Maternal influence on timing of parturition, fecundity, and larval quality in three shelf rockfishes (Sebastes spp.)

Abstract

Differences in maternal investment and reproductive timing can have important consequences 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. Parturition 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 condition, 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 parturition season than younger, smaller fishes. Maternal factors of weight, length, or age were positively 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 mothers 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.

Effects of size-dependent relative fecundity specifications in fishery stock assessments

“…For example, it has long been recognized that some rockfish species, including Chilipepper, produce multiple broods, complicating efforts to accurately estimate annual fecundity (Beyer et al, 2015;Stafford et al, 2014). If the likelihood of multiple broods increases with female size or age, but is difficult to document (due to covariation with female condition, climate and the difficulties in identifying a secondary brood), then the relative reproductive contribution of females exhibiting such patterns may be underestimated.…”

“…Although this stock was also estimated to be at low levels (just above 25% of the unfished level) during the late 1990s, it was assessed to be healthy in 2007, at around 70% of the unfished biomass. Although the 2007 assessment assumed constant Ф rel , Beyer et al (2015) and Stafford et al (2014) have recently reported a reasonably strong size-dependent Ф rel relationship. We used the 2007 model, updated to utilize the most recent stock synthesis software (Methot and Wetzel, 2013), to evaluate the differences in assessment results with and without a size-dependent Ф rel .…”

The role of maternal age and context-dependent maternal effects in the offspring provisioning of a long-lived marine teleost

“…Previous research on rockfish parturition timing has found older females begin releasing larvae earlier in the season than younger females [ 17 , 21 , 22 ]. As such, we modelled larval OGV as a function of both maternal age and parturition timing.…”

Maturity, Spawning Omission, and Reproductive Complexity of Deepwater Rockfish

“…This indicates the importance of older and larger rockfish females disproportionately contributing to the productivity of these stocks. In many rockfish species, the older and/or larger females display increased relative fecundity (Beyer et al 2015), higher larval quality (Berkely et al 2004), and more protracted or earlier spawning periods (Sogard et al 2008;Stafford et al 2014). Additionally, larger rockfish potentially have larger energy reserves and therefore possess the ability to energetically support spawning during less-favorable environmental conditions (Schultz et al 2011).…”

“…Additionally, larger rockfish potentially have larger energy reserves and therefore possess the ability to energetically support spawning during less-favorable environmental conditions (Schultz et al 2011). The strength of maternal effects appears to vary among species, and it is important to identify species with strong maternal effects, as they may benefit from the protection of age structure (Stafford et al 2014). There is increasing evidence that the contribution of large or old females to the recruitment of rockfishes and other teleost species is significant, and fishery-mediated truncation of the size or age structure of these populations should be considered (Vallin and Nissling 2000;Beldade et al 2012;Hixon et al 2014).…”