Management of Multiple Objectives

The advice framework of the International Commission for the Conservation of Atlantic Tunas (ICCAT) is based on achieving Maximum Sustainable Yield (MSY) for each target species. However, fisheries catch a mix of target and non-target species and fishing is an economic activity. This means that managers need to consider economic as well as biological factors when deciding between management options. For example evaluating a closed area requires knowledge of where the effort will be displaced to and consequences for catch rates of target and non-target species and fishing costs. To do this we use individual vessels data to determine how fishers allocate fishing effort; assuming that the utility of fishing in an area depends on previous catch rates, revenue and the costs of fishing. The model can be used to estimate where effort will be re-distributed; allowing multiple management objectives and the trade-offs between them to be evaluated, e.g. impacts on target and non-target species and profitability to be calculated. Thereby helping to develop a coherent framework for strategic planning and management and provide a better understanding of how economic factors affect targeting and catch per unit effort series used as proxies of stock abundance.