00000nam 2200000za 4500 9.805741 CaOODSP 20221107135726 cr ||||||||||| 150406s2000 oncdb ob f000 0 eng d CaOODSP eng eng fre n-cn--- Fs70-1/2000-022E-PDF Success and failure of Atlantic cod, Gadus morhua [electronic resource] : a case study from coastal Newfoundland / I.R. Bradbury … [et al.]. Ottawa : Fisheries and Oceans Canada, 2000. 19 p. : fig., graphs, maps. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/022 Includes bibliographical references (p. 11-14). Despite a century of study, ecologists still struggle to understand fluctuations in marine populations, including many commercial species whose fisheries have collapsed despite considerable management effort. Data is presented on northwest Atlantic cod that encompasses the adult spawning to juvenile settlement stage and demonstrate that timing of spawning is critical, particularly as it relates to spawning location and coastal circulation in regulating recruitment success. In what is presently the largest commercially-exploited Atlantic cod stock remaining in the northwest Atlantic, it was found that spawning occurred at consistent, discrete locations that were generally favorable for propagule retention within the bay. However, when cod spawned relatively early in the year, colder water led to slower development, and currents swept most eggs offshore before hatch. Spawning later in the year resulted in faster hatching, thereby reducing duration of early and vulnerable life stages and the probability of being swept offshore. Elevated densities of pelagic larvae and settled juveniles were associated with late spawning. Successful recruitment to the coastal region therefore requires spawning at sites where propagules are likely to be retained, and at times when egg development rates are maximized. This 'right time, right place hypothesis' suggest that in tandem with more traditional variables such as spawner biomass and condition, timing and location of spawning may be important to spawning success in marine populations that live in highly seasonal environments. gccst Fisheries resources gccst Salt water fish gccst Fishing area gccst Fisheries management Bradbury, I. R. (Ian Robert), 1974- Canada. Department of Fisheries and Oceans. Canada. Canadian Stock Assessment Secretariat. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/022 (CaOODSP)9.507740 PDF 349 KB https://publications.gc.ca/collections/collection_2015/mpo-dfo/Fs70-1-2000-022-eng.pdf