Larval Development of Ibacus peronii Leach (Decapoda: Scyllaridae) under Laboratory Conditions

Larvae from 3 adult Ibacus peronii were reared through 6 phyllosomal instars and a nisto before metamorphosing into juveniles. Two phyllosoma instars previously attributed to /. peronii (see Ritz and Thomas, 1973) were not observed during the present studies. We suggest that these belong to Ibacus alticrenatus. Six larvae successfully metamorphosed into nisto larvae and subsequently into juvenile stages. Of these juveniles, 3 were successfully cultured for 1 year on a diet of fresh mussels (Mytilus edulis). In a second experiment, larvae were reared at 2 temperature regimes (20.7° and 23.3°C). Considerably higher survival rates were achieved at the lower regime, although molting frequency decreased. During 1 year at ambient temperatures the juveniles developed from a mean carapace length of 12.2 mm at the first molt to 39.8 mm at the sixth molt. The mean intermolt period was 49 days.