IMPLICATIONS OF TRIP REGULATIONS FOR HIGH GRADING - A MODEL OF THE BEHAVIOR OF FISHERMEN

We developed a simulation model, based on observations of the actions of fishermen, to determine how regulations on trips by management agencies may influence discarding behavior at sea. Our 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). In all cases, the total seasonal landings were assumed to be constant. High-grading was predicted to be greatest when there is a high probability of the catch exceeding the trip quotas, as when effort limits are high and trip quotas are low. Our 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.