Resolving associative patterns in life history parameters among marine fish stocks in the Northeast Pacific Ocean

Abstract

Knowledge of life history characteristics in marine fishes, including natural mortality, somatic growth, maturity schedule, productivity and others, is essential for successful management and long-term sustainability of marine resources. Patterns exist among these traits within and among taxa to maximize individual fitness and offspring survival, and trade-offs are typical. In this study, we examined life history data from 42 fishery stocks in the Northeast Pacific Ocean using principal component analysis (PCA) and clustering techniques. We identified discrete clustering patterns of stocks corresponding to ecological, taxonomic, and management criteria. Our results revealed additional resolution for complex structure among stocks based on combinations of life history traits, well beyond what was described before, for the diverse group of Sebastes rockfish, which have not been examined in this context previously. One example is clear differentiation between Sebastes demersal species, and those caught with midwater gear, particularly with addition of stock-specific fecundity data; another is bocaccio rockfish, whose life history patterns our results shed new light on. Our results also provide an empirical basis for grouping stocks in meta-analytic studies, which are often used to inform unknown or difficult to estimate parameters in stock assessment. Our results supported important core aspects of previous studies, and rectified others, among a wide range of stocks including highly migratory, coastal pelagic and groundfish stocks. They also reinforce fishery management strategies grounded in life history, among stocks in the Northeast Pacific Ocean and around the world.