00000nam 2200000za 4500 9.806080 CaOODSP 20221107135816 cr ||||||||||| 150406s2000 onc ob f000 0 eng d CaOODSP eng eng fre n-cn--- Fs70-1/2000-110E-PDF Morgan, M. Joanne (Mary Joanne), 1961- Estimating spawning stock biomass in 2J3KL cod using a cohort maturation model and variable sex ratio [electronic resource] / M. Joanne Miller. Ottawa : Fisheries and Oceans Canada, 2000. 17 p. : fig., graphs. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/110 Includes bibliographic references (p. 6-7). Estimates of proportion mature at age and age at 50% maturity were produced for Div. 2J3KL cod using a cohort maturation model. For 2J3KL combined, age at 50% maturity has been declining for both males and females since the earliest cohorts that could be estimated. Differences between estimates of maturity from this method and the annual method are generally small but variable. Spawning stock biomass (SSB) produced using the two methods show similar trends with a maximum difference of 246,000 t and 26%. Estimates of proportion female at age were found to increase with age and were variable across time. Comparison of SSB using fixed and variable proportions female showed that the two methods produced similar trends with the variable sex ratio method generally producing higher estimates with a maximum difference of 31,000 t or 9%. When SSB produced using annual estimates of maturity and a fixed sex ratio was compared to SSB produced using cohort estimates of maturity and a variable sex ratio the maximum difference was 95,000 t and 27%. gccst Fisheries resources gccst Salt water fish gccst Fishing area gccst Fisheries management Canada. Department of Fisheries and Oceans. Canada. Canadian Stock Assessment Secretariat. Canadian Stock Assessment Secretariat research document, 1480-4883 ; 2000/110 (CaOODSP)9.507740 PDF 134 KB https://publications.gc.ca/collections/collection_2015/mpo-dfo/Fs70-1-2000-110-eng.pdf