A meta-analysis of fecundity in rockfishes (genus Sebastes)

Estimates of fecundity at size are a key component of age-structured population dynamics models such as those used for stock assessment purposes. Fecundity-length relationships for many exploited fish stocks are often poorly understood due to small sample sizes and high levels of intrinsic variability among individuals. Several species in the genus Sebastes match this description, and are important components of commercial and recreational fisheries off the U.S. West Coast. We used a hierarchical Bayesian modeling framework for simultaneous estimation of parameters in the fecundity-length relationships for 29 species of rockfish while accounting for variability within and among subgenera. Hierarchical models that account for subgeneric phylogenetic structure and variability among species outperformed models that treat all species in the genus as exchangeable or ignored variation among species within a subgenus, based on a predictive information criterion. Our results confirm that weight-specific fecundity increases with size in nearly all Sebastes species, and that the assumption of proportionality between mature female biomass and total egg production is inappropriate for most Sebastes stock assessments. Benefits of the hierarchical framework include prediction of fecundity-length parameters at the genus, subgenus, and species level, as well as predictive distributions for unobserved Sebastes species.