Numbers of co-occurrences of 29 common fishes of the Bay of Fundy and Scotian Shelf were derived from annual research trawl survey data for the summers of 1970–79 and the spring, summer, and autumn seasons of 1980–84. Matrices prepared from the data were used to examine degrees of association between different species and seasonal and geographical variation in the associations. Three categories of associations were identified: shallow water with a dominant winter flounder (or yellowtail flounder) – longhorn sculpin – sea raven assemblage; middepth with a dominant cod – haddock – thorny skate assemblage; deepwater characteristic species but with no strong recurring assemblages. Strength of co-occurrence was directly related to species abundance and changes corresponded to known seasonal movements in several species, including silver hake, spiny dogfish, and pollock. In general, the strength and number of co-occurrences decreased from southwest to northeast along the Scotian Shelf. The Bay of Fundy was exceptional, with strong co-occurrences of shallow-water species and poor representation of deepwater fishes.