the  young  m i g r a t e t o w a r d s the s e a . A the in  p a i r w i s e t-test was  direct which  and a  indirect  complete  (direct count)  used  to test f o r d i f f e r e n c e s  ages. series  For of  this  purpose  increments  between  some  otoliths  be  counted  the  indirect  could  were also s u b j e c t e d to estimates b y  method, (by counting increments only over measured s u b d i v i s i o n s of t h e whole s e r i e s ) . by was  the two  methods was  therefore  indirect  The  method  assumed in  difference  not  significant  that  older  between  fish  the  (p=0.1943, n=25).  estimation  (<12  a c c u r a t e , b u t it becomes p r o g r e s s i v e l y  ages a r r i v e d  cm)  may  harder  of  age be  by  at It the  reasonably  at l a r g e r  sizes.  35  FIGURE 12.  Ground and p o l i s h e d s a g i t t a l juvenile Hi!sa (Bar =/um  2.5).  (3.7  o t o l i t h from Meghna  cm) showing the growth  rings  River  36  37  FIGURE 13.  Ground and p o l i s h e d s a g i t t a l (11.1  otolith  of j u v e n i l e  cm) from Meghna R i v e r showing the growth  (Bar =/um  2.5).  Hilsa  rings  38  39  FIGURE 14.  Number of d a i l y r i n g s i n o t o l i t h s of H i I s a of d i f f e r e n t vertical  sizes.  l i n e s are r a n g e s .  juvenile  C i r c l e s are means, Data i n T a b l e  L i n e f i t t e d by eye to l e n g t h s up t o 12 cm.  1.  40  o  41  TABLE 1.  Number of growth r i n g s counted i n o t o l i t h s of j u v e n i l e  Hi!sa,  c o l l e c t e d from t h e Meghna R i v e r of North Chandpur i n 1983-1984.  Total Length - cm.  Ring Counts  Estimated Age  Sample  Mean  Class Intervals  Mean  Range  Days  Months  Size  2.71  2.1-3.0  44  33-57  44  1.46  18  4.20  3.1-5.0  62  37-84  62  2.06  96  5.93  5.1-7.0  85  55-136  85  2.83  96  7.93  7.1-9.0  115  85-158  115  3.83  36  10.16  9.1-11.0  151  86-216  151  5.03  55  11.96  11.1-13.0  171  130-217  171  5.70  46  13.80  13.1-15.0  176  133-227  176  5.86  25  15.96  15.1-17.0  186  140-229  186  6.20  8  17.50  17.1-19.0  234  234  234  7.80  1  42  A  direct  coming  from  counted from  count  was  fish  possible  i n otoliths  of t h e 4.9 cm  size  fish  below  Validation Peterson)  4 cm  of  Attempts various  in total l e n g t h ,  age  treatments  through  The  injected  length,  of  died  which  Saline  juveniles within  had  been  immersed  the  a pond original  mortality  which  ful,  were  ranged  held  very  with  (100 mg/kg from  in .01% N a C l .005%  a n d small  sample  the  sizes  H i l s a h a d been  but variation  pond  coupled  precluded  their  This held  tetracy-  solution  tetracycline.  were  in  sensi-  In a s e p a r a t e  In a t h i r d e x p e r i m e n t , samples  placed  in  7.5 to 17.5 cm in  only  Hilsa,  by  body wt).  survived  fish  (<7 cm)  young  study  saline,  Hilsa  treated  approximately  juveniles  some hope of f u t u r e An  juvenile  H i l s a were immersed  containing  any young  in this  15-20 minutes of i n j e c t i o n .  added  a n d came  otolith i n t e r p r e t a t i o n s  injection  d a t i n g otolith i n t e r p r e t a t i o n . that  so a g i n g  Juveniles proved  Hilsa  intraperitoneal  30-60 m i n u t e s . from  all d i r e c t  counts.  wild-caught  Juvenile  experiment, juvenile to  Of  long,  (tetracycline,  were made to validate  to h a n d l i n g .  cline  group.  determinations  e x p e r i m e n t a l p o n d s at C h a n d p u r . tive  to 295/um  o t o l i t h s (n=25), 75% were u n d e r 190/um l o n g  was b a s e d on both d i r e c t a n d i n d i r e c t  3.2.3  up  up  to  collected  i n size of with  high  u s e in v a l i -  was h o w e v e r t h e f i r s t  time  in c a p t i v i t y , and there is  success.  i n d e p e n d e n t method of age validation was more s u c c e s s -  namely  the Peterson  Polygon  method  which  attempts to  43  follow the g r o w t h of a c o h o r t of f i s h length frequency plots. distribution at  The  of  H i l s a collected  f i r s t mode at 5.0  w h i c h s h i f t e d to 7.0 Up  F i g u r e 15 shows the l e n g t h f r e q u e n c y  of j u v e n i l e  Chandpur.  cm  in J a n u a r y  from  cm  and  the  Meghna  2.0  cm  in each month.  seen  in December  to 9.0  cm  in F e b r u a r y .  value  progression cm  progressed  to  in 30 d a y s .  rings,  which  v a l u e s at 2.0 growth  formed  daily  cm  p r o g r e s s i o n of modal v a l u e s  and  Hatching  dates  specimen otoliths  in  by from  ring  that  in  April.  size group  with t h e  the  was  date  observed 30  shift  growth  i n modal  be c o n c l u d e d  of  Hilsa  ages  formed)  was  number  of c a p t u r e .  are  of y o u n g  the  date  of  growth  F i g u r e 16  fish  are  when  the  rings shows  that  usually  back-calculated for  s t r u c t u r e , so c a l c u l a t e d , of j u v e n i l e H i l s a w h i c h  each  in  the  the  age  were c a p t u r e d  in d i f f e r e n t months i n the M e g h n a R i v e r of N o r t h C h a n d p u r . f i s h h a t c h e d between e a r l y A u g u s t  the about  T h u s , it can  determined  the  grow  it was  subsequent  juvenile  The  Overall,  H i l s a had  (or more c o r r e c t l y  subtracting the  cm  otoliths  h a t c h i n g date  growth  cm  p r e v i o u s section  p e r 30 d a y s .  rings  valid.  The  12.0  In the  is c o n s i s t e n t  probably  first  cm  of modal v a l u e s s u g g e s t s that t h e f i s h  t h a t t h e o t o l i t h s of the 2.0  the  1.0  at t h e rate  o b s e r v e d i n between F e b r u a r y (9.0) and March (10.0).  modal  2.0  A  River  was  to F e b r u a r y , t h e p r o g r e s s i o n of modal v a l u e s was  was  3.2.4  i d e n t i f i a b l e as a mode in  The  and e a r l y N o v e m b e r were f i r s t  44  FIGURE 15.  Length f r e q u e n c y d i s t r i b u t i o n of j u v e n i l e Hi 1sa c o l l e c t e d from the Meghna R i v e r North Chandpur,  1983-1984.  of  JANUARY N » 168  FEBRUARY N - 181  1  r MARCH N '298  APRIL N* 432  8  9  10  II  12  TOTAL LENGTH - cm  13  14  13  16  17  18  46  FIGURE 16.  Date of f o r m a t i o n of the f i r s t o t o l i t h growth axis) left.  in juveniles collected in different  ring  months  (horizontal  i n d i c a t e d at  47  DEC  25  N  20 10 •  r-mTJAN  IS •  N «73  10 • 5 •  ih4  FEB  IS -  i  i  N«68  10 • 5 •  MB MAR  IS •  _ N'42  10 •  s •  1  10 •  o  73-  RE  is •  > o z  80-  u_  23-  UJ Z>  s •  -QAPRIL N»94  -0=  EL  MAY  1  - i  o  60-  TA  40-  z  20-  ER  UJ  30-  UJ u o_  '42  u  r  JUNE  N • 6  i  i  N«I0  1  "T  J U LY N > 29  2010 60-  AUG N * 16  4020AUG  15 -  SEPT  OCT  NOV  DEC  JAN  FEB  MAR  APR  MAY  LU  JUN  1  1  JUL  N • 382  TOTAL  10 8 -  JUL  AUG  SEPT  r-, OCT  NOV  DEC  JAN  fin  FEB  MONTHS  MAR  APR  MAY  JUN  JUL  48  captured  i n December.  of late O c t o b e r  spawning  were dominant in t h e months of December a n d J a n u a r y .  November  hatchers  but their  appeared  disappearance progeny  The progeny  i n peak  was  abundance  observed  in F e b r u a r y ,  in M a r c h .  In  April,  both  the  of late monsoon and w i n t e r s p a w n i n g were a b u n d a n t , b u t  i n May t h e y completely d i s a p p e a r e d from t h e r i v e r . disappearance, the progeny  After their  of p o s t - w i n t e r a n d e a r l y  monsoon  o c c u p i e d t h e same habitat i n May to A u g u s t . The  bottom  distribution  panel  of j u v e n i l e  it becomes c l e a r that in  the Meghna  (October),  Hilsa from  Hilsa  River:  and  hatching  indicates  that  some  t h e t r i m o d a l age  all t h e samples.  monsoon  (January  date  indicates  From  spawn t h r e e times on a l a r g e  early  winter  extended  throughout  of F i g . 16  and  (August  Hilsa  also  1983  (June), March). -  spawn  scale  monsoon  Besides, the  July on  late  this  1984) a  small  clearly scale  t h e y e a r i n t h e M e g h n a R i v e r of N o r t h C h a n d p u r in  Bangladesh.  