The effect of trap type and water depth on puerulus settlement in the spiny lobster aquaculture industry in Indonesia

Spiny lobster farming is a feasible strategy to address increasing export demand currently not met by the capture fishery. However, farming currently relies on natural lobster seed availability, which in turn is limited by the fishers' lack of skill in catching and handling pueruli as well as applying suitable grow-out practises. In Indonesia, particularly on Lombok, a viable puerulus fishery has been established supporting a local grow-out industry. Anecdotal evidence suggests water depth may be an important factor for the effectiveness of collecting equipment. This paper reports on an experiment that examined the effect of depth and trap type on the effectiveness of puerulus collectors at the end of the wet season, when pueruli abundance is greatest. Four trap types were deployed at 5 depths: i) 1 m below surface; ii) 2 m below surface; iii) middle of the water column; iv) 1 m above the sea floor; and v) touching the sea floor, with 6 replicates of each. The data were analysed to identify the effect of depth and trap type using a two-way ANOVA. Significant differences for depth and trap type were found for the primary species caught, Panulirus homarus and Panulirus ornatus. The greatest catch of P. homarus was on the sea floor using a cement paper trap. For P. ornatus catch rate was less strongly correlated with a specific depth or trap type, although catch was highest at or near the sea floor in cement paper traps