Study on coastal fisheries stock management. II. Relationship between operating areas and horse power of engines of coastal fishing boats.

Abstract

The power of engines is an important factor for both catching operation and economics of a boat. The speed of boat, the relative fishing power and v1arious costs are assumed to be linear functions of the power of engine or the cube root of it. From these equations, the inequality is derived to divide the profitable and unprofitable domains of the abundance of fishing area and its range from the base port for various power of engine. The two different types of the dependency of the domain on the power of engine are shown. If the power of engine is not so influencial on the fishing power, then low powered boats are fitted to short distance areas whereas high powered boats are adapted to long distance areas. Otherwise, high powered boats are always profitable regardless of the distance. This model is applied to the data of a coastal trawl fishery operating in the Sea of Japan off Niigata Prefecture. The results show that latter type of the domain is applied to this fishery. The assumptions underlying this model are discussed.