3.3  M i g r a t o r y movements of j u v e n i l e s B e c a u s e k n o w l e d g e about m i g r a t o r y movements of j u v e n i l e H i l s a as well as of a d u l t  Hilsa  is necessary  b o t h s t a g e s s u s t a i n a commercial study  the migration  (experimental catch  seine  management  f i s h e r y ) , an attempt  of j u v e n i l e s and  f o r intelligent  gillnet),  on  t h e basis  as well  as  by  of  has been made to research  fishing  examination  of t h e  i n fishermen's g e a r , with s p e c i a l emphasis on t h e M e g h n a  of N o r t h  Chandpur.  (since  River  49 3.3.1  Length frequency fishermen's g e a r Monthly  analysis  samples of beach  examined  f o r a nine month  measured  was  and 1.0  1439,  fishermen's cm  gear  intervals,  inhabiting  fishermen's  experimental  seine and  period.  beach  seine  respectively.  and  their  The  The  beach  less t h a n  gear  The  percentage  and  fishermen's gear total  number  were  of  of which 757 and 682 were from beach  as shown in F i g . 17. Hilsa  of  fish  were  fish seine  grouped  in  frequencies calculated,  seine d a t a r e p r e s e n t e d j u v e n i l e  10 ft d e p t h s ,  represented  while  the  the  Hilsa  samples in  of  deeper  water (>10 f t ) . Length-frequency  d i s t r i b u t i o n s of b e a c h - s e i n e d  s i n g l e modal peak in December J u n e (4.0) , J u l y  (5.0) , and  January  6.0),  and  (4.0 and  6.0).  August  February  A l l size groups  i n t h e c a t c h e s of beach  (5.0), March  seine.  a r e the i n h a b i t a n t s of s h o r e  ( 8 . 0 ) , May  had  (4.0),  8.0)  to 8.0  cm  and  April  (3.0  were r e p r e s e n t e d  E v i d e n t l y y o u n g H i l s a (<8.0 and  a  (5.0) , b u t w e r e bimodal in  (4.0 and  from 3.0  fish  shallow  areas  in the  cm)  Meghna  River. A g a i n , monthly exhibited  bimodal  length frequency  peaks  modal peak i n J a n u a r y  in A p r i l  r a n g e of modal v a l u e s was 7.0  the  juveniles  s h o r e and which  are  deeper  shallow a r e a s . generally  and  12.0)  and  a  gear single  ( 7 . 0 ) , F e b r u a r y ( 9 . 0 ) , a n d M a r c h (10.0).  The  in  (7.0  d a t a of fishermen's  river Boat  operated  cm to 12.0  are  larger  cm  which indicates  than  those  in  the  seine nets as shown in F i g . 4, i n the  middle  of  the  river  in  50  FIGURE 17.  Frequency d i s t r i b u t i o n of j u v e n i l e Hi 1sa i n d i f f e r e n t depth zones i n the Meghna R i v e r of North Chandpur,  1983-1984.  DECEMBER N» 140  60 40  APRIL N» 68  20 0 JANUARY N* 90  N » 324  40 20  ^-1, , R W h  0 N>60  60  MAY N«76  40 20 0 60  FEBRUARY N= 49  JUNE N '36  40 20 0 60  N = 105  JULY N« 88  40 20  r/r7i_ MARCH N= 7  60 40  AUGUST N«203  ;  20  rJ  3  4 5  6 7 8 9 10 II 12 13 14 IS 16 17 18  N » 193  3 4 5 6 7 8 9 10 II 12 13 14 IS 16 17 18  TOTAL  LENGTH - cm  •  BEACH SEINE CATCH FROM RIVER AREAS (< 10ft. DEPTH )  P7] \CA  FISHERMEN'S CATCH FROM RIVER AREAS O l O f t DEPTH )  52  deeper  w a t e r , have  January deeper  a small mesh  at 7.0 cm p e r h a p s water.  (1/2-1").  T h e mode i n  i n d i c a t e s t h e size of immigration to  In J a n u a r y ,  g r a t e d to d e e p e r  size  t h e p r o g e n y of late monsoon  immi-  water from t h e s h o r e a r e a , while i n A p r i l t h e  p r o g e n y of w i n t e r s p a w n i n g showed t h e i r a p p e a r a n c e i n d e e p e r water.  T h e s h i f t i n g of mode from J a n u a r y  indicate  the r i v e r  residence  i n May  documented  juveniles out  of t h e r i v e r .  peak  may  disappeared indicate  of o l d e r  juveniles  i n May, t h e modal  t h e size  at m i g r a t i o n  the river. Prior  juvenile and  in A p r i l  (12.0)  T h e n o n - a v a i l a b i l i t y of  the migration  A s t h e fish  at 12.0 cm  from  growth.  (7.0) to A p r i l  to t h e p r e s e n t  Hilsa  i n December was  fishermen  fishermen's  observations,  in Bangladesh.  gear  unknown  the availability to f i s h e r y  T h e availability  in January  clearly  indicate  of  biologists  of f i s h the  to t h e  migratory  movements of j u v e n i l e H i l s a ; i n December t h e r e was no e v i d e n c e of  the occurrence  gear.  Evidently  shallow  river  the deeper The  juvenile  of  high  shore and  to a v o i d t h e s t r o n g c u r r e n t s of  fish  hatched  i n late monsoon a n d i n t h e b e g i n n i n g of  into d e e p e r  water of t h e r i v e r  ( s u p p o r t i n g the Jatka fishery) until they  about  of fishermen's  river.  12 cm  smaller s i z e d to  in the catches  H i l s a below 8.0 cm p r e f e r  areas, perhaps  w i n t e r all moved there  of j u v e n i l e s  before they  fish  downward  may flow  migrated  also migrate i n May.  remained  reached  to s e a i n May.  from On  and  the deeper  a size A few  river due  the c o n t r a r y , t h e fish  53 hatched  in late  i n s h o r e and  3.3.2  winter  and  which  remain  t h e r e but a r e c a r r i e d  at that  E x p e r i m e n t a l gillnet Length  time of y e a r  frequency  experimental  recorded  drift of  occurred  gillnets,  juveniles  of  in A p r i l  assumptions  caught  only deeper  swift, they  do  not  downstream to the s e a .  Hilsa  in the  deeper  water  Meghna R i v e r of N o r t h C h a n d p u r , t a k e n b y  in F e b r u a r y .  cessation  is v e r y  of j u v e n i l e  are  shown  (10.0 cm)  in F i g . 18.  in  J u v e n i l e s were a b u n d a n t i n A p r i l ,  and  commercial ( F i g . 17).  of t h e a u t h o r was  deeper  first was  disappeared.  the  The river  thereafter they suddenly the  were  sampling  ft depth) in the  appearance  monsoon  at small s i z e s ; p o s s i b l y when t h e y move into  water,  (>25  early  This corresponded  fishing  for  Prior  to  "Jatka" the  which  experiment,  that d u r i n g t h e monsoon  with also the  season  ( M a y - O c t o b e r ) f i s h e r m e n do not o p e r a t e the y o u n g H i l s a c a t c h i n g net b e c a u s e  the r i v e r i s f l o o d e d and  T h i s might have a c c o u n t e d f o r why  the c u r r e n t s are s t r o n g .  j u v e n i l e s in t h e monsoon h a v e  not been r e c o r d e d b y any a u t h o r in B a n g l a d e s h . is  clear  from  communication  experimental with  the  a v a i l a b l e in the d e e p e r men  netting  fishermen river  early  and  that  Now  also  from  juvenile  in the  h o w e v e r , it personal  Hilsa  season;  are  the  not  fisher-  know t h i s , a n d c o n s e q u e n t l y , t h e y do not o p e r a t e t h e i r nets  then.  Experimental  gill  netting  in  deeper  water  s u p p o r t s t h e c o n c l u s i o n that the j u v e n i l e s migrate f r o m the r i v e r M e g h n a to o t h e r a r e a s .  As  therefore  at that  t h e season  time  advances  FIGURE 18.  Frequency d i s t r i b u t i o n of j u v e n i l e H i l s a and a d u l t Hi Is caught by e x p e r i m e n t a l o f North Chandpur,  g i l l net i n the Meghna  1983-1984.  River  OCTOBER '83  r~i n NOVEMBER  DECEMBER  5-  r~i  0  JANUARY  30  FEBRUARY  50 V o  z  UJ 3 O  MARCH  30  T~l  u  APRIL  IE  MAY  0 JUNE  3-  JULY  AUGUST ' 8 4  n . n n ... TOTAL  LENGTH - cm  56  the  fishermen  use  clap  nets,  gill  nets,  and  seine  nets  of  downstream  or  b i g g e r mesh s i z e s f o r c a t c h i n g a d u l t H i l s a .  3.3.3  Gilling  direction  To  examine w h e t h e r j u v e n i l e  upstream,  the  experimental evident were  gilling  drift  that the  facing  direction  net  fish  was  (9.0-11.0 cm)  were  while  facing  of  from  reached  more t h a n  The  f i s h u n d e r 12.0  cm,  cm  in  7th  April  From  F i g . 19  it is  in total  j u v e n i l e s less  upstream.  11.0  taken  13 - 17 cm  the  with the s u g g e s t i o n of the p r e v i o u s had  fish  recorded.  ranging  downstream,  H i l s a migrate  This  length  than  finding  11  coincides  s e c t i o n that j u v e n i l e  started  to migrate  f a c i n g u p s t r e a m , may  cm  which  downstream.  have b e e n h o l d i n g  p o s i t i o n ; t h e l a r g e r f i s h , f a c i n g d o w n s t r e a m , c a n not have been doing  3.3.4  so.  