Coronary Disease in Spawning Steelhead Trout Salmo gairdnerii.

Coronary degeneration was absent in young trout taken in fresh water and rare in immature fish at sea, but the incidence and severity were sharply greater in migrating fish and almost uniformly present in spawning fish. Several fish taken after they had reentered salt water after spawning had no lesions; lesions in fish taken during their second spawning migration were not cumulative. These facts suggest that the process is reversible.