Résumé
The aim of the CATEFA project is to combine information on demersal fish stock abundance from acoustic and bottom trawl surveys. Since acoustic data are collected continuously while the research ship is underway it is likely that combining two sources of information on the same variable should improve abundance estimation. Spatial summaries of the data using a variety of geostatistical models are compared, contrasted and the output described. In this study twenty survey datasets from three areas (North Sea, Irish Sea & Barents Sea) are analyzed. These three zones have diverse species assemblages and hydrographic environments. Nevertheless we manage to find models relevant to most of these different situations. Unfortunately, however, we show that this enhancement can increase the variance of the estimation because of the inherently high variability of acoustic recordings. The purpose of this paper is to compare the results of three geostatistical models (i.e. co-kriging, model with orthogonal residuals, kriging with external drift) in terms of precision, details of maps, variance local and global of the estimation's errors, cross validation and the time series trends of the combining indexes. The role of the acoustic in each model and the precision it brings, is then discussed.