J u v e n i l e s i z e s in d i f f e r e n t r e g i o n s of R i v e r As  a f u r t h e r c h e c k on  their  direction  Meghna of m i g r a t i o n ,  n i l e s were sampled from the u p p e r , middle and  juve-  downstream areas  i n B a n g l a d e s h , in each of f o u r months d u r i n g the peak season of Jatka availability. F i g . 20.  Monthwise mean total l e n g t h s a r e  F r o m t h e f i g u r e , a g r a d u a l i n c r e a s e of mean  of o l d e r j u v e n i l e s was in  the  shown in  samples  of  observed  March  and  from u p p e r to d o w n s t r e a m April.  On  the  other  g r a d u a l d e c l i n e of mean l e n g t h s of small j u v e n i l e s was i n the samples of J u l y and  lengths  August.  The  areas  hand,  a  observed  gradual increments  of  mean l e n g t h from u p p e r to downsteam areas i n d i c a t e s t h e c o n g r e  57  FIGURE 19.  G i l l i n g d i r e c t i o n of . j u v e n i l e H i l s a caught g i l l net  i n the Meghna R i v e r on A p r i l  d r i f t i n g downstream d u r i n g sampling  7,  by  1984.  period.  experimental Boat was  DOWNSTREAM " i i  UPSTREAM  oo  59  FIGURE 20.  Mean t o t a l  l e n g t h of j u v e n i l e Hi 1sa i n the d i f f e r e n t  areas.  Upper areas - f i s h from the R i v e r Padma, c o l l e c t e d from Paksey and R a j s h a h i ; m i d d l e areas - f i s h from t h e Meghna, c o l l e c t e d from Chandpur; the e s t u a r y ,  River  lower areas - f i s h from  c o l l e c t e d from B a r i s a l .  60  •  v  UPPER AREA MIDDLE AREA LOWER AREA  13.0-  N » 743  11.0-  E u I  I  I  9.0-  e> 7.o z LU  < 5.0  rO  3.0-  I  \  1.0-  MARCH  APRIL  JULY  AUGUST  TIME  V  61 gation be and  of l a r g e r j u v e n i l e s i n t h e downstream  t h e r e s u l t of m i g r a t i o n Padma  Rivers.  of j u v e n i l e  Hilsa  areas, which from  may  the Meghna  In a d d i t i o n , t h e n o n - a v a i l a b i l i t y of l a r g e r  j u v e n i l e s i n t h e samples of J u l y a n d A u g u s t from t h e u p p e r a r e a showed  that  upstream was  although  when  downriver.  juvenile upper  may  river.  gilled  the smaller-sized  juvenile  were  ( F i g . 1 9 ) , t h e i r net movement  Also,  the larger  be t h e e v i d e n c e of e a r l y  size  gradient  winter  facing  over  time  of  smaller  spawning  in t h e  62  4. DISCUSSION 4.1  Spawning periods Day  (1873) was  grounds  and  the f i r s t  breeding  to attempt  season  of  Hilsa  to determine  ilisha  i n the  the  spawning  Indian  region.  S i n c e t h e n , much attention has been f o c u s s e d on the s t u d y of b r e e d i n g and In  bionomics of t h i s f i s h , Bangladesh,  index,  Shafi  determine based  1972,  et  ah  on  gonad  1958, and  De  by  I n d i a n and  Bangladeshi authors.  the s t u d i e s of o v a m a t u r i t y and  (1978)  the s p a w n i n g  on  (Pillay  based  both  and  Quddus  seasons  of H i l s a  size i n d e x  and  Nair  1958,  1980)  studied  ova  Pillay  et  aL_  (1984)  ilisha.  1963,  Mathur  1964,  size to  in India,  maturity studies, several  the s p a w n i n g  Menon (1950, 1951), C h a n d r a  attempted  Similarly,  authors  Ramakrishnaiah  seasons of t h e s p e c i e s .  I n d i a , many a u t h o r s , s u c h as N a i r (1939), H o r a and and  gonad  In  N a i r (1940), Jones  (1962), and B h a n o t  (1973), also t r i e d  to estimate t h e e x t e n t of t h e s p a w n i n g  seasons b a s e d on o c c u r r e n c e of  e g g s or juvenile Hilsa.  attempt  U n t i l now,  no  has  been made b y  any  a u t h o r , e i t h e r i n I n d i a o r i n B a n g l a d e s h , to s t u d y the s p a w n i n g  activ-  ites  river)  of  Hilsa  in  different  habitats  (marine,  estuarine  and  d u r i n g the same p e r i o d of time. Based Motwani  et  on  gonad  size i n d e x  a l . - (1957)  G a n g e s would  reported  and  ova  that  maturation studies in India,  the  breeding  of  Hilsa  in  the  a p p e a r to commence with t h e onset of t h e monsoon season  i n J u l y , with peak b r e e d i n g from S e p t e m b e r to December. Pillay  (1958)  has d e s c r i b e d the b r e e d i n g season in t h e H o o g h l y as from the b e g i n n i n g of  the  southwest  monsoon  to  November  and  again  from  January  to  F e b r u a r y or March. upper  s t r e t c h e s of the G a n g e s , the f i r s t commencing  lasting found  M a t h u r (1964) o b s e r v e d two s p a w n i n g seasons in the  u n t i l A p r i l with a peak d u r i n g M a r c h . to s t a r t in A u g u s t  October.  and  in F e b r u a r y  and  The second spawning  was  to terminate i n N o v e m b e r with a peak i n  A g a i n , in N a r b a d a in I n d i a , K a r a m c h a n d a n i (1961) f o u n d that  t h e main s p a w n i n g season commences in J u n e - J u l y and S e p t e m b e r , the peak b e i n g in A u g u s t . Pillay  and  Rosa  (1963)  suggested  F o r the G a n g a - H o o g h l y  that  there  may  s p a w n i n g seasons with a p e r i o d of time between: the  start  of t h e southwest  November,  and  Bangladesh,  a  second  monsoon which  c o n t i n u e s up  (June)  occurs  one  and  from  be  distinct b e g i n s at  continues through  January  to  March.  S h a f i et a l . (1978) c o n c l u d e d that t h e r e are two  seasons:  one  from  October.  Quddus  January  to  March  and  e_t a l . (1984) o b s e r v e d  the  other  that  Hilsa  to In  spawning  from  July  to  breeds  at  two  d i f f e r e n t times, J u n e to O c t o b e r with a peak in S e p t e m b e r and to  system,  two  which  to  December  March with a peak in F e b r u a r y . In  the present s t u d y ,  spawning  seasons,  Monsoon  breeding  continued breeding peak  a  period  started  to N o v e m b e r  with  in F e b r u a r y  corroborated  the  observations  of  Bangladesh  results Shafi  regarding  of H i l s a .  on  of time  peaks  indices,  between,  and of  in J u n e  (January) March. Indian  e_t a l . (1978) the  About  t h e gonad  two  and  and  The  and  establishment  t h e peak time  October,  terminated  (June) and  but  also  Quddus of  period  two  et  and  winter  in A p r i l  present findings  authors  distinct  were c o n s i d e r e d .  in the b e g i n n i n g of the season  b e g a n i n the w i n t e r  period  seasons  with  based  with  not  only  supported a l . (1984)  distinct  of s p a w n i n g ,  the in  spawning a  slight  difference their  was  noted  between  s t u d i e s were c o n f i n e d  their  w o r k s and  to d i f f e r e n t  the  river  present.  systems  s t r e t c h e s i n B a n g l a d e s h ( M e g h n a and Padma R i v e r ) . i n the p r e s e n t s t u d y , samples were t a k e n from e s t u a r i n e , and time  of  Hilsa  M e g h n a R i v e r ) with in d i f f e r e n t  t h a t r i v e r i n e and  an  habitats.  aim  in t h e  upper  three habitats (marine,  the  the  results,  e s t u a r i n e h a b i t a t s r e p r e s e n t e d two  spawning  it was  spawning  clear seasons  with t h r e e major time p e r i o d s , while the marine h a b i t a t showed period  of  maturation.  In  winter  spawning,  noted between the M e g h n a R i v e r H i l s a and  of  On the o t h e r h a n d ,  to determine  From  Both  a  slight  a peak  difference  was  t h e e s t u a r i n e H i l s a ; t h o s e in  t h e M e g h n a R i v e r spawn in F e b r u a r y whereas those in e s t u a r i e s spawn in March.  H e n c e , it may  ( R i c k e r 1950) populations  and  be  t h a t , like t h e F r a s e r R i v e r s o c k e y e  Ganges Hilsa (Ghos and  which  spawn  in t h e  upper  salmon  N a g p a l 1970), t h e r e a r e also stretches  and  in  the  s t r e t c h e s in the B a n g l a d e s h waters d u r i n g late w i n t e r months. f i n d i n g s s u p p o r t the o p i n i o n of Job slightly  variable  conditions.  from  to  place,  who  r e p o r t e d to v a r y  a few  single breeding  season  possibility  breeding been of  a  i n s t e a d of two  breeding,  p e r i o d is ecological  Melvin  (1984)  of H i l s a has  been  Islam and  the  Talbot  Indus ( P a k i s t a n ) , a  seasons.  