Temperature, maternal effects and density-dependent processes during early life stages of Argentine hake as relevant recruitment drivers

Abstract

We analyzed the annual variability in total egg production and recruitment of the Patagonian stock of Argentine hake since 1990 and correlated these indices with some environmental variables as temperature and larval density estimated in the spawning area. We used data from research surveys carried out between 2001 and 2018 during the reproductive peak of this stock and information from the assessment model. The optimal spawning area of Argentine hake was associated with a bottom thermal front, with temperature values between 9° and 13 °C. The study revealed that reproductive success is positively influenced by the oldest females of the stock and negatively influenced by the egg density in the spawning area. In the first case, a larger proportion of older spawning females (≥ 7 years-old) produces larvae with greater survival rates; while in the second case, a greater abundance of early larvae in a more limited optimum spawning area could produce a higher rate of mortality due to competition.