Fishers have often complained that standard fisheries survey data do not adequately reflect the grounds targeted by commercial fishers and hence scientists tend to make over-cautious estimates of fish abundance. Such criticisms are of particular importance if we are to make a creditable attempt to classify 'Essential Fish Habitat' using existing large-scale standard trawl surveys. Nevertheless, these datasets provide a powerful tool to examine consistent patterns in the temporal abundance of fish on a spatial scale. Here, we report a questionnaire survey of fishers that invited them to indicate the location of grounds of key importance for gadoid fishes. In addition, fishers were asked to indicate whether they had noticed key habitat features that might indicate the characteristics of EFH. A comparison of such areas as highlighted by fishers with data from standard groundfish surveys were broadly compatible for all three species of gadoids examined. Many sampling stations of these surveys fell outside areas highlighted by fishers as key fishing grounds/habitats. Fishers were able to provide usable biological observations that were consistently cross-referenced by several independent sources, for example the occurrence of haddock over brittlestar beds. We conclude that fishers' knowledge is an invaluable supplement to existing datasets that can help to better focus more detailed studies of EFH.