PARENT SESSION
Contributed Oral Session 9: Marine Ecology: Disturbance; Dispersal; Recruitment
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 519 A, Level 5, Palais des congrès de Montréal

Physical and ecological correlates of longevity in Pacific rockfishes (Sebastes).

Kindsvater, Holly^{*,1, 3}, Bonsall, Michael², Mangel, Marc³, ¹ University of Florida, Gainesvillle, FL³ University of California-Santa Cruz, Santa Cruz, CA² Imperial College London, London, United Kingdom

ABSTRACT- 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 and size at maturity, and congeneric number) 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 a significant correlation between longevity, depth and body size in both cases. That the relationship exists even when accounting for phylogeny suggests that these traits are evolutionarily correlated, although much variation was not accounted for by any one trait. This approach allows us to evaluate the correlates of longevity and consider several alternative hypotheses for longevity (rate of living, caloric restriction, low extrinsic mortality). Our examination of this group makes a unique contribution to our understanding of Sebastes species' life history and the mechanisms underlying the evolution of longevity.

Key words: longevity, independent contrasts, Sebastes, rockfish