Abstract

The effects of temperature on growth of phyllosomas of the Japanese spiny lobster Panulirus japonicus were investigated. Phyllosomas were individually reared at four temperatures (20°, 22°, 24° and 26°C), and intermoult period and moult increment were monitored. The improved Bêlehrádek’s equation, G = aL^b (T–α)^c(β–T)^d, was used to describe the relationship between growth characters (G: intermoult period, moult increment or daily growth increment), body length (L) and temperature (T), with a and b being constants that change at 17·8 mm body length, c and d being common constants for all sizes, and α and β being the conceptual biological lower and upper critical temperatures, which are variables with body length. The intermoult period increased and the moult increment decreased with decreasing temperature. However, a negative influence on both the intermoult period and the moult increment was observed at 26°C for medium-sized and large phyllosomas. The largest daily growth increment was obtained at 26°C up to 15·0 mm body length, and then at 24°C. This indicates that the optimum temperature for growth decreases from 26° to 24°C at 15·0 mm body length. This optimum temperature for growth seemed to be optimal for survival.