The role of harvest control laws, risk and uncertainty and the precautionary approach in ecosystem-based management.

摘要: The traditional fisheries management approach involves scientists providing their best assessment of the status and productivity a resource. They then use these results to recommend control measure, such as Total Allowable Catch (TAC), based upon some harvest law, which is usually associated with biological reference point (e.g. F0.1). Superficially, Operational Management Procedure (OMP), or equally Strategy Evaluation (MSE), for TAC recommendations may appear identical, this often also links from form law. However, key difference that OMP/MSE simulation testing whole process gives rise recommendation within an adaptive framework. This includes checks application law adopted will not lead major problems, even if perceptions about resource happen be in error; other words, explicit account taken scientific uncertainties, spirit precautionary approach. Furthermore, quantitative evaluations are provided levels catch anticipated medium term, how trade off against risk unintended depletion resource, provide managers readily interpretable basis choose between different options. problems defining risk, have yet resolved. Examples where ecosystem considerations been into extending beyond single-species level can conveniently divided two broad categories, depending on whether they concentrate primarily operational by-catch) predator-prey) interactions species, examples given each. To date, actual practical applications more found cases interactions, particularly area marine mammal by-catch. For involving limiting factor thus far paucity data estimate magnitude predation competition precludes confident computation trade-offs policy options differ extents species. Nevertheless there approximate approaches dealing problem. We approaches, while recognizing limitations, until needed develop reliable models become available. D.S. BUTTERWORTH A.E. PUNT MARAM (Marine Resource Assessment School Aquatic Fishery Sciences Group) Department Mathematics Applied Box 355020 University Cape Town Washington Rondebosch 7701 Seattle, WA 98195-5020 South Africa. USA. 2 role laws, uncertainty ecosystem-based – Butterworth A.E.Punt