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In temporally variable environments, longevity is generally considered to be a bethedging adaptation in which reproductive effort is spread across many years, increasing the probability that favorable conditions for larvae will be encountered at least some time in a female's life span. A long reproductive life span provides the potential for individual females to exhibit interannual differences in energy allocation patterns that may be age-or size-dependent. We examine the effects of maternal age and size on larval quality, fecundity, and timing of parturition in 5 species of live-bearing rockfishes in the genus Sebastes (blue, yellowtail, olive, gopher, and kelp rockfish), and compare these maternal effects with previously documented patterns in black rockfish Sebastes melanops. Larval quality was indexed by size (notochord length) and condition (lipid storage in the oil globule). Maternal effects were found for oil globule size in blue, yellowtail and gopher rockfish, for weight-specific fecundity in blue and yellowtail rockfish, and for parturition date in blue, yellowtail, and kelp rockfish. In all cases the maternal effects were similar to those reported for black rockfish, with increasing lipid provisioning of larvae, greater weight-specific fecundity, and earlier timing of parturition in the spawning season with increasing maternal age or size. No effect of maternal age or size on larval size was observed. In general, maternal effects were more evident in winter spawning species of the subgenus Sebastosomus (black, blue, olive, and yellowtail rockfish) than the spring spawning species of the subgenus Pteropodus (gopher and kelp rockfish). These results confirm that older and larger females in rockfish populations may contribute disproportionately to larval recruitment by producing higher quality larvae and more larvae per unit biomass, and releasing them at a different time than younger and smaller females. A shift in timing of parturition with female age may constitute a diversified bet-hedging strategy, providing a temporal spread of spawning effort within a maternal lineage, whereby successive female progeny release larvae at different times within the same year.
Sogard et al. (Wed,) studied this question.