of H i l s a i l i s h a in t h e  controversial  winter  (India) and  These  d e p e n d i n g on  F o r i n s t a n c e , K u l k a r n i (1950) and  in the r i v e r s Godavari  time  different  months to y e a r - r o u n d ,  (1958) o b s e r v e d  long  to  s t a t e d that the s p a w n i n g season  from  author.  Winter  due  R e c e n t l y , similar s u g g e s t i o n s were made b y  in Bangladesh,  r i v e r and  place  (1942) that the b r e e d i n g  lower  issue. while  Gangetic Some  others  system  authors  has  rejected  disagreed  in  for a the their  65 o p i n i o n as to the time of s p a w n i n g . their  collection  surmised  pre-  and  that H i l s a b r e e d s  systematic  larval  Research  thereby  p o s t - l a r v a e in the  conducted  during  the  i n d i c a t i n g the  Shafi  J o n e s and  by  the  years  et  ah  possibility  (1978)  and  Quddus  Menon (1951), b a s e d  Hooghly  system,  In a d d i t i o n , a Inland  1966  is v e r y  restricted  Chandra  (1962)  species.  The  of  size  gonad  abundance inferred  Fisheries  revealed  of  that  index, of  the  hatching  Indo-Bangladesh Hilsa  India, probably  date,  occur  region. breeding  based  spent  spent  at  the c o n t r a r y ,  a  that t h e  standstill  of  young  the  s t u d i e s on  the  estuary,  spawning  Hilsa  showed  sea is still  in the  of  on t h e  this study  ( F i g . 21)  the  and  existence  a controversial  (1963), sea  on  the the  the presence  present  study,  H i l s a in the habitat ( T a b l e 2) fish  breeding  during  Hooghly  winter  clearly  Pillay  In t h e  t h e r e , unless the  the  of  areas.  h e r o p i n i o n on  fish.  March,  reported  On  A g a i n , from  is no  availability  Whether H i l s a s p a w n s in the  m a t u r e and  (1984)  l a r v a e in the  there  w i n t e r b r e e d i n g in the B a n g l a d e s h  the  ah_  the  of t h i s s p e c i e s .  p r e s e n t f i n d i n g s in w i n t e r b r e e d i n g , b a s e d  back-calculations  reported  et  if not  fish  and  spawning  hauls, concluded  distribution  may  River  on  on s c a r c i t y of the p r e - a n d p o s t - l a r v a e  January.  r i p e and  and  in B a n g l a d e s h w a t e r s .  w i n t e r months of D e c e m b e r and  the  Central  1965  of w i n t e r  of t h e s p e c i e s in r o u t i n e p l a n k t o n the  Ganga  of p o s t - l a r v a e in t h e c o l l e c t i o n s d u r i n g the month of  e x i s t e n c e of w i n t e r b r e e d i n g  in  N a g p a l (1970), b a s e d  t h e r e in the w i n t e r s e a s o n .  survey  Institute  presence  Both  of  Ghos and  are m a k i n g  only  i s s u e in  author  Saurastra t h e r e of  coast  brief  that  trips  in  maturing,  the evidence  suggests  who  of  both  spawning  into  nearby  66  FIGURE 21.  Diagrammatic maturity growth  summary  (G.S.I.  seasonal  = Gonadosomatic  and movement  indicated  of  of y o u n g .  by t r i a n g l e s ,  by  lengths  from experimental  circles  a r e mean l e n g t h s  offshore; lines  horizontal  vertical  suggest  different  bars.  lines  boundaries  principal  of  of  Index),  Peak  extent  periods  timing  adult  hatching,  hatching  principal  Open c i r c l e s  are s i z e for  spawning  periods.  mean  solid catch  ranges.  offspring  hatching  are  seining inshore; from f i s h e r m e n ' s  times  from  Diagonal  67  TABLE 2.  Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent H i l s a i n marine h a b i t a t , c o l l e c t e d from C h i t t a g o n g i n 1983-1984.  Percentage of Composition Month of Sampli ng  Mature  October  75  21  4  24  December  88  0  12  25  January  46  0  54  24  February  67  0  33  24  March  4  0  96  25  April  0  0  100  25  May  20  0  80  25  June  84  4  12  25  July  0  68  32  25  24  68  8  25  August  Spent  Sample Size  Maturing  69 estuaries  or  rivers  to  release  their  eggs.  (Comparable  data  on  s p a w n i n g c o n d i t i o n f o r M e g h n a R i v e r and  e s t u a r i n e H i l s a a r e shown in  the  is  Appendix).  However,  a v a i l a b i l i t y of e g g s and  as  there  l a r v a e in the  as  yet  no  evidence  marine h a b i t a t , the  question  w h e t h e r s p a w n i n g a c t u a l l y o c c u r s t h e r e must remain open at D i f f e r e n c e in b r e e d i n g unusual  variation  Though  the  freshwater, to  breed  in  in  rivers  in T h a i l a n d  behaviour  European  Hilsa toli, which  and  of  this  American  (Smith type  1945).  has  shads  also  (genus  near  shallow  1961).  Lake  offshore  Gras  Nokone  banks  (1958) has  (Dahomy)  in  the  is not  b r e e d s in  It has  In  reported  breeds  in  been  yet to be  determined  whether  Hilsa  of  lake  or  other  that t h e r e  body depth. here,  suggest  tions  of  the  characteristics.  a r e two  races  H o w e v e r , o u r own that b o d y fish,  and  depth is not  racial indicator requires f u r t h e r  Quddus  separable  on  been  this  itself,  only in the at  in  found  of  sea.  different  distinctive  et^ a l . (1984) the  a  Leone  (lagoon)  s e a s o n s i n t h e M e g h n a R i v e r r e p r e s e n t d i f f e r e n t r a c e s with morphometric  breed  stock  spawning  as  observed.  Sierra  that t h e  the  shad  Alosa)  Sea  u n l i k e t h e marine s t o c k s , w h i c h are k n o w n to b r e e d  reported  present.  to s a l i n i t y  t h e West A f r i c a n s h a d , E t h m a l o s a d o r s a l i s , has  (Bainbridge shad  respect  of  t h e Indian coast ( C h a c k o - K r i s h n a m u r t h y 1949), is k n o w n to  in f r e s h w a t e r  group  with  among f i s h e s of t h e g e n u s H i l s a .  t h e sea on breed  behaviour  of  b a s i s of  have  relative  p r e l i m i n a r y i n v e s t i g a t i o n s , not r e p o r t e d v a r i e s c o n s i d e r a b l y with strictly study.  isometric,  so  sexual i t s use  condias  a  70 4.2  E a r l y g r o w t h and One the  h a t c h i n g date  of t h e major h a n d i c a p s in t h e s t u d y of H i l s a b i o l o g y has been  lack  of  a  suitable  method  f o r age  l i t e r a t u r e shows that many w o r k e r s , 1940), C h a c k o et a L (1953),  Pillay  They  the  results  addition,  but  the  Pillay  (1973) t r i e d polygons.  (1958),  method  often confounded selective  was  tried  by  the  first  suggested  have  use  r e a d i n g s of a n n u l i  has  not  extended  been Rao  reported  require  Nair  of  Hilsa  by  formation does not take spawning  (1962),  of H i l s a b y been  age  encouraging  so  and  marks  on  far.  In  Rajyalakshmi  using length-frequency  reliable b e c a u s e  h a t c h i n g p e r i o d s , and  of o t o l i t h s by  Shafi  in a g i n g  Hilsa  e_t a l . (1976) the  in otoliths.  age  According  but  that  that  the  hard  parts  results  confirmation.  temperate  rings and  in a few  have  not  However, even  r i n g s in otoliths may  growth  like  the a n a l y s i s is  sometimes b y  size  aging  be  fish  a  be  possible  in B a n g l a d e s h .  Later,  through  the  to them, t h e  annulus  was  R e c e n t l y , Raja and  otoliths  encouraging  in the  u s e f u l to age is  might  Hilsa  scales been  fish  of adult  in otoliths at t h e time of s p a w n i n g .  tried,  growth  not  t h e age  the  to i n t e r p r e t  and  Q u d d u s et a l . (1984) d e t e r m i n e d  India  of  sampling.  That  formed  to determine  also t r i e d  Pillay  to determine The  review  e s p e c i a l l y in India ( H o r a and  H o w e v e r , seasonal a n n u l u s  p l a c e in the s c a l e . scales,  A  (1948), Raj (1951), Jones and Menon (1951), Menon  (1958)), h a v e  t h e scale method.  determination.  absence fish.  or of  The  well-established  (1984) in have  been  that  they  annuli,  the  use of daily technique  t r o p i c a l a r e a s , but t h e p r e s e n t s t u d y  is the  in first  71 attempt  in the Indo-Bangladesh  Hilsa by using  region  first  ring  (Taubert  Wilson and  growth  deposition  age  age of j u v e n i l e  growth rings i n the otoliths.  