Combined Effects of Prey Concentration and Photoperiod on Sirvival and Growth of Larval Sea Bream Archosargus rhomboidalis (Sparidae)

Abstract

Effects of prey concentrations and photoperiods on survival and growth of larval sea bream A. rhomboidalis (Sparidae) were determined in laboratory experiments. Larvae were reared from eggs to 16 days after hatching on copepod nauplii at 25, 50, 100 or 500 l-1 combined with photoperiods of 7, 13 or 19 h light. Survival was highest at 13 h light duration and increased as the prey level was raised. Growth was best at 13 h light when prey concentrations were 100 or 500 l-1,1, but was best at 19 h light when prey concentrations were 25 or 50 l-1. At high prey levels, the larvae survived and grew best at ambient light durations; at low prey levels they benefited in growth, but not in survival, from a longer than normal photoperiod.