Regional patterns in puerulus catches from eastern and western Tasmania

Abstract

Approximately 65% of Tasmania's southern rock lobster Jasus edwardsii catch is taken from the west coast. Fishers from the west coast have reported that many inshore sites that were productive 10 or 15 years ago are no longer productive so that they now receive reduced effort, with effort displaced into other regions. The failure of stocks to recover in these sites despite widespread increase in biomass in the Tasmanian fishery overall suggests that recruitment to the inshore west may be low. This was investigated from puerulus catch monitoring, which has been conducted using crevice collectors at 28 sites around the Tasmanian coast at various periods. Catches at the 8 sites off the west coast (0.24 ± 0.06 mean pueruli per collector per month) have been consistently lower than those from the 18 sites off eastern Tasmania ( 1.68 ± 0.12 mean pueruli per collector per month). This spatial pattern supports the hypothesis that low recruitment to inshore west coast areas results in a population that is not robust to fishing pressure. Regional differences in recruitment point to the need to incorporate spatial components into management of rock lobsters.