C r e c c o ^ t a l . (1982) s u g g e s t e d the  to estimate  ring  was  that  deposited  in Connecticut  shortly  after  and Larkin  1982) , b y  rearing  1978, Neilson  wild  fish  larvae  hatching.  was v a l i d a t e d b y many a u t h o r s u s i n g  a n d C o b l e 1977, B a r k m a n  shad  Daily  l a r v a e of k n o w n a n d Geen 1982,  in enclosures  (Wilson  L a r k i n 1980) , o r b y t h e i n c o r p o r a t i o n of time m a r k e r s ( C a m p a n a a n d  N e i l s o n 1982, Neilson a n d Geen 1984). t i o n rate was assumed to be c o n s t a n t  In many c a s e s , t h e r i n g d e p o s i f o r the entire larval period  a wide r a n g e of e n v i r o n m e n t a l c o n d i t i o n s  (Geffen  1982).  over  Taubert and  C o b l e (1977) a n d Methot a n d K r a m e r (1979), h o w e v e r , r e p o r t e d that r i n g d e p o s i t i o n c e a s e d u n d e r s e v e r e c o n d i t i o n s of s t a r v a t i o n o r low temperature  but indicated  deposit  unsuccessful  age at  as  growth  continues,  larvae  will  tetracycline in the present  in Hilsa otoliths,  and  saline  study  immersion  experiments  to validate t h e daily  t h e agreement  were  formation  of t h e P e t e r s o n  method  of with  as d e t e r m i n e d b y g r o w t h r i n g s s u g g e s t e d that t h e r i n g s were formed t h e rate of one p e r d a y , a n d that t h e f i r s t r i n g may be formed j u s t  after  hatching. The  rings not  as long  one r i n g p e r d a y .  Although  rings  that  o t o l i t h s of t h e smaller  size  i n t h e whole o t o l i t h , b u t i n o l d e r  clearly  counting 4.9 cm.  v i s i b l e i n all a r e a s .  group  of H i l s a  showed  Hilsa the growth  T h e direct and indirect  rings  clear were  methods of  d i d not g i v e a n y s i g n i f i c a n t d i f f e r e n c e s i n size g r o u p s up to Therefore  in this  study,  although  it was  not p o s s i b l e to  extend that  d i r e c t c o u n t s to o l d e r size  age  determination  ( i n d i r e c t ) might be r i n g s , which  was  v a l u e s of 2.0  cm  in o l d e r  reliable.  size  The  by  were  old.  6 months  through  a g r e e with  increasing lished  MS)  f o r age  Hence,  (1979) who  that  be so  on  the  hatching  of  rings.  6 months o l d ) .  reported  that  These  growth  U c h i y a m a and  rings  Struhasker  r i n g s in whole mounted otoliths of s k i p progressively Campana  utility  determination  Information otolith  r i n g s and  it is s u g g e s t e d  days.  Recently,  p a r t i c u l a r l y in s p e c i e s f o u n d  tion  Growth rings could  (approximately  becomes  size.  reported  examination  30  age  tuna  specimen  H i l s a showed  o t o l i t h - g r o w t h r i n g s is p o s s i b l e i n o r d e r to  Brothers  yellowfin  method  age  (1981) r e p o r t e d that c o u n t i n g and  group  Ralston  l o n g , w h i c h showed 171  o f t e n become u n c l e a r a f t e r about 200  jack  size  the  assumed  that  H i l s a j u v e n i l e s up to about 12 cm findings  by  the P e t e r s o n method. cm  determination  cm  cm) , it was  the month-wise p r o g r e s s i o n of modal  c o u n t e d in j u v e n i l e H i l s a 12.0 approximately  (>5.0  groups  2.0  c o n s i s t e n t with found  groups  of  beyond  more  and  Neilson  otolith  one  year  difficult  with  (unpub-  microstructure is  questionable,  in temperate z o n e s . date c a n be d e t e r m i n e d from t h e examina-  Many  authors,  such  as  Ralston  (1976),  S t r u h a s k e r and U c h i y a m a (1976) , T o w n s e n d and Graham (1981) , S t e f f e n s e n (1980), and to  L o u g h et a l . (1982), have u s e d  determine the h a t c h i n g  hatching The three  date of f i s h e s .  time of j u v e n i l e H i l s a  observed  was  times  In the  determined  t r i m o d a l p e a k s in h a t c h i n g  major s p a w n i n g  the otolith  for Hilsa.  by  microstructure  present the  study,  same  method.  time i n d i c a t e that t h e r e  These  the  findings supported  are the  73 e v i d e n c e f o r t h r e e s p a w n i n g times of H i l s a i l i s h a in t h e M e g h n a R i v e r of B a n g l a d e s h  4.3  based  on gonad size i n d e x  ( F i g . 21).  M i g r a t o r y movements of j u v e n i l e s A  review  of l i t e r a t u r e  r e v e a l e d that much migratory The  on  migratory  movements  of H i l s a  ilisha  attention has been paid to m i g r a t i o n of a d u l t s , b u t  information  on  juvenile  Hilsa  is s c a n t y  and  conflicting.  m i g r a t o r y b e h a v i o u r of H i l s a d e s c r i b e d b y many w o r k e r s , has been  based  almost  entirely  on  catches  The  i n f o r m a t i o n on m i g r a t o r y  the  present  length  data  juvenile first  study  Hilsa  attempt  on  experimental  of fishermen's  in the different undertaken  commercial  fishing  movements of j u v e n i l e  a r e based  analysis  by  c a t c h , and  areas  specifically  gill  equipment.  Hilsa obtained in and  seine  collected  nets,  samples of  in B a n g l a d e s h .  This  to p r o v i d e a p i c t u r e  is the  of j u v e n i l e  Hilsa migration. Based  on t h e r e s u l t s of e x p e r i m e n t a l beach  was  observed  live  in t h e s h o r e  When  they  that  attain  juvenile and  shallow  larger  Based  g e a r c a t c h , ( F i g . 21) J a n u a r y in d e e p e r  migration January mean  river  areas  than  from  i n total in the  it  length river.  r i v e r , and  on l e n g t h data a n a l y s i s of fishermen's was t h e time of c o n g r e g a t i o n of j u v e n i l e  the river.  in A p r i l  from the r i v e r ( F i g . 21).  ( F i g . 21) ,  migrate to t h e d e e p e r  to t h e immigration  l e n g t h of 12.0 cm  8.0 cm  (<10 f t . d e p t h )  (>10 f t . d e p t h ) .  of t h e s e f i s h corresponded  less  size, they  sustain a fishery there.  Hilsa  Hilsa  seining  May A  was t h e month mean  l e n g t h of 7.0 cm in  size to t h e d e e p e r  corresponded  f o r total  river;  to t h e m i g r a t i o n  a  size  T h e total d i s a p p e a r a n c e of j u v e n i l e s i n May  74 f r o m the d e e p e r water i n t h e r i v e r M e g h n a of N o r t h  Chandpur  clearly  s u g g e s t e d t h e m i g r a t i o n of j u v e n i l e s from the r i v e r . These workers  findings  on  According  related  are  in  g e n e r a l agreement  species,  to Jones a n d  or  Menon  on  Hilsa  with  ilisha  (1951), e g g s and  those  in  by  other  other waters.  l a r v a e of H i l s a  ilisha  w e r e p r e s e n t in l a r g e r n u m b e r s near t h e bank t h a n i n t h e middle o r t h e r i v e r w h e r e t h e c u r r e n t was Hilsa  larvae  in different  stronger.  water  Regarding  zones,  Ghos  and  the d i s t r i b u t i o n of Nagpal  (1970)  con-  c l u d e d that t h e l a r v a e p r e f e r m a r g i n a l waters i n t h e r e g i o n s w h e r e t h e total d e p t h does  not e x c e e d  a p p r o x i m a t e l y 1.3  no l a r v a e o c c u r i n t h e d e e p e r l a y e r s . American  shad  r i v e r bottom. bottom and  Marcy  m  (4.3 f t . ) ;  (1976) noted that o v a of  ( A l o s a s a p i d i s s i m a ) a r e semi-buoyant Newly h a t c h e d A m e r i c a n  practically  and d r i f t along t h e  s h a d l a r v a e also remain near t h e  u n t i l t h e yolk is n e a r l y gone, a f t e r which t h e y swim near s h o r e  become s u s c e p t i b l e to seine s a m p l i n g . Concerning  Sujansinghani fishermen's  t h e timing of the f i s h e r y f o r j u v e n i l e  (1957)  catch  that  concluded juveniles  based are  on  length  generally  H i l s a , i n India  data  abundant  analysis in the  of cold  s e a s o n from N o v e m b e r to J a n u a r y ; t h e r e i s a m a r k e d d e c r e a s e i n n u m b e r s f r o m F e b r u a r y o n w a r d s , with p r a c t i c a l l y no y o u n g H i l s a i n t h e c a t c h e s towards the end  of M a r c h .  