Study for coastal fisheries stock management. I. Selection of target species and operating areas for coastal trawlers.

Abstract

The data used in this paper are catch statistics of coastal trawl fishery in the Sea of Japan off Niigata Prefecture in 1983. The relative fishing power of 15 groups of boats, stratified by the base ports and classes of power of engines, were estimated for each of 4 flatfishes and others by a simple method to compare CPUE's in the same fishing area in the same month from the pair data. The standardized CPUE in each area was calculated. Allocation pattern of fishing power to each species is different among groups and they are separated into three clusters by the cluster analysis. These clusters agreed with similarity among boats in the species composition of catch. The allocation patterns of relative fishing power are related to the stock abundance in their operating areas. Problems in applying the management measures are discussed. The advantages of existence of several clusters for the stock management are: (1) to aviod concentration of effort on a specified stock; (2) to mitigate the competition among fishermen. However, the benefit from a stock management measure would often not be equal among fishermen and this is the disadvantages of the existence of clusters.