Following the development of larval rearing technologies pioneered at the University of Tasmania’s, Institute for Marine and Antarctic Studies, commercial production of the spiny lobster Panulirus ornatus has commenced in northern Australia. However, low survival during juvenile culture represents a considerable bottleneck for the intensive onshore farming of this species. Mortality is primarily driven by cannibalism and can result in survival of <25% during early juvenile production. As in most crustacean species, cannibalism in P. ornatus typically occurs during and shortly after moulting when the animals are in the vulnerable “soft shell stage”. Providing protection from conspecific attacks around this event is fundamental to reducing the incidence of cannibalism. The development of culture systems to limit the impacts of cannibalism and optimise early juvenile survival and growth is likely crucial for commercialisation of this species to reach its full potential. We have been investigating a range of options to reduce cannibalism, including examining animal behaviour, optimising nutrition, genetics, and system design.
System design includes the use of both communal and individual culture systems as avenues to resolve this bottleneck. The use of hides for shelter from conspecific attack in communal tanks has provided no significant benefits in mitigating cannibalism, despite the many configurations tested. In communal culture, we have observed stocking density to have a significant effect on juvenile survival, whereas animal size does not appear to be important. This indicates that grading by size is unlikely to be a beneficial husbandry practice. Feeding frequency can be used to optimise growth in communal culture, however with increased moulting frequency there is increased opportunity for cannibalism of conspecifics. We observed higher feed intake, driven by conspecific competition, and increased growth in communal culture compared to those cultured individually; however individual culture can provide better survival and far greater gains in biomass. Despite better outcomes for managing cannibalism to date; based on the higher operation cost of individual culture we are continuing to develop novel communal culture systems, which are showing considerable promise.