Rao  (1969) said  that i n t h e lower  reaches  of G o d a v a r i e s t u a r y i n India t h e j u v e n i l e f i s h e r y e x t e n d s from J a n u a r y to J u n e with a peak p e r i o d from F e b r u a r y to A p r i l .  He  t h a t most of the f i s h from the c a t c h e s r a n g e d from 9 cm only  a few  (1984)  are b i g g e r from  reported  that  16 cm  the J a t k a  to 19 cm.  (young  Hilsa)  In  also  reported  to 15 cm,  Bangladesh,  fishery  begins  and  Melvin around  75 January the  and  c o n t i n u e s u n t i l A p r i l when the f i s h  present s t u d y , based  observed  to be  r i v e r , and findings  on  e x p e r i m e n t a l gill  the time of a p p e a r a n c e  May  was  suddenly netting,  the  February  of j u v e n i l e H i l s a in the  the time of d i s a p p e a r a n c e from  corroborate  vanish.  observations  on  the r i v e r .  length  data  In was  deeper These  analysis  of  fishermen's gear d a t a d i s c u s s e d a b o v e . The migration  disappearance  of y o u n g  of the j u v e n i l e s .  Hilsa  Which  direction  e s s e n t i a l matter of t h e d i s c u s s i o n . that  conflicting  conclusions  o p i n i o n s were  were  based  on  from  A  river  they  indicated  migrate  becomes  review of the l i t e r a t u r e  expressed  the  the  by  analysis  of  many  an  showed  authors.  fishermen's  the  Their  catch.  In  f a v o u r of d o w n w a r d  m i g r a t i o n , H o r a (1938) b a s e d  on  young  Nowabganj  November-February,  specimen  at  in  India  during  the c o l l e c t i o n of  c o n c l u d e d that the y o u n g f i s h do not r e s i d e i n the r i v e r but p a s s down to  the  estuaries.  Sujansinghani  (1957)  said  that  there  is a  large-  scale d o w n w a r d movement of f i s h commencing about  January-February.  Pillay  as  (1958)  observed  that  m i g r a t e down t h e r i v e r s a n d  spent  Hilsa  concluded On  of  catches  of  fixed  t h e o t h e r h a n d , P a n d i t and  Ramakrishnaiah  purse  that l a r g e r j u v e n i l e s moved  nets  to H o r a and  their  progeny  that the coastal (1972) based  on  November-January  into f o r e s h o r e a r e a s .  H o r a (1951) b e l i e v e d that in M a r c h - A p r i l (Bangladesh)  form an i n d e p e n d e n t  N a i r (1940), t h e J a t k a c a u g h t  f i v e months o l d and  in  downward  t h e y o u n g , k n o w n as J a t k a , e n t e r E a s t B e n g a l l a r g e swarms f o r f e e d i n g and  well  the lower e s t u a r i e s , and  a r e a s form the habitat of the s p e c i e s . observation  as  a r e m i g r a t i n g up  from  fishery.  in East Bengal  waters in According rivers  are  the estuaries for feeding.  It  has,  however,  mature and  been  migrate  shown  Pillay _ejt a l . (1963) the  not  as  as  was  the  analysis  range  originally  Gangetic R i v e r system study,  Pillay  (1958)  u p r i v e r for spawning.  and  great  by  gilling  of migration of  b e l i e v e d , and  direction  these  fish  A c c o r d i n g to P i l l a y  of  Hilsa  the  d e p e n d on more t h a n one of  that  fish  (1952)  is p r o b a b l y  fisheries  stock.  are  of  the  In t h e p r e s e n t  i n the  experimental  g i l l n e t sampling in t h e M e g h n a R i v e r d u r i n g the p e r i o d  October-August,  and  of  the  recorded  i n f o r m a t i o n of  gradual  increments  mean  length  d o w n s t r e a m , s t r o n g l y s u p p o r t t h e e x i s t e n c e of a d o w n s t r e a m migration of  j u v e n i l e H i l s a in B a n g l a d e s h The  juvenile in  downstream Hilsa  South  first the  m i g r a t i o n is also s u p p o r t e d  in t h e  India  waters.  estuary  rivers,  Raj  and (1937)  y e a r of i t s life in t h e lower sea  in t h e  small-sized  third  the  year.  sea.  stated  reaches  Naidu  by  With that  r e f e r e n c e to  the  of t h e  (1939)  reported  south  Bazar  Cox's  (Bangladesh),  including the Hooghly (India). Hilsa  Prashad during and  9"-10"  long  along  jet a l . (1940) the f i r s t  year  and  that  the  Chittagong  that  the  in  N o v e m b e r was  reported by  is a v a i l a b l e  to  the  fish  Coast  coastal  areas  Raja  suggest  of  The in  (1984).  mouths  in  migrates  the  in  even  of  rivers  presence  Bangladesh. into  the  of  sea  the f o r e s h o r e Hilsa  October  the o t h e r h a n d , no  appearance  of  October-  a p p e a r a n c e of y o u n g  Bangladesh On  goes to  of B e n g a l ,  of i t s l i f e , w h e r e it moves along  does not go f a r out into t h e s e a . the  in  the  shoals  Mozumder (1939) r e f e r s to t h e  stated  (21-24.0 cm)  ture  and  Hilsa  spends  H i l s a of 9"~10" b e g i n to make t h e i r a p p e a r a n c e in y e a r along the f o r e s h o r e of the B a y  of  fish  rivers,  November e v e r y to  r e p o r t s of o l d e r  shoals  of  and  literayoung  77 H i l s a in the u p p e r a r e a s , e i t h e r in India o r in B a n g l a d e s h . seems f a i r l y c e r t a i n t h a t y o u n g H i l s a migrate The  downstream.  f a c t o r s t r i g g e r i n g t h e d o w n s t r e a m m i g r a t i o n of j u v e n i l e  a r e still u n k n o w n . temperatures rivers.  Only  might  the author  serve  to  Melvin (1984) s u r m i s e d  trigger  the  young  Hilsa  of  juveniles  the  emigration spawning  of  Whitney 1972) juvenile  Marcy  the  fastest The  shad  and  growing  and  Burgner  factor deeper  from  findings  hence  time  the  be  the  and  high  with  to  river  hypothesis may  falls  leaving the  to c h a n g e s  below  Leggett  15.5°C.  of j u v e n i l e  the  shad = the  river  swimming  with  of  first.  ability  serve  associated  flows d u r i n g  as  just  river  (1977) s t a t e d (1954)  an as  and  important it does in  length-dependent  juvenile factors,  of The  high  Foerster  in s h a d ,  of  the  Leggett  it is p o s s i b l e that a emigration  the  length-dependent,  associated  survival  other  of  of t h e marine m i g r a t i o n .  emigration  study,  that  linked  emigration  juveniles  is  the  r e g u l a t o r of  along  and  like  timing  d o w n s t r e a m migration  of t h e late a u t u m n .  is r e s p o n s i b l e f o r the river  The  partially  related  river  support  In t h e p r e s e n t  temperature  also  The  C h i t t e n d e n 1969,  temperature  of the  largest  may  (1962) that size  density-dependent salmon.  water  R i v e r was  low t e m p e r a t u r e s  these  rivers,  Lehman 1957,  to meet t h e r e q u i r e m e n t s  emigration  flows and  when  that the  length-dependence  final  the  occurs sequentially.  occurs  Connecticut  juvenile shad  that  ( S y k e s and  (1976) noted  from  from  m i g r a t i o n of t h e a d u l t s , is c l o s e l y  i n water t e m p e r a t u r e  of  leave  In c o n t r a s t , e x t e n s i v e work on t h e s u b j e c t has b e e n done by a A m e r i c a on j u v e n i l e A m e r i c a n s h a d .  and  Hilsa  that r i s i n g  to  many a u t h o r s in N o r t h  spring  H e n c e , it  Hilsa such  t h e monsoon.  from as  the  rising  It is notable  78 ( F i g . 21) that y o u n g h a t c h e d  from late monsoon s p a w n e r s remain i n t h e  r i v e r a n d grow l a r g e e n o u g h t h e r e to s u p p o r t during hatched  t h e low d i s c h a r g e  periods.  On  the other  hand,  young  from w i n t e r s p a w n e r s do not r e a c h a size l a r g e e n o u g h to move  offshore until after fishery,  winter  an o f f s h o r e J a t k a f i s h e r y  a n d may  t h e monsoon f l o o d s b e g i n ;  in fact  t h a t of t h e i r late monsoon  be swept  downstream  counterparts.  they  support  no  at a smaller size  Jatka than  79  LITERATURE CITED Bainbridge,  V.  1961.  T h e early  life  dorsalis (Cuvier and Valenciennes).  history  of t h e B o n g a ,  Ethmalosa  J . de C o n s e i l . 26:347-353.  B a r k m a n , R . C . 