Abstract
Differences in maternal investment and reproductive timing can have important con- sequences for offspring survival. Prior studies on nearshore rockfishes have shown significant effects of maternal age and size on the timing of parturition, fecundity, and larval quality, offering advantages to population persistence by maintaining age diversity in rockfish populations. In this study, reproduction in chilipepper Sebastes goodei, widow rockfish S. entomelas, and yellowtail rockfish S. flavidus was examined to determine whether age- and size-related effects on maternal investment and reproductive timing are exhibited in deeper-dwelling species of this genus. Par- turition dates were derived from fine-scale staging of pre-parturition embryos from gravid females. Measurements of embryonic energy reserves (oil globule and yolk), indicators of condi- tion, were used to estimate depletion rates and to test for maternal age and size effects on larval quality. For widow and yellowtail rockfish, larger or older rockfish gave birth earlier in the partu- rition season than younger, smaller fishes. Maternal factors of weight, length, or age were posi- tively correlated to absolute and relative (weight-specific) fecundity in all species. A trade-off was observed between egg size and fecundity among species, with chilipepper displaying larger egg size and lower fecundity relative to widow and yellowtail rockfish. Embryonic reserves were weakly but significantly related to age only in chilipepper, with embryos from larger, older moth- ers having larger oil globules. Since the strength of maternal effects varies among Sebastes species, information on maternal influence can assist managers in identifying species most likely to benefit from the protection of age structure afforded by marine reserves or other fisheries regulations.
Highlights
The commercial, recreational, and ecological importance of rockfishes Sebastes spp. merit additional early life history research to understand factors determining their recruitment success or failure
This study extends our understanding of maternal effects to deep-water rockfishes, examining the timing of parturition, fecundity, and larval quality
This study investigates whether age- and sizerelated effects in maternal investment and reproductive timing are exhibited in deeper-dwelling species of this genus
Summary
The commercial, recreational, and ecological importance of rockfishes Sebastes spp. merit additional early life history research to understand factors determining their recruitment success or failure. Knowledge of species-specific reproductive phenologies and factors determining both the quality and quantity of offspring is integral to evaluating. Rockfishes are among the longest-lived marine fishes along the Pacific coast (Cailliet et al 2001) and do not display reproductive senescence (de Bruin et al 2004). Species north of central California typically extrude 1 brood per year, whereas some southern populations may have an additional brood (MacGregor 1970, Wyllie Echeverria 1987, Love et al 2002). High fecundity and typically long reproductive lifespan in rockfishes serve as a bethedging strategy to buffer against high variability in recruitment success in the physically dynamic environment of the Northeast Pacific (Leaman & Beamish 1984, Longhurst 2002)
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