Effect of temperature on the egg and yolk-sac larval development of common pandora, Pagellus erythrinus

Temperature is one of the most critical environmental factors for fish ontogeny, affecting the developmental rate, survival and phenotypic plasticity in both a species- and stage-specific way. In the present paper we studied the egg and yolk-sac larval development of Pagellus erythrinus under different water temperature conditions, 15°C, 18°C and 21°C for the egg stage and 16°C, 18°C and 21°C for the yolk-sac larval stage. The temperature-independent thermal sum of development was estimated as 555.6 degree-hours above the threshold temperature (the temperature below which development is arrested), i.e. 7°C for the egg and 12.1°C for the yolk-sac larval stage. Higher hatching and survival rates occurred at 18–21°C. At the end of the yolk-sac larval stage, body morphometry differed significantly (p<0.05) between the temperatures tested. The growth rate of the total length increased as temperature rose from 16°C to 18°C, while in the range of 18–21°C it stabilized and was independent of water temperature. The estimated Gompertz growth curve for the yolk-sac larvae of P. erythrinus was \( {\text{TL}} = 3.035 \cdot {\text{e}}^{{ - 0.505 \cdot {\text{e}}^{{ - 0.041 \cdot t}} }} \) (r2=0.992) for the 16°C, \( {\text{TL}} = 2.926 \cdot {\text{e}}^{{ - 0.509 \cdot {\text{e}}^{{ - 0.106 \cdot t}} }} \) (r2=0.991) for the 18°C and \( {\text{TL}} = 2.801 \cdot {\text{e}}^{{ - 0.482 \cdot {\text{e}}^{{ - 0.104 \cdot t}} }} \) (r2=0.981) for the 21°C treatment. The efficiency of vitelline utilization during the yolk-sac larval stage was higher at 18°C.