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

Concentrations of lipids and protein were measured in embryos during gestat ion in two species of viviparous rockfishes off the central California coas t. Total lipids and protein declined linearly through embryonic maturation in semipelagic yellowtail rockfish, Sebastes flavidus, and pelagic shortbel ly rockfish, Sebastes jordani. Energetically, lipids were the predominant s ource of energy for embryonic development in both species, but lipid and pr otein catabolism was significantly greater for yellowtail rockfish. Total l ipids, protein, and lipid class composition were measured during embryonic maturation in three populations of shortbelly rockfish, located at Ascensio n, Pioneer, and Bodega submarine canyons, to determine intraspecific variab ility of nutritional dynamics. Triacylglycerols and polar lipids (mostly ph ospholipids), the predominant lipid classes in all maturation stages, were depleted through embryonic development. Steryl or wax esters and cholestero l 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 bir th, thus providing a measure of nutritional condition, or qualitative repro ductive success. Analyses determined that there were significant difference s in metabolism and estimated concentrations at birth of nutrients between the two species and among the shortbelly rockfish populations, indicating d ifferential potential for survival during early planktonic life stages unti l favorable feeding conditions occur. Results suggest that the contribution of individual populations to the diversity of metapopulations or year clas ses may be influenced by the nutritional condition of larvae at birth.