Estimation of fish density and location using trawl data

Abstract

A concentration of fish can be modelled as a coherent school with definite edges. The purpose of this thesis is to develop such a model to estimate the location of this school and its density. Trawls consist of start and finish coordinates and are of a fixed length. Each trawl makes a catch of fish which depends on the overlap of the trawl into the fish concentration as well as the relative density of the school. Bayesian techniques are used to estimate the location and density of the fish concentration using the observed catch data. Simulated datasets are used to fit circular and elliptical schools and to estimate their densities. Locations and densities of multiple circular and elliptical schools are also estimated by extending the single school model.