LARVAL DEVELOPMENT OF IBACUS-PERONII LEECH (DECAPODA, SCYLLARIDAE) UNDER LABORATORY CONDITIONS

Larvae from 3 adult Ibacus peronii were reared through 6 phyllosomal i nstars and a nisto before metamorphosing into juveniles. Two phyllosom a instars previously attributed to I. peronii (see Ritz and Thomas, 19 73) were not observed during the present studies. We suggest that thes e belong to Ibacus alticrenatus. Six larvae successfully metamorphosed into nisto larvae and subsequently into juvenile stages. Of these juv eniles, 3 were successfully cultured for 1 year on a diet of fresh mus sels (Mytilus edulis). In a second experiment, larvae were reared at 2 temperature regimes (20.7 degrees and 23.3 degrees C). Considerably h igher survival rates were achieved at the lower regime, although molti ng frequency decreased. During 1 year at ambient temperatures the juve niles developed from a mean carapace length of 12.2 mm at the first mo lt to 39.8 mm at the sixth molt, The mean intermolt period was 49 days .