Systematic bias in estimates of reproductive potential of cod stocks: implications for stock/recruit theory and management. ...

• Main Authors: Marshall, C. Tara, Needle, Coby L., Thorsen, Anders, Kjesbu, Olav Sigurd, Yaragina, Nathalia A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ASC 2005 - Q - Theme session 2024
• Subjects: Fisheries and aquaculture; Technologies and data; Arctic cod; Arctic; Northeast Arctic cod
• Online Access: https://dx.doi.org/10.17895/ices.pub.25350409; https://ices-library.figshare.com/articles/conference_contribution/Systematic_bias_in_estimates_of_reproductive_potential_of_cod_stocks_implications_for_stock_recruit_theory_and_management_/25350409

No abstracts are to be cited without prior reference to the author.Stock/recruit relationships, describing the relationship between the parental population and the number of offspring produced, are a central tool in population ecology. For fish populations the stock/recruit relationship uses spawning stock biomass (SSB) to represent reproductive potential of the parental population. This assumes that the proportion of SSB comprised of females and the relative fecundity (number of eggs produced per unit mass) are both constant over time. To test these two constancy assumptions female-only spawner biomass (FSB) and total egg production (TEP) were estimated for the Northeast Arctic cod stock over a 56-year time period (1946-2001). During that time period the proportion of females (FSB/SSB) varied between 24 and 68% and the variation was systematic with length such that SSB became more female-biased as the mean length of spawners increased and more male-biased as mean length decreased. Over the same time period, ...