Growth of the spiny lobster Panulirus homarus was studied by communal as well as individual rearing.In experiment 1,the lobsters were grown together at the bottom of the tank without pro-viding shelter while individually reared lobsters were kept in rect-angular, interconnected compartments floated on the surface of the same tank (phase I). After 9 months, the conditions were reversed (phase II)i.e., the lobsters in individual compartments were released to the bottom and those at the bottom were shifted to individual rearing. Phase II continued for 10 months. In the first phase, the lobsters grown together at the bottom of the tank had a weight increase of 0.54 g/day, moulting 4.27 times, while those grown in individual compartments increased their weight by 0.15 g/day, moulting 3.44 times. In phase II,the lobsters shifted to individual rearing had a reduced growth rate of 0.17 g/day with an average moult of 4.06. On the other hand, the lobsters shifted to communal rearing had substantial increase in growth rate from 0.15 g/day to 0.47 g/day and moulted 6.11 times. In experiment 2, lobst-ers were grown in bigger individual compartments at the bottom of the tank, in which, a weight increase of 0.29 g/day and an average moult of 7.25 were obtained in 16 months.In experiment 3,the growth rate of lobsters was determined with and without providing shelter. In 8 months, the lobsters provided with shelter grew from 76.64± 11.62 g to 36.30±20.87 g, a weight increase of 0.25 g/day with an average moult of 4. The lobsters in the tank without shelter had a growth rate of 0.33 g/day (82.73±12.82 g to 161.49±36.13 g) with an average moult of 4.31. Survival was 100% in the tank without shelter and 75% in the tank with shelter. The lobsters in communal rearing were gregarious and had physical contact, which might play a role in inducing moulting and growth.

Panulirus homarus, moulting, palinurid, spiny lobsters