Spiny lobster population enhancement: Moderation of emergence behaviour of juvenile Jasus edwardsii reared in captivity

Lobster stock enhancement efforts have generally met with limited success owing, in part, to low survival of reseeded juveniles caused by poor development of anti-predator behaviour. We found that recently-settled juvenile lobsters reared in captivity for 1 year exhibit significantly higher levels of daytime activity than their like-sized wild counterparts and that this daytime activity could be reduced by 50% by either rearing the lobsters with a predator or by feeding them at night. In combination, predator presence and night-time feeding further reduced daytime emergence to low levels. However, a field experiment in which we observed the behaviour and emergence times of captive-reared lobsters immediately after release on reefs where predators were abundant, showed that regardless of rearing conditions and associated changes in behaviour, lobsters assess the risk of predation and quickly assume nocturnal emergence and activity patterns. This plasticity in behaviour may enable juveniles to maximise foraging range and duration in response to predation pressure.