Influence of temperature on energy utilization and growth of embryonic and prolarval American plaice, Hippoglossoides platessoides (Fabricius)

Abstract

Embryos and yolk-sac larvae of American plaice, Hippoglossoides platessoides (Fabricius), were incubated at 2, 6, 10, and 14°C. Although there was a positive relationship between development rate and temperature from 2–10°C, all embryos died at 14°C. Temperature influenced length, weight, and relative proportions of yolk and larval tissue at hatching and at yolk-sac absorption. Yolk-sac volume decreased exponentially over time at all temperatures. Rate of growth in length was fastest at 10°C, intermediate at 6°C, and slowest at 2°C, and larval tissue weight increased curvilinearly at all temperatures. Overall yolk utilization efficiencies, from fertilization to yolk-sac absorption, were 50.3, 44.0, and 35.7% at 2, 6, and 10°C, respectively. These results indicate that temperatures ≥14°C are above the upper thermal limit for successful reproduction in this species. Although embryos and larvae can survive at 10°C in the laboratory, their relatively small size at yolk-sac absorption indicates that they would experience high predation and starvation rates in nature. Conversely, the larger size of larvae incubated at cooler temperatures (2–6°C) indicates that they would have a greater probability of surviving and initiating feeding.