Simulation of Fishermen's Selection of Fishing Areas for Stock Management

Abstract

This paper proposes a simulation model on the selection of fishing areas for groups of coastal fishermen under the condition of the competition principle for the sake of examining the effectiveness of stock management. Principal assumptions are that fishermen have sufficient knowledge of the geographic distributions of stock abundance and that biological parameters are constant. The geographic distributions of effort are simulated by repeating the following two calculations. The first is that the effort of the groups are distributed according to the rule that fishermen operate in the most profitable area, by using the theoretical CPUE in value and cost. The second is that decreases of stock size in areas for the mortality are calculated by Beverton and Holt's model. Fishing mortality coefficient, stock sizes and catch are calculated after the simulation. This model is applied to the data of a coastal trawl fisheries that mainly catches flatfish. From the results, the value of the correlation coefficient between the data and the result of simulation for annual number of hauls is 0.752 (significant at 5% level). Furthermore, the effectiveness of some stock managements are compared from the applications of the model. The factors related to the fishermen's selection and the modifications of the model are discussed.