Despite evidence of maternal age effects in a number of teleost species, there have been challenges to the assertion that maternal age intrinsically influences offspring quality, with alternative arguments for the role of environmental context in maternal effects. Much of this discussion has centered on the rockfishes of the northeast Pacific (genus Sebastes) with the reproductive strategies of this group becoming a focus of evolutionary, conservation, and fisheries science. We examine both age-specific and context-dependent reproductive strategies in one of the long-lived rockfishes to identify and explore their impact on offspring provisioning. Using offspring release timing as a proxy for offspring environment, we show that offspring provisioning is a function of both maternal age and release timing, but with opposite effects on offspring provision. Provisioning increases with maternal age but decreases with release date independent of maternal age. Despite a universal decrease in offspring provisioning as the spawning season progressed, older females maintain a higher level of per offspring provisioning than younger females. These findings suggest a role for both maternal age and context-dependent maternal effects, mediated by the offspring release environment. The opposing nature of the maternal age and context-dependent maternal effects on offspring provisioning carries important implications for modeling the population-level dynamics and productivity of a harvested stock and the value of maintaining the age structure within long-lived fished populations.
Linsey M. Arnold, Department of Fisheries and Wildlife, Oregon State University
Wade D. Smith, University of British Columbia, Vancouver, British Columbia, Canada
Paul D. Spencer, NOAA Alaska Fisheries Science Center, Seattle, WA
Allison N. Evans, Department of Fisheries and Wildlife, Oregon State University
Scott A. Heppell, Department of Fisheries and Wildlife, Oregon State University
Selina S. Heppell, Department of Fisheries and Wildlife, Oregon State University
North Pacific Research Board, project number 629