1999 Volume 65 Issue 3 Pages 448-454
This paper examines size selectivity in the squid jigging fishery for the oval squid Sepioteuthis lessoniana in Tokushima Prefecture using an extended SELECT model for analyzing size frequency distributions of squid caught by the squid jigging and by set nets. The SELECT model is extended to utilize size frequency distributions constructed from repeat measurements of catch in the squid jig as the test gear and the set nets as the control gear where data on the fishing efforts is not available with variable fishing efficiencies. As a result, size selectivity r(ι) of squid jigs of a body size from 12 to 15cm is expressed as a logistic function of the mantle length ι, r-(ι)=exp(-10.0+0.485ι)/[1+exp (-10.0+0.485ι)]. This equation indicates that oval squid of a size smaller than the jig is not caught by the jig. As the squid attacks the jig as a prey, the size selectivity of the squid jig found here is a type of prey size selectivity.
