Temperature dependency of early growth of turbot (Scophthalmus maximus L.) and its implications for developmental progress

Growth in developing turbot larvae can be expressed independently of temperature when using effective day-degrees (D-eff(o)) as an index of development. The calculation of D-eff(o) is based on the principle of thermal summation whereby the rate of development is linearly related to the ambient temperature above a species-specific threshold temperature (T-0) at which development is theoretically arrested. The T-0 for turbot embryos is 5.3 degrees C. The increase in wet body mass of developing turbot larvae at 14, 18, and 22 degrees C can be aligned into a single exponential relationship regardless of incubation temperature when using D-eff(o) as the index of development. Previous attempts to relate physiological processes in poikilothermic animals, including fish, to incubation temperature are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.