Effect of temperature and feeding rate on the growth and survival of early and mid-stage phyllosomas of the spiny lobster Jasus edwardsii

Abstract

Stage I J. edwardsii larvae that had hatched from embryos held at one of three temperatures were reared at 12˚C to 24˚C and fed 2–3 mm brine shrimps. Larvae reared at 24˚, 21˚, 18˚, 15˚ and 12˚C moulted to Stage II after 7, 8, 11, 17 and 33 days respectively. Larvae from 18˚ and 15˚C embryos reared at 24˚C had 40% and 100% survival respectively. Larvae reared at 12˚C had 10–15% survival.

Stages II, IV, VI and VIII larvae were reared at three temperatures and fed 4, 8, 12, 16, 24 or 36 brine shrimp per day. At optimum feeding levels and at 24˚, 21˚ and 18˚C, Stage II larvae moulted after 6, 8 and 11 days respectively, Stage IV after 9, 10 and 12 days, Stage VI after 12, 14 and 17 days and Stage VIII after 18, 21 and 25 days. Survival was generally >70% but at 24˚C when fed >16 brine shrimp survival was <40%. For all stages, consumption rates increased but total consumption decreased with increasing temperature. For Stages II, IV, VI and VIII the intermoult period increased as the brine shrimp ration reduced. Larvae were successfully reared up to Stage VI ~25% faster at 21˚ than at 18˚C.