Life in the fast lane: Revisiting the fast growth—High survival paradigm during the early life stages of fishes

Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth-Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distribution of growth histories with age towards faster growth rates relative to the initial population because slow-growing individuals are subject to high mortality (via starvation and predation). However, mortality data compiled from 387 cases published in 153 studies (1971–2022) showed that the GSP was only supported in 56% of cases. Selection against slow growth occurred in two-thirds of field studies, leaving a non-negligible fraction of cases showing either an absence of or inverse growth-selective survival, suggesting the growth-survival relationship is more complex than currently considered within the GSP framework. Stochastic simulations allowed us to assess the influence of key intrinsic and extrinsic factors on the characteristics of surviving larvae and identify knowledge gaps on the drivers of variability in growth-selective survival. We suggest caution when interpreting patterns of growth selection because changes in variance and autocorrelation of individual growth rates among cohorts can invalidate fundamental GSP assumptions. We argue that breakthroughs in recruitment research require a comprehensive, population-specific characterization of the role of predation and intrinsic factors in driving variability in the distribution and autocorrelation of larval growth rates, and of the life stage corresponding to the endpoint of pre-recruited life. -- Keywords : critical period ; growth-mortality ; individual characteristics ; larval physiology ; predation ; recruitment endpoint

Reproduction of greater amberjack (Seriola dumerili) and other members of the family Carangidae

The family Carangidae contains several species of aquaculture interest, including the amberjacks, yellowtails and trevallies. Among them, the greater amberjack (Seriola dumerili), the Japanese amberjack or yellowtail (Seriola quinqueradiata) and the yellowtail kingfish (Seriola lalandi) are considered the species with the highest potential for commercial aquaculture. Understanding the reproductive physiology–biology, spawning kinetics and production characteristics in captivity are of utmost importance for the domestication of any animal, and developing broodstock management methods and therapies to optimize egg production and overcome potential reproductive dysfunctions are essential. The present article reviews the available literature on the reproductive biology of the Carangidae species of interest for the aquaculture industry, both in the wild and under farming conditions. The reproductive traits of wild and farmed fish, whenever available, were compared in order to improve the understanding of the reproductive dysfunctions occurring in captivity. Finally, the hormonal maturation and spawning induction protocols examined so far to ameliorate the reproductive dysfunctions and obtain fertile gametes are summarized, and their effectiveness in the different rearing conditions is discussed