TSDV: A GIS tool for inspecting trawl survey data

The aim of this paper is to present a tool for the exploratory analysis of trawl survey data using a Geographical Information System (GIS). In particular, the architecture and the main functions of an interactive desktop mapping system, the Trawl Survey Data Viewer (TSDV), are described. The TSDV was developed to provide non-GIS specialists fishery researchers an intuitive visualization and query mechanism of the spatial data sets produced by trawl surveys. The system is able to readily produce distribution maps by species or groups of species. Moreover, it allows to visualize spatial distributions of abundance data, disaggregated by important population parameters such as length class, sex, and maturity. The rationale of this approach is the importance to investigate the spatial component of some relevant aspects of species biology (spatio-temporal distribution patterns, juvenile and/or nursery areas, spawning areas) and to formulate hypothesis for subsequent analysis. Further work must be conducted in order to develop analytical and statistical confirmatory procedures. (C) 2002 International Council for the Exploration of the Sea.