Influence of Temperature on Energy Utilization of Embryonic and Prolarval Tautog, Tautoga onitis

When daily energy budgets were calculated by two methods for tautog, Tautoga onitis, from fertilization to complete yolk absorption at three temperatures (16, 19, and 22 C), neither method indicated a deficiency of yolk energy for growth and metabolism prior to exogenous feeding capability. Deficits were indicated on the day of feeding capability at all temperatures by the oxygen consumption method, the more precise but less inclusive of the two. The dry weight method, which gave the more conservative estimates, indicated no deficit for the entire period of yolk absorption at 16 C, a deficit one day after feeding capability at 19 C, and a deficit on the day of feeding capability at 22 C.Regression analysis of oxygen consumption indicated that 22 C may be in the upper temperature limits for normal metabolism by embryonic and prolarval tautog. Yolk utilization efficiencies and postlarval size at complete yolk absorption tended to be inversely related to temperature. The ecological implications and the effec...