A fine-scale multi-step approach to understand fish recruitment variability

• Published in: Scientific Reports
• Main Authors: Brosset, Pablo, Smith, Andrew Douglas, Plourde, Stéphane, Castonguay, Martin, Lehoux, Caroline, Van Beveren, Elisabeth
• Other Authors: Natural Sciences and Engineering Research Council of Canada visiting fellowship
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: Multidisciplinary; Northwest Atlantic
• Online Access: http://dx.doi.org/10.1038/s41598-020-73025-z; https://www.nature.com/articles/s41598-020-73025-z.pdf; https://www.nature.com/articles/s41598-020-73025-z

Abstract Recruitment is one of the dominant processes regulating fish population productivity. It is, however, notoriously difficult to predict, as it is the result of a complex multi-step process. Various fine-scale drivers might act on the pathway from adult population characteristics to spawning behaviour and egg production, and then to recruitment. Here, we provide a holistic analysis of the Northwest Atlantic mackerel recruitment process from 1982 to 2017 and exemplify why broad-scale recruitment–environment relationships could become unstable over time. Various demographic and environmental drivers had a synergetic effect on recruitment, but larval survival through a spatio-temporal match with prey was shown to be the key process. Recruitment was also mediated by maternal effects and a parent–offspring fitness trade-off due to the different feeding regimes of adults and larvae. A mismatch curtails the effects of high larval prey densities, so that despite the abundance of food in recent years, recruitment was relatively low and the pre-existing relationship with overall prey abundance broke down. Our results reaffirm major recruitment hypotheses and demonstrate the importance of fine-scale processes along the recruitment pathway, helping to improve recruitment predictions and potentially fisheries management.