Influence of temperature on yolk utilization by the white sturgeon, Acipenser transmontanus

The utilization of yolk nutrients by the white sturgeon was investigated at incubation temperatures of 11, 14, 17, and 20° C. The rates of development and dry matter loss are temperature dependent, with an upper critical temperature between 17 and 20° C above which survival is reduced (the temperature range investigated was not sufficient to allow determination of a lower critical temperature). The patterns of yolk utilization are similar to those of other fish. Protein depletion occurs at relatively constant rates throughout yolk nutrition, with the highest rate observed at 20° C. More than 95% of the original lipid levels were still present at hatch, except at 20° C (88%). After hatch, lipid content rapidly decreased at all temperatures, with fish incubated at 11° C possessing higher lipid levels at yolk depletion. The question of why the temperature tolerances of early life stages are more limited than those of older fish is discussed.