Bathymetric variation in condition and length-at-age of southern Gulf of St. Lawrence cod in September

We describe depth-dependent variation in the condition and length-at-age of southern Gulf of St. Lawrence cod on their feeding grounds in September, 1971-2000. Bathymetric variation in condition appears to be linked to abundance. In periods of low abundance, condition was relatively uniform over shallow (< 50 m) and intermediate depths (<100 m). During periods of high abundance, condition was highest in shallow waters and declined at intermediate depths (50-100 m). In all periods, condition was lowest in deep waters (>100 m). Bathymetric trends in length-at-age contrasted with those in condition. Length-at-age was high in the deep waters where condition was low. Length-at-age also tended to increase from minimum values at intermediate depths to high values in shallow waters. This tendency was most striking in the 1990s, a period when condition was uniform over this depth range. We discuss the ecological, bioenergetic and sampling implications of these patterns.