1978. T h e u s e of otolith g r o w t h r i n g s to a g e y o u n g s i l v e r s i d e s , Menidia Brothers,  E.B.  menidia.  1979.  Age  Trans. and  In S.B. S a i l a a n d P.M. Loedel small-scale  fisheries,  Am. F i s h . S o c . 107:790-792.  growth  studies  ( e d s . ) , Stock  p . 119-236.  Atlantic  on  tropical  fish.  assessment  for tropical  International Centre  f o r Marine  R e s o u r c e s D e v e l o p m e n t , U.R.I. B h a n o t , K.K. the  1973. O b s e r v a t i o n s  Hooghly estuary.  B u r g n e r , R.L. Alaska, Univ.  J . Inland F i s h . S o c . India 5:50-54.  1962. S t u d i e s  pp.28-314.  of r e d salmon  smolts  from  t h e Wood  Lakes,  ln_ T . S . Koo ( e d . ) , S t u d i e s of A l a s k a R e d Salmon,  Wash. P u b l . F i s h . , W.S.I.  Campana, S.E. and J.D. Neilson. of  on t h e s p a w n i n g of H i l s a i l i s h a (Ham.) i n  starry  flounder  environmental  1982. D a i l y g r o w t h i n c r e m e n t s  ( P l a t i c h t h y s stellatus)  variables i n their  i n otoliths  a n d t h e i n f l u e n c e of some  production.  Can. J . Fish.  Aquat.  S c i . 39(7):937-942. Campana,  S.E.  growth  increments  gairdneri) Can.  1983.  and  Feeding in  the  starry  periodicity otoliths  and the production of  flounder  steelhead (Platicthys  trout  of d a i l y (Salmo  stellatus).  J . Z o o l . 61:1591-1592.  Campana, S.E. and J.D. Neilson. otoliths.  1985.  MS.  Incremental  growth  of f i s h  80 C h a c k o , P.I., A . R . K . Z o b a i r i , a n d B. s c a l e s of H i l s a i l i s h a Sci. Chacko,  Krishnamurthy.  (Ham.) as an  index  1948.  The  and  age.  of g r o w t h  radii of Curr.  17(5):158-159. P.I.  and  B.  ( B l e e k e r ) and C h a n d r a , R.  Krishnamurthy.  1949.  H i l s a toli ( C u v . a n d V a l . ) .  1962.  M.E.,  Shad,  Alosa  jr.  and  with  Hilsa  Life  history the  L. G u n n .  American  changes  in  Shad  S c i . a n d C u l t . 15:118-119.  in year  and  ecology  Delaware  class  abundance  of t h e  River.  American  Ph.D.  thesis.  45pp.  1983.  (Alosa  kanaqurta  Indian J . F i s h . 9:48-70.  Brunswick, N.J.  T. Savoy, and  juvenile  River  1969.  sapidissima,  R u t g e r s U n i v . , New C r e c c o , V.,  on  A p r e l i m i n a r y a c c o u n t of t h e d i s t r i b u t i o n a n d  of f i s h l a r v a e i n t h e H o o g h l y e s t u a r y . Chittenden,  Notes  D a i l y mortality r a t e s of l a r v a l  sapidissima)  strength.  in the  Can.  Connecticut  J . Fish.  Aquat.  S c i . 40:1719-1728. Day,  R.  1873.  Burma. De,  D.K.  Calcutta,  1980.  Hilsa,  Hilsa  estuary Foerster,  R e p o r t on  the freshwater  ilisha  R.E.  (Ham.)  Can.  Geffen, A . J . herring Mar.  and  in the  f i s h e r i e s of India  and  spawning upper  of post-monsoon  stretches  of  the  r u n of  Hooghly  J . Inland F i s h . Soc. 1 2 ( l ) : 5 4 - 6 3 .  1954.  On  ( Q . n e r k a ) r e t u r n to k n o w n Board  and  pp 22-23; 35-36.  Maturity, fecundity  system.  fish  the  relation  of  smolt seaward  adult  sockeye  migration.  salmon  J . Fish.  Res.  11:339-350.  1982.  Otolith  ring  deposition  ( C l u p e a harenqus) and  B i o l . 71:317-326.  turbot  i n relation  to g r o w t h  rate i n  ( S c o p t h a l m u s maximus)  larvae.  Ghos, A.N., and T.D. Nagpal. (Ham.) Counc. G r a s , R.  in the Ganga  1970. On t h e w i n t e r b r e e d i n g of H i l s a i l i s h a  River  system.  Proc.  Indo-Pacific  Fish.  13(2):132-142. 1958.  Notes  T h e fishing  and  of Ethmalosa d o r s a l i s  documentation  on  fishing  in the Lake and  Nokone.  fish  culture.  C . T . F . T . 4:1-11. H o r a , S . L . a n d K.K. N a i r .  1940. F u r t h e r o b s e r v a t i o n o n t h e bionomics a n d  f i s h e r y of t h e Indian s h a d H i l s a i l i s h a (Ham.) i n B e n g a l w a t e r s . R e c . Indian  Mus. 4 2 ( l ) : 3 5 - 5 0 .  H o r a , S . L . 1938. A p r e l i m i n a r y note o n t h e s p a w n i n g g r o u n d s a n d bionomics of t h e s o - c a l l e d R e c . Indian  Indian  shad, Hilsa ilisha  Soc. Job,  of  Ganges.  Mus. 40(2)-.147-148.  Islam, B . N . a n d C . B . T a l b o t . dity  (Ham.) i n t h e r i v e r  Indus  River  1968. F l u v i a l m i g r a t i o n , s p a w n i n g a n d f e c u n Hilsa,  Hilsa  ilisha.  Trans.  in Bengal  waters.  Am.  Fish  97(4):350-355.  T.J.  1942.  Hilsa  investigation  Sci.  and  C u l t . 7(9) :427-429. J o n e s , S. a n d P.M.G. Menon. Hooghly River.  1950. S p a w n i n g  S c i . and Cult.  J o n e s , S. a n d P.M.G. Menon. Indian  shad,  Hilsa  of Hilsa i l i s h a (Ham.) i n t h e  15(11) :443-444.  1951. O b s e r v a t i o n  ilisha  (Ham.).  on t h e life h i s t o r y of t h e  Proc.  Indian  Acad. S c i .  31(3):101-125. Karamchandani,  S . J . 1961. On t h e location of s p a w n i n g  s h a d , Hilsa ilisha Curr.  (Ham.) i n f r e s h w a t e r  S c i . 30(10) :373-375.  g r o u n d s of Indian  r e g i o n s of t h e N a r b a d a  River.  82 Kulkarni,  C.V.  Indian  1950.  shad  Breeding  Hilsa ilisha  habits,  (Ham.) in  eggs  the  and  early  Narbada  life  River.  history Proc.  of  Nat.  I n s t . S c i . India 16(3) :169-176. L e g g e t t , W.C.  and  of A m e r i c a n Leggett,  R.R. shad.  W.C.  C.C.  M. of  M a r c y , B.C.,  Atlantic  1976.  Connecticut  River  141-168.  American  shad  H i l s a F i s h e r i e s of B a n g l a d e s h .  (Alosa  A  report  21pp.  B o l z , and  b a s e d on  F i s h . Soc.  Am.  P.K.  1964.  and  J_n_  plant.  Melvin,  of  A.  Rosenberg.  Clupea  harenqus  1982. in  the  Age  and  Gulf  of  otolith g r o w t h i n c r e m e n t s .  E a r l y life h i s t o r y s t u d i e s of A m e r i c a n  River  J.  rates  Fish.  80:187-200.  jr.  p.  migration  C a n a d a 34:1422-1426.  herring,  region  Connecticut  Mathur,  Board  P e n n i n g t o n , G.R.  U.S.  plant.  migration  R e p o r t on  larval  the  F i s h Wildl. S e r v . F i s h . B u l l . 70:659-670.  J . F i s h . Res.  Main, Georges Bank  lower  Water t e m p e r a t u r e and  f o r I.D.R.C., C a n a d a .  L o u g h , R.G.,  Bull.,  1972.  Ocean  1981.  prepared  growth  U.S.  1977.  sapidissima). Lindsey,  Whitney.  D.  the  e f f e c t s of  Merriman  ecological s t u d y :  and  the  the  shad  Connecticut  L.M.  Thorpe  impact  of  a  in  the  Yankee  (ed.) ,  nuclear  The  power  M o n g o r . I. 252pp.  Maturity  and  fecundity  of  Hilsa  ilisha.  Indian  Fish ll(l):423-449. G.D.  report  1984.  I n v e s t i g a t i o n of the  prepared  processing Document  and 5.  for  the  Fisheries  appraisal project.  FAO,  Hilsa Fishery Advisory Rome.  of B a n g l a d e s h . Service,  A  Planning,  FI:DP/BGD/81 034  Field  83 Menon,  M.D.  tropical Soc.  1953. and  T h e determination  subtropical  of age a n d g r o w t h  waters.  J.  Bombay  of f i s h e s of Nat.  Hist.  51(3):623-635.  Methot, R.D., j r . a n d D. K r a m e r .  1979. G r o w t h  E n q r a u l i s mordax, larvae in the sea.  of n o r t h e r n  anchovy,  F i s h . B u l l . , U.S. 77:413-423.  M o z u m d a r , C . H . 1939. F o r e s h o r e f i s h i n g in t h e e a s t e r n p a r t of t h e B a y of Bengal. Motwani,  S c i . a n d C u l t . 5(4):219.  M.P. , V . P . J h i n g r a n ,  breeding Sci.  of t h e Indian  and S.J. Karamchandani.  shad, Hilsa ilisha  d e t e r m i n a t i o n of a g e a n d g r o w t h  in the freshwaters.  1976. P r o b l e m s c o n c e r n i n g t h e  of H i l s a i l i s h a  (Hamilton  Buchanan).  B a n g l a d e s h S c i . C o n f . D h a k a A b s t . B , 43.  M. S h a f i , M.M.A. Q u d d u s , a n d M.N. Islam. Hilsa ilisha in the r i v e r Meghna. Naidu,  the  a n d C u l t . 23:47-48.  M. S h a f i , M.M.A. Q u d d u s , a n d H. Mokammel.  1st  (Ham.)  1957. O n  M.R.  1939.  Report  1978. M a t u r a t i o n a n d s p a w n i n g of  Dhaka Univ. Stud.  on a s u r v e y  26:63-71.  of t h e f i s h e r i e s  of B e n g a l .  Calcutta Govt. Press. N a i r , K.K. 1939. O n some e a r l y s t a g e s i n t h e d e v e l o p m e n t of t h e s o - c a l l e d Indian s h a d , Hilsa ilisha N a i r , P.V. Phillip.  (Ham.).  