Differences observed in autoradiogram profiles and isotope ratios or corticosteroid metabolites (such as cortisol), in vitro, in interrenal activity between and within hatchery reared salmon (Salmo salar) parr stocks were not observed in corresponding wild stocks. Wild fish from nine Nova Scotian rivers (Annapolis, Black, East, Gold, LaHave, Medway, Musha-mush, Salmon, and Stewiacke Rivers), sampled during May to December all showed similar corticosteroid profiles. Differences were observed in corticosteroid profiles in December between: (1) hatchery stock held in acidic and circumneutral rivers; and (2) hatchery stock held in cages in a limed river, wild stock from this river, and hatchery stock maintained at the hatchery. Copyright 1994, 1999 Academic Press