Mapping dei dati delle campagne sperimentali di pesca

Trawl surveys generally produce a huge amount of data, for several reasons: o the time frequency of the surveys; o the geographical size of the study area; o the number of hauls carried out in the area; o the number of parameters collected during each haul; o the number of species identified; o the number of parameters collected for each species. This great abundance of data is generally processed by means of tools which do not consider the geographical position of the datum but produce synthetic and statistical information which is geographically not-correlated. The application developed is based on a GIS and is aimed at storing, managing and analysing the trawl survey data in their spatial context. It includes a set of functions which allow the user to work dynamically on the database by interactively selecting the surveys, the hauls, the various species and their parameters (length, sex, sexual maturity). For each selection performed by the user, it produces synthetic and high level information, both in a table and graphically. It can be considered as a tool for the preliminary analysis of data collected. Its results represent a consistent starting point for a study aimed at analysing the distribution, the abundance and the population dynamics of demersal species which are the target of commercial fisheries. The application (developed in the context of the activities within the FIGIS project of the European Community) uses data collected during the trawl surveys carried out in the Gulf of Castellammare (Sicily) in 1993-94, nevertheless it can be generalized so as to manage time series of trawl survey data relative to any geographical area.