Reflecting on 25 years of quota management in a spiny lobster fishery: Lessons learned from a harvest strategy perspective

The Southern Zone rock lobster fishery of South Australia has been managed by individual transferable quotas since 1993, with annual catch limits set using harvest strategy decision rules. This work describes the performance of strategies over 25 years focusing on challenges experienced during periods of poor fishery recruitment. Early strategies identified indicators and performance ranges for the fishery but lacked detail on required management action when reference points were breached. Between 2002 and 2009, the fishery experienced a considerable decline in recruitment resulting in catch rate, the primary indicator, decreasing by 70%. The harvest strategy in place failed to reduce catch levels appropriately and despite consecutive years of decreasing catch rate, was unable to arrest the fishery decline. Explicit harvest control rules for quota setting were developed in 2010 and refined in both 2014 and 2019, with the specific focus of ensuring sustainability and rebuilding lobster biomass. Application of these strategies have been successful at achieving this objective, most notably since 2015. The study highlights that harvest strategies must include control rules that respond rapidly to recruitment declines. Specifically, based on harvest strategy testing and evaluation, required levels of quota reduction should be clearly defined. In combination with limit reference points that mandate the point of fishery closure, metarules and quota caps that promote biomass increase, such strategies serve to meet fishery objectives and ensure sustainability.