Introduction of spatial management in a temperate abalone (genus Haliotis) fishery: What can be learned from spatial variability in catches?

Abstract

AbstractExploited abalone (genus Haliotis) populations are prone to serial depletion and stock collapse. Spatial management units (MUs) aim to separate monitoring and management of meta‐populations with varying productivity. In the South Australian Southern Zone blacklip abalone (Haliotis rubra rubra, Leach) fishery, spatial terms at scales of kilometres (reporting areas, RAs) and tens of kilometres (MUs) explained a greater proportion of variability in daily catches than effort in linear mixed models. Temporal patterns in spatial structures of catches among RAs were consistent with those among MUs based on similar productivity. Results of this study support the hypothesis that changes in the spatial distribution of catches differs among management regimes based on minimum legal lengths (MLLs) and annual total allowable commercial catches (TACCs). Stable distribution of catches during 1992–2012 occurred contemporaneously with zonal TACCs combined with catch caps (sub‐TACCs) and MLLs applied to areas of low productivity providing a reference for future management. The number of MUs fished annually by each licence increased during this period. Results of this study suggest that successful spatial management of abalone fisheries requires MUs at scales based on biological productivity combined with MLLs and mandatory, conservative catch caps applied to each MU.