Harvesting Policy under Uncertainty. The Case of the Deep Beaked Redfish in the Irminger Sea

The Deep Stock of Beaked redfish (Sebastes Mentella) in the Irminger Sea is a commercial deep-sea species that mainly inhabits depths between 600 and 900 meters. As is the case for some other deep-sea-species, biological information on the stock is incomplete. While annual catch data is available, only five biomass assessments have been carried out. The stocks mortality is unknown and no firm estimates have been put forth for the carrying capacity. The economic data is as well incomplete. No separate financial statistics exist for the redfish fleet as such. Data on the Icelandic fleet as whole is the most precise, including annual data on revenue. However, there is no data on cost solely due to harvesting of Beaked redfish nor information on effort. A model is presented that takes these data shortcomings into account by adding distributions to number of variables including mortality, carrying capacity, output elasticity of effort and the ratio between the catchability coefficient and marginal variable cost. Given that the model is appropriate it might be used as a gauge for fishery harvesting policies that have a high degree of uncertainty. This holds in spite of the controversial parameters of the model, which are given in distributions instead of values. Finally, the model indicates that the present value of profits yielded by an optimal path of harvest would be between almost the same to 116.5 EUR higher than from an optimal path to the MSY equilibrium. The model further indicates that total allowable catch set by the Northeast Atlantic Fisheries Commission for the next years should be lower if the goal is to maximise the economic performance of the fishery