Effects of age, sex and abundance on the bathymetric pattern of American plaice in the southern Gulf of St Lawrence

American plaice Hippoglossoides platessoides density in September in the southern Gulf of St Lawrence was strongly related to depth, with peak densities at intermediate depths (70–90 m). Bathymetric pattern was similar for all ages of plaice (3–12 + year) and varied little among years. Densities were highest at similar depths for males and females, but depth distribution tended to be more spread out for females. Depth distribution was not significantly density dependent except for 10-and 11-year-old males and for females aged 12 years and older. In the three significant cases, depth distribution tended to spread out as abundance increased. Water temperature and depth were closely linked in the southern Gulf, but plaice depth preferences could not be attributed solely to temperature selection.