ICES Journal of Marine Science, 53: 1063–1078. 1996 Long-term trends in ten non-target North Sea fish species

during the years 1970–1993 are analysed for changes in distribution and abundance by size class. Trends in catch rates of spurdog, starry ray, bib, poor cod, four-bearded rockling, grey gurnard, bullrout, long rough dab, dab, and lemon sole have been compared using correlation and cluster analysis with indices describing diVerent aspects of the North Sea ecosystem, including biomass of pelagic, demersal and industrial species, temperature, eutrophication, and beam trawl eVort. Most species appear to have increased over the period. However, the statistical analysis does not provide a plausible explanation of the factors responsible for the observed changes