A cephalopod fishery GIS for the Northeast Atlantic: development and application

Cephalopod stocks are of increasing economic importance. Cephalopod fisheri es show marked inter-annual fluctuations unrelated to fishery landings and effort. Their population dynamics, particularly recruitment, are thought to be strongly susceptible to changes in environmental conditions. This arise s in part from the short life cycle, resulting in poor buffering of the pop ulation against changing conditions. These characteristics make traditional approaches to stock assessment and fishery management inappropriate. GIS o ffers a tool to improve understanding of spatio-temporal trends in abundanc e and facilitate rational management. A cephalopod fishery geographical inf ormation system for Northeast Atlantic waters (CFGIS-NEA) was developed. Th e system covers the area from 28.0 degrees W to 11.0 degrees E, and 34.5 de grees N to 65.5 degrees N. It was designed for investigating cephalopod res ource dynamics in relation to environmental variation. It is based on Unix Arc/Info, and PC ArcView, combined with the statistical software package S- PLUS and supported by a database in Microsoft Access. Environmental data (e .g. sea surface temperature and salinity, sea bottom temperature and salini ty, and bathymetric data), cephalopod fishery, survey and biological data, from a variety of sources, were integrated in the GIS as coverages, grids, shapefiles, and tables. Special functions were developed for data integrati on, data conversion, query, visualisation, analysis and management. User-fr iendly interfaces were developed allowing relatively inexperienced users to operate the system. The spatial and temporal distribution patterns of ceph alopod abundance by species, the spatial and temporal relationships between cephalopod abundance and environmental factors, and the spatial and tempor al patterns of cephalopod fishing activity were analysed using a combinatio n of visual (qualitative) and quantitative methods. Predictive empirical mo dels, such as GAMs (generalized additive models), were developed for modell ing cephalopod abundance using environmental variables.