Key drivers and spatio-temporal variation in the reproductive potential of Icelandic cod

Le résumé fourni par la source

Abstract Total egg production (TEP) is a measure of reproductive potential, which along with early survival of larvae, can be affected by maternal factors. Icelandic cod experienced a drastic reduction in abundance from the 1950s to the mid-1990s, followed by an increase in spawning stock biomass (SSB) from 2010. However, large year classes have been infrequent in the past four decades. In this study, temporal and spatial variability in TEP in relation to female age diversity and mean length was explored at seven different spawning regions around Iceland. The results show that TEP increased substantially with increasing SSB and was also influenced by both mean length and age diversity of females, although these effects were inconsistent across spawning regions. Furthermore, survival ratio from TEP to 1 year old has decreased over time. A negative relationship between TEP and survival ratio indicates that density-dependent factors likely caused higher mortality during the first year of life. Thus, density dependence appears to have partially offset the positive effect of increased SSB on recruitment.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.