Intrinsic optimum temperature for the development of decapod crustacean larvae based on a thermodynamic model

Abstract

A nonlinear thermodynamic Sharpe-Schoolfield-Ikemoto (SSI) model has been applied to temperature-dependent development of some arthropods and other ectotherms. The most important parameter estimated by the SSI model is the intrinsic optimum temperature (T φ), which is the temperature at which the probability of an enzyme being in its active state is maximal. It has been also suggested that T φ authentically represents the optimal ambient temperature for fitness in ectotherms. We applied the SSI model to larvae of four aquatic decapod crustacean species distributed in cold, temperate, and tropical waters for understanding thermal adaptation in decapods. As a result, T φ 's estimates for the larvae corresponded to the optimum temperatures for larval survival/growth. The estimates also changed in accordance with the geographical distribution of the stages, species, and populations studied, i.e., 6.91-9.06 °C for cold-water species and 19.68-27.00 °C for temperate and tropical species. It would be useful to examine the relationship between changes in geographical distribution with temperature T φ and population size for a better understanding of population fluctuations under global climate change. Additionally, stable aquaculture production could be enhanced if the temperature conditions of each life history stage were controlled at T φ.