Publication Abstract

Modelling fishermen's behaviour within mixed fisheries

T. Hutton, S. Mardle and S. Pascoe

Numerous studies have proposed methodology to model fishermen’s behaviour in order to predict the outcomes of the decision-making process on board a fishing vessel. Decisions on investment that impact on the longer-term economic variability of the production unit have also been considered. Both short- and long-term processes impact on fleet dynamics. These models could be included within the framework of a full-feedback fisheries systems evaluation that normally includes an operating model, a model of the assessment process and harvest control rules. This would allow for an analysis of the benefits of including any model of fishermen’s behaviour. Within the context of multi-stock, multi-fleet fisheries (mixed fisheries), a skipper will allocate effort (as an input to the production process) in order to harvest species (A, B, …) whereas the regulations within a single-species TAC system (quota restrictions on species (A, B, ..) result in high-grading and discarding that are not included in the assessment models. The complexity of models that have been proposed depends on the nature of the fishery (state variables) and the control variables (that allow for the choice of modelling the effects of for example, quota restrictions, effort control and/or closed areas). Furthermore, short-term versus long-term decisions can be included. In addition, a choice can be made whether to include factors that are endogenous or exogenous to certain variables, such as the impact of the market on prices, quota, labour and capital. We explore the minimum requirements of these behaviour models within the context of mixed fisheries, as well as the assumptions made, and consider the options available for modelling such a process under data-rich and data-poor situations.

Reference:

T. Hutton, S. Mardle and S. Pascoe, 2003. Modelling fishermen's behaviour within mixed fisheries. ICES CM 2003/V: 16. ICES Copenhagen.