An updated life-history scheme for marine fishes predicts recruitment variability and sensitivity to exploitation

Aim Patterns of population renewal in marine fishes are often irregular and lead to volatile fluctuations in abundance that challenge management and conservation efforts. Here, we examine the relationship between life-history strategies and recruitment variability in exploited marine fish species using a macroecological approach. Location Global ocean. Time period 1950-2018. Major taxa studied Bony and cartilaginous fish. Methods Based on trait data for 244 marine fish species, we extend the established equilibrium-periodic-opportunistic (E-P-O) life-history classification scheme objectively to include two additional emergent life-history strategies: bet-hedgers (B) and salmonic (S) strategists. The B strategists include rockfishes and other species inhabiting patchy benthic habitats with life histories that blend characteristics of E and P species; they combine very long life spans with elevated investments in both parental care and fecundity. The S strategists mainly comprise salmonids that share life-history characteristics with E and O species: elevated investments in parental care reminiscent of E strategists, but with reduced fecundity and short life spans characteristic of O species. We analysed how the E-B-P-O-S life-history classification mapped onto patterns of recruitment variability observed in population time series data (n = 156 species). Results Generalized linear models suggested that life-history strategy explained a modest, yet significant amount of recruitment variability across species. Greater predictive power arose after controlling for increased recruitment variance associated with variable fishing pressure, with O strategists showing the strongest sensitivity. The B strategists were susceptible to exploitation in a similar manner to P stocks, but their longer times to maturity made them particularly vulnerable to overfishing. Main conclusions A broader recognition of the distinct ecology of salmonic and bet-hedger groups is important when studying life-history strategies in marine fish. More generally, our results stress the importance of considering life-history strategies for understanding patterns of recruitment variability across fish stocks.

Automated summary

The study examines the relationship between life-history strategies and recruitment variability in exploited marine fish species. It finds that life-history strategy explains a modest yet significant amount of recruitment variability across species, with O strategists showing the strongest sensitivity. B strategists are susceptible to exploitation similar to P stocks, but are particularly vulnerable to overfishing due to longer times to maturity.