The impact of long-term overfishing on the abundance dynamics of early- and late-maturing Northeast Arctic cod ...

• Main Author: Tretyak, V. L.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ASC 2002 - Y - Theme session 2024
• Subjects: Fisheries and aquaculture; Pressures, impacts, conservation, and management; Arctic cod; Arctic; Northeast Arctic cod
• Online Access: https://dx.doi.org/10.17895/ices.pub.25443637.v1; https://ices-library.figshare.com/articles/conference_contribution/The_impact_of_long-term_overfishing_on_the_abundance_dynamics_of_early-_and_late-maturing_Northeast_Arctic_cod/25443637/1

No abstracts are to be cited without prior reference to the author.An algorithm is proposed for estimating age composition and abundance of cod spawning for the first time and repeat spawners in each calendar year. A fine structure of the Northeast Arctic cod spawning population was studied for a fairly long historical period from 1949 to 1997. It was shown that cod could be divided into at least two groups of spawners, early- and late-maturing individuals, which long-term abundance dynamics were different. Abundance of late-maturing cod displayed a marked decreasing trend over the entire time series, while the abundance of early-maturing cod has been steadily increasing since the early 1960’s. Structural change in the mature part of the population took place against the background of the long-term overfishing. A hypothesis is proposed about inter- and intra-annual qualitative heterogeneity of the spawners. Parameters of deterministic basis of the recruitment process (a sum of two Ricker’s stock-recruitment ...