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 temper ature when using effective day-degrees (D-eff(o)) as an index of developmen t. The calculation of D-eff(o) is based on the principle of thermal summati on whereby the rate of development is linearly related to the ambient tempe rature above a species-specific threshold temperature (T-0) at which develo pment 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 regardl ess of incubation temperature when using D-eff(o) as the index of developme nt. Previous attempts to relate physiological processes in poikilothermic a nimals, including fish, to incubation temperature are discussed. (C) 1999 E lsevier Science B.V. All rights reserved.