There is increasing interest in the use of marine protected areas (MPAs) as tools to achieve the goal of ecosystem management. MPAs could counteract these effects by limiting the impact on areas important for feeding, shelter, spawning and migration. Thus MPAs should include features that enable fish to reach maturity and thus contribute to the spawning stock. But how do we find the most suitable habitats for fish species in large marine areas? Ecological theory (ideal free distribution) suggests that fish will be most abundant in areas that have the most favourable habitat characteristics for that species. Fish stock assessment data could be used to assess where fish species consistently tend to aggregate. In this study we examined stock assessment data collected for three flatfish species (plaice, sole and lemon sole) from 134 stations in the English Channel over nine years. Juvenile fish were excluded from the analysis. The fish abundance data for each year was ranked and the mean rank calculated. The coefficient of variation of the mean rank score had the least variability at stations with the highest mean rank scores and also at those with the lowest rank scores. Stations that had a mid-range mean rank had the greatest inter-annual variation. It would appear that stations with the highest mean rank abundance consistently attract fish. Such areas may be the prime focus for potential MPAs