Surviving a sea-change: survival of southern rock lobster (Jasus edwardsii) translocated to a site of fast growth

In an experiment aimed at increasing the yield and value of the fishery for southern rock lobster (jasus edwardsii), 1998 pale and slow- growing lobsters were translocated to sites where lobsters grow faster naturally and develop higher value market traits. Survival of lobsters in their new habitat was critical to the viability of this experiment. To estimate survival, the release site was surveyed every 1-3 months for 2 years. Apparent survival of translocated lobsters was compared with survival of resident lobsters tagged in a similar period using Cormack-Jolly-Seber modelling on mark-recapture data. Lobster survival was not influenced by size, gender, or origin (translocated or resident) alone. The four most parsimonious models suggested slightly lower apparent survival in translocated lobsters immediately after release compared with all other lobsters, but support for these models was weak (QAIC weights 62%). The differences in apparent survival were not likely to be significant because of large variance when averaged over all the models. Apparent survival of newly released translocated lobsters was 92% (72-98, 95% CI) compared with 97% (95-98, 95% CI) for all other lobsters. Potential sources of differences in survival are movement from the release site or greater predation on pale lobsters. Losses of lobster through release mortality were low and unlikely to influence the feasibility of translocation as a tool to enhance the value of the fishery, although it would be prudent to include 5% mortality of translocated lobsters in future models of translocation feasibility.