Nutritional dynamics during embryonic development in the viviparous genus Sebastes and their application to the assessment of reproductive success


MacFarlane, R. Bruce, and Elizabeth C. Norton
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Concentrations of lipids and protein were measured in embryos during gestation in two species of viviparous rockfishes off the central California coast. Total lipids and protein declined linearly through embryonic maturation in semipelagic yellowtail rockfish, Sebastes flavidus, and pelagic shortbelly rockfish, Sebastes jordani. Energetically, lipids were the predominant source of energy for embryonic development in both species, but lipid and protein catabolism was significantly greater for yellowtail rockfish. Total lipids, protein, and lipid class composition were measured during embryonic maturation in three populations of shortbelly rockfish, located at Ascension, Pioneer, and Bodega submarine canyons, to determine intraspecific variability of nutritional dynamics. Triacylglycerols and polar lipids (mostly phospholipids), the predominant lipid classes in all maturation stages, were depleted through embryonic development. Steryl or wax esters and cholesterol also declined, but were in much lower concentrations. The goodness-of-fit of linear regressions for protein, total lipid, and lipid classes by stage of embryonic maturation allowed estimations of their concentrations at birth, thus providing a measure of nutritional condition, or qualitative reproductive success. Analyses determined that there were significant differences in metabolism and estimated concentrations at birth of nutrients between the two species and among the shortbelly rockfish populations, indicating differential potential for survival during early planktonic life stages until favorable feeding conditions occur. Results suggest that the contribution of individual populations to the diversity of metapopulations or year classes may be influenced by the nutritional condition of larvae at birth.