Modeling the spatial dynamics of the US purse-seine fleet operating in thewestern Pacific tuna fishery

Two qualitative choice models of the location decisions of U.S. purse-seine vessels operating in a total of sixty-five 5 degrees grids in the western Pacific tuna fishery are developed and compared. A nested legit model in wh ich decisions are first made about where to fish in the east-west plane, fo llowed by a choice of grid in the north-south plane, performs better than a nonnested model in which all grids are considered simultaneously. The nest ed model can be used for the allocation of purse-seine fishery effort in a spatially disaggregated bioeconomic model of the regional tuna fishery.