Management strategy evaluation for rock lobster,Jasus edwardsii, off Victoria, Australia: Accounting for uncertainty in stock structure

Abstract

The management strategy evaluation (MSE) approach was used to evaluate management strategies based on the current method of stock assessment for rock lobster (Jasus edwardsii) off Victoria, Australia, and decision rules inferred from the management plan for Victorian rock lobster and past practice when selecting total allowable catches, TACs. The results are expressed in terms of whether it is possible to keep stocks above limit reference points with high probability and recover overexploited stocks to the target level. Three categories of management strategy were examined using the MSE, which differed in whether assessments were conducted, and TACs set, by management zone or by region within management zone. A management strategy based on conducting assessments and setting TACs by management zone is most similar to the way assessments are currently conducted and management regulations implemented for rock lobster off Victoria. However, this management strategy performed poorest in recovering stocks to target levels. Alternative management strategies which involved conducting assessments and setting TACs by region performed better, but may have practical limitations. The assessment method was found to be generally relatively accurate and precise, although estimation performance was poor/imprecise on occasion.

Why model assumptions matter for natural resource management: interactions between model structure and life histories in fishery models

“…There are a number of empirical studies specifically designed to examine the implications of stock structure uncertainty (IWC 1994;Dichmont et al 2006;Kell et al 2009;Punt & Hobday 2009), and while none have considered explicit economic implications, the work contained in this paper adds to the research that ignoring spatial structureboth demographic and fishery relatedcan have a profound impact. We found that the assumptions made about stock structure not only resulted in different bioeconomic TRPs (generally, smaller steady-state effort from the multistock models) but also different economic outcomes, although little evidence of differences in conservation-related outcomes was found.…”

Management strategy evaluation: best practices

“…For example, although Butterworth and Punt () commented that there were very few operating models which accounted for spatial structure when they conducted their review in 1998, subsequently Punt et al . (), IWC (,b, , ), Punt and Hobday () and Carruthers et al . () have all developed operating models which can, to some extent, account for spatial structure.…”

Using ecological indicators in the context of an ecosystem approach to fisheries for data-limited fisheries

“…In the development of management strategies, management strategy evaluation (MSE) is often used to evaluate the potential different strategies that can influence the states of fish resources and their corresponding fisheries (Punt and Hobday, 2009). The MSE simulates the behaviour of fish stocks and fishing fleets and provides the ability to forecast, with estimates of the associated uncertainty, changes in the states of the fish stock and its fishery as a consequence of management scenarios.…”