Puerulus settlement forecasting in a harvest strategy evaluation of the rock lobster fishery in South Australia

Abstract

Harvest strategies are utilised in the management of fishery resources globally. Critical to their success is harvest strategy evaluation, whereby future performance is assessed through projection modelling. Using the observed relationship between a puerulus settlement index and model-estimated recruitment, we evaluated a southern rock lobster (Jasus edwardsii) harvest strategy in South Australia. Short-to-medium puerulus settlement recruitment forecasting was incorporated into future projections of catch, catch per unit effort, and percent unexploited egg production (%UEP) during 2019–2022. Observed values of indicators that closely aligned with projected outputs indicated that puerulus forecasting underpinned reliable evaluation of future fishery performance. A key objective of the harvest strategy was to increase egg production in the fishery, with a 20% unexploited egg production targeted by 2036. The target was reached under the proposed strategy, but was sensitive to recruitment, thereby highlighting the need to consider climate change impacts in forecasting scenarios.