Abstract
A series of light-luring fishing trials, 84 hauls for 20 days, were conducted bya commercial vessel off the west coast in the Gulf of Thailand using a stick-held cast net from March 1991-February 1992. The mean catches were approximately constant, about 16kg/haul, in a range of light-luring times from 1.5h to 5.5h. When haul by haul catches decreased, it was clearly shown that the larger squid in a shoal were captured preferentially. However, there did not appear to be any considerable changes in the size structures of squid caught by successive hauls, when haul by haul catches increased or decreased. The number of squid aggregated into the lit area was estimated to be about 1, 000-3, 000. The efficiency of the cast net may be a function of the number of squid, or in other words, a low catch efficiency might be caused mainly by dispersion of shoals at low density or by gear aturation at high density.
