Effects of temperature and food density on the survival and growth of early stage phyllosoma of the western rock lobster, Panulirus cygnus

Abstract

Stages I, II and III phyllosoma larvae of the western rock lobster, Panulirus cygnus, were reared at all combinations of three temperatures (19, 22 or 25 °C) and three Artemia densities (1, 5 or 10 ml −1). The survival of larvae within each stage at these combinations did not significantly differ. Increases in temperature significantly reduced the intermoult period for all stages tested. Stages I and II larvae reared at 19 °C were significantly larger after moulting than larvae reared at the higher temperatures; however, this was not found with stage III larvae. Increases in food density had little effect on the intermoult period or postmoult size at any stage. Feeding above 1 Artemia ml −1 made no difference to the intermoult period or postmoult size, suggesting that ≤1 Artemia ml −1 is the minimum for optimum growth. Rearing larvae at 25 °C significantly reduced the intermoult period; however, it also reduced the postmoult size of stages I and II larvae, indicating that a compromise between rapid development and larval growth is needed when determining an optimum rearing temperature. A temperature of 22 °C is recommended.