Fee ndity of A antic C d (Gadus morhua) in he S ut estern .Gulf of S ...

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Table 2. Equations of size-fecundity relationships based on data from this study and from Powles (1957). Weights used In equations 5, 6 were derived from length-weight data from a 1959 research vessel cruise (W ; 0.0155 L2.9106) -5- SE of SE of Source Equation a b B est. R -----------_.- i , Buzeta and Haiwood (this study) F aLb 1.10 3.28 0.10 0.16 0.81 2. F b al~ 109.65 1. 14 0.09 0.14 0.86 3. F bH + a -516888 520 54.51 868194 0.77 4. Powles (1957) F aLb 0.38 3.50 0.24 0.17 0.83 5. F aW b 56.62 1.20 0.08 0.17 0.83 6. F bW + a -289333 415 22 .49 812803 0.89 7. 1957, ( this study) F aLb 0.68 3.38 0.19 D.17 D.82 Ii • II b\~ + a -2L,5579 425 21.13 0.02 O.1l5 _._----_.,-------"._--- N 30 43 n Oosthuizen and Daan (I 97 L, ) calculated fecundity of cod from Norway, Iceland, Labrador, and the North Sea, ba sed on the da ta of Bot ros (1962, si ted in May I 9b 7), Joaki Olsson (1969), Nay (1967), and Oosthui zen and Daa n (1974), r e s pe c t Lvel.y, From this study and that of Powles (1957), Gulf of St. Lawrence cod a npe a r to have lower fecundity than all other areas except La b r ad o r (Fig. 5; all lines based on equations given in Oosthuizen and Daan 1974). Interstock variability in fecundity has not been adequately explained and, without a critical evaluation of the various methods used, comparisons between studies should be made with caution. Notwithstanding this, it has been suggested that fecundity is influenced by environmental factors, such as water temperature, which may indirectly al ter the development of oocytes (Hodder 1965). Scott (1962) demonstrated that restricted ration and starvation in rainbow trout, Salmo gairdneri, resulted in a lowered maturation rate and follicular a tresia. Though follic ular atresia has not been demonstrated in cod, IJoodhead and Hoodhead (1965) suggested a mechanism whereby food availability in the summer, prior to spawning, could affect fecundity the following spring. If this mechanism operated, fishing effort could affect fecundity indirectly by changing population density and hence intraspecific competition for food. The remarkable similarity in the fec undity-Ieng th relationships between this and Powles' (1957) study suggests that either growth rates and/or environmental factors were not greatly different in the two periods, or the effect of growth on fecundity is relatively small when compared to genetically determined factors. However, further studies over several years must be undertaken in order to evaluate year-to-year variation in fecundity. ACKNOWLEDGNENTS h'e are indebted to the North Shore fishermen and L'Association Professionnelle des P6cheurs du Nord-Est Inc. for providing us with the biological material and to Hr , L. Lanteigne who coordinated the collections. Hr. I. Flemming assisted in the laboratory analysis and Hr. F. Cunningham, Ns. B. Fawkes and Ms. J. Hurley aided in the manusc ript preparation; Dr. J. S. Scott, Hr. D. Haldron, and Hs , R. Garnett prov Lded many valuable suggestions for
Nartin, H. R., and Y. Jean. 1964. Hinter cod taggings off Cape Breton and offshore Nova Scotia banks 1959-62. J. Fish. Res. Board Can. 21: 215-238. -6- Nay, A. H. 1967. Fecundity of Atlantic cod. J. Fish. Res. Board Can. 24: 1531-1551. NcCracken, F. D. 1959. Cod tagging off northern New Brunswick in 1955 and 1956. Fish. Res. Board Can. Pr og , Rep. At L, Coast. Sta , 72: 8-19. Oosthuizen, E., and N. man. 1974. Egg fecundity and maturity of North Sea cod, .Q.ad~ morhua , Ne t h . J. Sea Res. 8: 378-397. Pitt, T. K. 1964. Fecundity of hllPrican plaice, Hippoglossoides platessoides (Fabr.) from Grand Bank and Newfoundland areas. J. Fish. Res. Board Can. 21: 597-612. Powles, P. N. 1957. Studies of feeding and r e p rod uc t to n of cod (Gadus ca Lla r t a s L.) in the southwestern Gulf of St. Lawr.;;nc~N.Sc. Thesis. Universi ty of \4estern Ontario, london, On t , , 66 p. 1958. Studie s of reprod uc tio n and feed ing of Atlantic cod (Gadus callarias L.) in the southwestern Gulf-ofSt. Lawrence. J. Fish. Res. Board Can. 15: 1383-1402. Scott, D. P. 1962. Effect of food quantity on fecundity of r a Lnb o w trout Salm':!. ga Lrdne r i , J. Fish. Res. Board Can. 19: 715-736. Simpson, A. C. 1951. The fecundity of the plaice. Nin. Agric. Fish. Invest. Ser. 11, 17(5): 1-27 . Sivertsen, E. 1935. To r vk en s gytning Ned sxr1ing hendblikk Pa den arbige cyplus i generas j onsorganenes til stand. Fiskeridir Sk r , Ser , Ha vunde r s , IV, 29 p. Sorokin,V. P. 1961. The oogenesis and reproduction cycle of the cod (Gadus morhua Linn.). Trudy Pinro 10: 125-14"4-.------ Hoodhead, A. D., and P. N. J. Hoodhead. 1965. Seasonal changes in the physiolog y of the Barents Sea cod, Gadus morhua L., in relation to its environment":"""Int. Comm , Northw. At I , Fish. Spec. Publ. 6: 691-715.
Page 1 and 2: Fee ndity of A antic C d (Gadus mor
Page 3 and 4: Canadian Technical Report of Fisher
Page 5 and 6: i co r po dc iii ABSTRACT Iluzeta,
Page 7 and 8: Number of Blendinq Cycles 21 41 Fig
Page 9: 48 for the present study) were used

Fee ndity of A antic C d (Gadus morhua) in he S ut estern .Gulf of S ...

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