Distribution pattern of groundfishes hooked along a row of setline in the shallower part of the continental slope in the Bering Sea 2 bathymetric difference in relative abundance in relation to distribution pattern

Abstract

Summary and Conclusion This report demonstrates the well‐defined bathymetric distribution of relative abundance of groundfishes in relation to the distribution pattern conjectured from the records of catch along a row of setline with remarkably large variation in the settled depth (from shallower than 350 m to deeper than 700 m) observed around 580 18′ N and 1750 28′ W on Aug. 24, 1962. The results of the analyses are depicted in Fig. 1. It is found that halibut, true cod and Sebastodes sp. (or Menuke in Japanese) show sharp or abrupt decrease in the relative abundance in accordance with depth whereas sablefish and rattail increase sharply. Arrow toothed halibut and ray do not show any clear bathymetric change in relative abundance and Pacific ocean perch shows decrease in the density in accordance with the disparity in the depth from the 500 m isobath. The patterns conjectured from this example are compared with either those shown in other reports, the results of the observations on other examples or general view of our fishermen. And many proofs to the high reliability and wide universality of the conjectured pattern of the first four species are found out. But, for the last three species, the present results differ more or less from the general view of our fishermen and the observations on other examples. For the distribution pattern, most of groundfishes incline to show chance distribution in the shallower part of the continental slope (350 m to 700 m deep) and only the species showing sharp decrease in density with increase in the depth are distributed contagiously on the shallower bottom (not deeper than 450 m).