Developing robust approaches to define areas to represent spatial structure of Patagonian toothfish in Heard Island and McDonald Islands (HIMI)

An informed understanding of fish stock structure across spatial and temporal scales with respect to demographics is critical for a robust fishery management approach.  Conceptual models of a fishery stock can help identify spatial or temporal features which can be used to define geographic areas or time frames of interest.  For Patagonian toothfish at Heard Island and McDonald Islands (HIMI), key variables and factors to consider for defining candidate models of stock structure for HIMI toothfish, including water depth, genetic structure, fishing footprint (including gear type and hotspots), tagging density and recapture rate, and toothfish movement patterns. From this review seven spatial area scenarios for stock structure of HIMI toothfish are proposed. Consideration of next steps including movement matrices between spatial areas, statistical approaches that may derive alternative delineation of spatial areas, and consideration of how to undertake comparisons of spatial area scenarios is discussed.