KINDSVATER, HK*; BONSALL, MB; MANGEL, M; Univ. of Florida; Univ. of Oxford; Univ. of California, Santa Cruz: Physical and Ecological Correlates of Longevity in Pacific Rockfishes (Sebastes)

We examined correlations in ecological and physical habitat traits of members of the genus Sebastes, a diverse group of fishes in the family Scorpaenidae that inhabit the North Pacific. Members of this genus exhibit a range of life history traits, the most striking of which is the extraordinary longevity of some species (>150 years). Life-history theory provides the expectation that ecological traits such as asymptotic body size, age at maturity and size at maturity, and community size are positively correlated with lifespan. Alternatively, physical traits of habitat such as depth (pressure), temperature, and oxygen metabolism may underlie physiological mechanisms explaining lifespan. We used raw species comparisons as well as phylogenetically independent contrasts in order to control for the possibility that the correlation in traits was due to evolutionary history. The phylogenetic analysis was conducted with the most recent phylogeny available for the group and with estimates of ecological traits (maximum size, age at maturity and size at maturity) and physical habitat traits (depth, temperature, and dissolved oxygen concentration) compiled from the literature. We used multiple regression of the explanatory variables against longevity for both the raw species comparisons and the independent contrast analysis. We found that after correcting for phylogenetic correlation, age and size at maturity were significant predictors of longevity. This approach allows us to evaluate the correlates of longevity and consider several alternative hypotheses for longevity (rate of living, low extrinsic mortality, phylogenetic inertia). Our examination of this group allows us to make a unique contribution to our understanding of Sebastes species� life history and the mechanisms underlying evolution of longevity.