1958. S e a s o n a l c h a n g e s  in t h e gonads  of H i l s a i l i s h a  (Ham.)  J . S c i . 87(3):255-276.  N e i l s o n , J . D . a n d G.H. G e e n . microstructure examination. Neilson,  R e c . Indian Mus. 41(4) :409-418.  J . D . a n d G.H.  (Oncorhynchus  1981. Method  of otolith  Prog. Fish. Cult.  Geen.  tshawyt scha):  1982. daily  43:90-91.  Otoliths  growth  preparation for  of C h i n o o k  increments  salmon  and factors  84 influencing  their  production.  Can.  J.  Fish.  Aquat.  . S c i . 39:1340-1347. Neilson,  J.D.  1984.  potential  for assessing  (Oncorhynchus Univ.  Formation  of o t o l i t h - g r o w t h  the early  tshawytscha).  life  history  Ph.D.  of  and  their  chinook  salmon  Simon  Fraser  thesis.  145pp.  N e i l s o n , J . D . a n d G.H.  Geen.  1984.  E f f e c t s of f e e d i n g  t e m p e r a t u r e c y c l e s on otolith i n c r e m e n t salmon  (Oncorhynchus tshawytscha).  Pandit, C.G. and S.L. Hora. ilisha  increments  1951.  (Ham.) i n m a i n t a i n i n g  formation  in juvenile  F i s h . B u l l . , U.S.  T h e probable  Cholera  regimes a n d diel chinook  In p r e s s .  role of H i l s a f i s h ,  endemicity  in India.  Hilsa  Indian J .  Med. S o c . 5(7):343-356. Pannella,  G.  1971.  patterns.  Science  Pillay, T.V.R. of  Fish  otoliths:  daily  growth  patterns  and  173:1124-1127.  1952. A p r e l i m i n a r y biometric s t u d y of c e r t a i n  hilsa,  periodical  Hilsa  ilisha  (Ham.).  Proc.  populations  Indo-Pacific  Fish.  C o u n c . 4(2):181-194. Pillay,  T.V.R.  1958.  r i v e r Hooghly. Pillay,  T.V.R.  hilsa, Synopsis  Biology  a n d H.J.R. R o s a .  Hilsa  Hilsa  (Ham.)  of t h e  Indian J . F i s h . 5:201-257.  ilisha  1963.  Synopsis  (Ham.)  1822.  1962.  Observation  of b i o l g i c a l data  FAO  Fisheries  on  Biology  25(1) : l - 6 .  P i l l a y , S.R. a n d K.V. Rao. of  of t h e h i l s a , H i l s a i l i s h a  ilisha  (Ham.)  C o u n c . 10(2):37-61.  of R i v e r  Godavari.  on t h e b i o l o g y a n d f i s h e r y Proc.  Indo-Pacific  Fish.  Pillay,  S.R.  ilisha  1963. MS.  Maturation and spawning  migration  of  the so-called  1940. O b s e r v a t i o n s o n t h e s e a w a r d  Indian  shad,  Hilsa  ilisha  (Ham.).  I n d i a n Mus. 42(4) :529-552.  Q u d d u s , M.M.A., M. S h i m i z u , and Y . Nose. two  Hilsa  (Hamilton) of t h e S a u r a s t r a c o a s t .  P r a s h a d , B . , S.L. H o r a , a n d K.K. N a i r .  Rec.  of t h e H i l s a ,  1984a.  t y p e s of H i l s a i l i s h a i n B a n g l a d e s h  S p a w n i n g and f e c u n d i t y of  waters.  B u l l . Jap.  Soc. S c i .  F i s h 50(2):177-181. Q u d d u s , M.M.A., M. S h i m i z u , and Y . Nose. differences  between  1984b.  two t y p e s of H i l s a  B u l l . J a p . Soc. S c i . F i s h .  Meristic and  ilisha  morphometric  in Bangladesh  waters.  50(1)-.43-49.  Q u d d u s , M.M.A., M. S h i m i z u , a n d Y . Nose.  1984c.  g r o w t h of two t y p e s of H i l s a i l i s h a i n B a n g l a d e s h  Comparison waters.  of age Bull.  and  Jap.  S o c . S c i . F i s h . 50(1) -.51-57. Radtke,  R.L.  a n d J.M.  Dean.  1982. Increment  formation i n t h e otoliths of  e m b r y o s , l a r v a e a n d j u v e n i l e s of the mummichog, F u n d u l u s  heteroclitus.  F i s h . B u l l . , U.S. 80:201-216. Raj,  B.S.  1937. M a d r a s F i s h e r i e s  Department  Administrative  Reports for  1935-36. 1 9 p p . Raj,  B.S.  1951. A r e scales an i n d e x to t h e a g e a n d g r o w t h of t h e Hilsa?  P r o c . Nat. Raja, B.T.A.  I n s t . S c i . India 17(1) : l - 6 1984. C u r r e n t k n o w l e d g e on the b i o l o g y a n d f i s h e r y of H i l s a  s h a d , H i l s a i l i s h a (Ham.-Buch) of u p p e r B a y of B e n g a l . of  R e p o r t of B a y  Bengal Prog. 19pp.  Rajyalakshmi,  T.  1973.  T h e population characteristics  H i l s a o v e r the y e a r s 1963-1967.  of t h e G o d a v a r i  Indian J . F i s h . 2 0 ( l ) : 7 8 - 9 4 .  86 R a m a k r i s h n a i a h , M.  1972.  with an a c c o u n t Rao,  M.B.  on i t s racial s t a t u s .  1969.  Some  (Pisces: Clupeidae) Soc. Ralston,  B i o l o g y of H i l s a i l i s h a  observations  from  Godavari  (Ham.) from C h i l k a L a k e  Indian J . F i s h . 19:35-53. on  t h e j u v e n i l e s of  estuary.  Hilsa  ilisha  Nat.  Hist.  butterfly  fish  J . Bombay  66(1):116-131. S.  1976.  utilizing  Age  daily  determination  growth  rings  of t r o p i c a l of  reef  otoliths.  Fish.  Bull.,  U.S. 74:990-994. R a l s t o n , S. a n d G.T. Miyamoto. increments  to age t h e Hawaiian  Fish. Bull., Ricker,  1950.  Pristipomoides  filamentosus.  Cycle  dominance  among  the  Fraser  sockeye.  31:1-28.  S m i t h , H.M.  1945.  Mus. B u l l .  T h e freshwater  f i s h e s of Siam  (Thailand).  U.S. N a t .  188pp.  Steffensen, E.  1980.  Daily growth  J u v e n i l e East B a l t i c C o d . Struhasker,  Snapper,  U.S. 81:523-535.  W.E.  Ecology  1983. A n a l y z i n g t h e width of d a i l y otolith  indicated  purpureus by  observed  in otoliths  from  D a n a 1:29-37.  P. a n d J . H . U c h i y a m a .  Stolepphorous  increments  1976.  A g e and growth  (Engraulidae),  daily  growth  from  Hawaiian  increments  of  of t h e n e h u , islands  as  sagittae.  F i s h . B u l l . 74:9-17. Sujansinghani,  K.H.  1957.  G r o w t h of t h e Indian s h a d , H i l s a i l i s h a  i n t h e t i d a l s t r e t c h of t h e H o o g h l y . S y k e s , J . E . a n d B . A . Lehman. fishery Serv.  and  Indian J . F i s h . 4(2) :315-335.  1957. Past a n d p r e s e n t Delaware R i v e r s h a d  and considerations f o r i t s f u t u r e .  R e s . R e p . 46.  (Ham.)  25pp.  U.S.  Fish.  Wildl.  87 T a u b e r t , B.D. species Canada  and  of  D.W.  Coble.  Lepomis  and  1977.  Tilapia  mosambica.  Atlantic  and J . J . Graham.  Herring,  1981.  Clupea harenqus  e s t u a r y , Maine, as d e t e r m i n e d b y F i s h . B u l l . , U.S.  Fish.  Res.  Board  Katsuwonus indicated  by  Growth and age s t r u c t u r e of l a r v a l h a r e n q u s , in t h e S h e e p c o s t  daily  growth  River  increments in otoliths.  79(1):123-130.  U c h i y a m a , J . H . a n d P. S t r u h a s k e r .  Wilson,  J.  34:332-340.  T o w n s e n d , D.W.  U.S.  Daily i n c r e m e n t s i n otoliths of t h r e e  pelamis,  and  daily  growth  1981.  A g e a n d g r o w t h of S k i p j a c k t u n a ,  Yellowfin  tuna,  increments  Thunnus  of  sagittae.  albacores, Fish.  as  Bull.,  79:151-162.  K.H.  and  P.A.  o t o l i t h s of j u v e n i l e  Larkin.  1980.  Daily  s o c k e y e salmon  growth  increments in the  (Oncorhynchus  nerka).  Can.  J.  F i s h . A q u a t . S c i . 37:1495-1498. Wilson, K.H. daily  and  growth  sockeye  P.A.  Larkin.  1982.  Relationship  i n c r e m e n t s i n sagittae  salmon  (Oncorhynchus  S c i . 39:1335-1339.  and  nerka)  between  change  fry.  t h i c k n e s s of  in body  Can.  weight  J. Fish.  of  Aquat.  88 APPENDIX  APPENDIX TABLE 1.  Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent Hi 1sa i n e s t u a r i n e , c o l l e c t e d from B a r i s a l  in  1983-1984.  Percentage of Composition Month of  Sampli ng  Maturing  December  96.0  4.0  January  32.0  0  February  82.6  March  Mature  Spent  Sample Size  0  25  68.0  22  13.0  4.4  23  48.0  52.0  0  25  April  87.5  12.5  0  24  May  50.0  50.0  0  25  June  52.0  48.0  0  25  July  36.4 '  63.6  0  22  August  24.0  76.0  0  25  APPENDIX TABLE 2 .  Percentage c o m p o s i t i o n of m a t u r i n g , mature and spent Hi 1sa i n Meghna R i v e r , c o l l e c t e d from Chandpur i n 1983-1984.  Percentage of Composition Month of Sampli ng  Maturi ng  Mature  Spent  Sample Size  October  30.3  69.7  0  33  November  48.0  52.0  0  25  December  100.0  0  0  26  January  80.0  20.0  0  50  February  42.5  57.4  0  47  March  64.0  36.0  0  50  April  86.0  14.0  0  49  May  72.9  27.1  0  48  June  56.0  44.0  0  50  July  36.2  63.8  0  47  August  27.4  72.5  0  51  

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