Implications of trip regulations for high-grading: a model of the behaviour of fishermen

This study developed a simulation model, based on observations of the actions of fishermen, to determine how regulations on trips by management agencies may influence discarding behaviour at sea. The model employed the results of a separate dynamic optimization model and data from the Oregon groundfish trawl fishery to predict quantitative patterns of high-grading expected across a range of regulatory limits on both fishing effort and the quantity of landings per trip (trip quota). High -grading was predicted to be greateest when there is a high probability of the catch exceeding the trip quotas, as when effort limits are high and trip quotas are low. The evaluation of regulations also considered indicators such as expected economic value of the trip, proportion of trip landing limit attained, and the number of trips made in a season. A combination of large trip landing limits and intermediate trip effort limits best satisfied the multiple goals typically used by management agencies. -from Authors