Lipid class dynamics and the relationship between weight and length were analysed during early life stage (ELS) development in wild populations of shortbelly rockfish Sebastes jordani to investigate their utility in a condition or nutritional status assessment. Analyses from more than 3000 field-captured shortbelly rockfish indicated little variation in weight for a given length and provided limited application in the assessment of condition. The fractionation of total lipids into individual classes revealed trends in lipid metabolism throughout development. These trends were described best using a stage-specific regression model, since Sebastes show defined early life history transitions. Among developmental stages, triacylglycerols (TAG) and polar lipids (PL) were the dominant lipid classes and cholesterol (CHOL), sterol/wax esters, and nonesterified fatty acids were found in lower concentrations. In the preflexion stage, low concentrations and constant levels of TAG along with the combined influence of endogenous and exogenous sources of energy compromised the use of TAG as an index of nutritional status. However, during flexion through juvenile stages, TAG levels increased indicating an accumulation of energy reserves with development, thus providing a valid indicator of nutritional status in later stages. Large fluctuations in PL concentrations during development suggested complex metabolism which may be due to changes in cell volume and cell membrane proliferation with development as well as catabolism. CHOL declined in larval stages, then remained constant with increasing size through the juvenile stage, negating its use as a normalizer for variations of mass in a TAG/CHOL ratio prior to juvenile transformation. This study provides the first documentation of lipid dynamics during early life stages following parturition in a marine viviparous teleost.

In yellowtail rockfish (Sebastes fiavidus), lipids that accumulated in mesenteries and liver during the summer and early fall upwelling were subsequently translocated to developing ovaries during late fall and winter. Tissue and serum lipids were assessed by stage of ovary maturation from fish collected monthly over six annual reproductive cycles (1985–91) from Cordell Bank, a seamount off central California. Lipids were primarily transported to ovaries prior to fertilization. Energetic lipids (triglycerides, nonesterified fatty acids) were maximal in serum during yolk accumulation stages and declined significantly during embryonic stages. Between fertilization and parturition, lipid and protein content of ovaries declined by about 21%, a value approaching the minimum for lecithotrophy (i.e. ovoviviparity). During gestation, however, serum phospholipids and calcium (vitellogenin surrogate) were significantly elevated relative to male levels, suggesting matrotrophic contributions. A reproductive mode that is primarily lecithotrophic but supplemented by maternal inputs during embryogenesis would be beneficial to viviparous fishes of the California coast. This strategy may optimize reproduction by coupling the disparate times of food abundance and gestation, yet allow for provision of nutrients late in the reproductive cycle should they be available.

Triacylglycerols (TAG) were the dominant lipids in liver tissue of both sexes of the viviparous yellowtail rockfish Sebastes flavidus during the spring and summer when greatest feeding occurred. Significant declines in liver TAG during the winter corresponded to increased concentrations of polar lipids (PL), the main component of cell membranes. Elevated PL in female livers relative to those of males preceded the period of ovarian enlargement and may be attributed to the production of vitellogenin. During late vitellogenesis and gestation, ovaries contained significantly elevated concentrations of PL, TAG, and cholesterol. Since yellowtail rockfish are highly fecund and viviparous, large quantities of ovarian PL are required for proliferation of the cell membranes in developing larval tissues. TAG accumulated in ovaries in lower concentrations than PL and were likely metabolized as the main source of energy during gestation. This pattern of ovarian PL concentrations exceeding those of TAG and the presence of oil globules, may be unique to highly fecund, viviparous teleosts and signify an alternative profile to those previously documented for oviparous species. Testes at maximum I G were only 7% of maximum ovarian size, composed of mainly PL, and lacked a defined lipid dynamic pattern across the reproductive cycle. 1999 The Fisheries Society of the British Isles

We assessed growth in subyearling chinook salmon (Oncorhynchus tshawytscha) during the 1998 El Niñ o and 1999 La Niñ a in the Gulf of the Farallones, a region of the continental shelf off central California seaward of the Golden Gate and the southernmost ocean entry point for the species in North America. Juvenile salmon demonstrated greater growth during this strong El Niñ o, when water temperature anomalies of more than +3°C were recorded at local buoys, than during the similarly strong 1999 La Niña.

Total mean gestation period of all female yellowtail rockfish Sebastes flavidus, from fertilization to parturition, was 29·2 days. Hatching occurred 23 days after fertilization, followed by 6 days of larval incubation. Eggs varied in dry mass and energy content with lipid concentrations contributing the greatest amount of energy per egg. The endogenous energy of the yolk and oil globule declined throughout gestation resulting in limited yolk and oil reserves at parturition.