00000nam 2200000za 4500 9.826067 CaOODSP 20221107144512 cr ||||||||||| 170110s2016 oncbd ob f000 0 eng d 978-0-660-06591-5 CaOODSP eng eng fre n-cn-ns Fs97-6/3182E-PDF Óskarsson, G. J. (Guðmundur Jóhann), 1978- Fecundity and reproductive potential of Scotia-Fundy summer- and autumn-spawning herring (Clupea harengus L.) [electronic resource] / G.J. Óskarsson, C.T. Taggart and R.L. Stephenson. Title at head of French abstract: Fécondité et potentiel reproducteur des fraies d'été et d'automne du hareng (Clupea harengus L.) [Ottawa] : Fisheries and Oceans Canada, c2016. vii, 27 p. : ill., maps Canadian technical report of fisheries and aquatic sciences, 1488-5379 ; 3182 Cover title. Includes bibliographical references (p. 11-14). "Total egg production (E) by a fish stock, estimated using fecundity relationships, has been postulated to provide a superior estimate of a stock’s reproductive potential relative to the spawning stock biomass (SSB) estimate. We examined variation in the fecundity of Scotia-Fundy Atlantic herring using ovaries from 100 fully mature individuals collected on German Bank, NW Scotian Shelf, in September 2001 and in relation to historical fecundity estimates. Potential fecundity (FP; number of vitellogenic oocytes in mature ovaries) was a linear function of total length (r2=0.89). Length-specific FP was weakly (r2=0.10) and positively related to Fulton’s body condition index (K) and relative fecundity (eggs per unit somatic weight) was a positive linear function of total length (r2=0.61). The length-specific fecundity estimates in 2001 were higher than estimates recorded during the late 1960s and mid 1970s and the difference is not adequately explained by K or other factors. Decreases in length-at-age, age- and length-at-maturity and total egg production, particularly contributions from the larger (older) spawners, were observed over the period 1970-2001 and are consistent with changes that could be induced through size-selective fishing practices that target larger (faster growing and late maturing) individuals. The relationship between annual estimates of E and SSB for the stock over the same period approached proportionality with both recruit and repeat spawners indicating that reproductive potential may be adequately estimated from SSB. Partitioning the reproductive potential between recruit and repeat spawners or among different age or length classes may prove to be essential when determining the recruitment potential of the stock"--Abstract, p. v. Includes abstract in French. gccst Fisheries resources gccst Salt water fish gccst Fishing area gccst Fisheries management Taggart, Christopher Thomas, 1951- Stephenson, Robert (Robert L.) Canada. Department of Fisheries and Oceans. Canadian technical report of fisheries and aquatic sciences, 1488-5379 ; 3182 (CaOODSP)9.504449 PDF 436 KB https://publications.gc.ca/collections/collection_2017/mpo-dfo/Fs97-6-3182-eng.pdf