Logistic model for estimating selection ogives from catches of codends whose ogives overlap

Abstract

An alternative to Beverton and Holt's method of analyzing overlapping selection ogives, which is based on the logistic rather than the normal model, is presented. The principal advantage in using the logistic model is that non-linear least squares estimation procedures are easily applied and the model is therefore applicable to noisy data. Examples are presented from Beverton and Holt, and a mesh selectivity experiment in Puget Sound, Washington.