Mortalities of <i>Salmo gairdneri</i> exposed to cultures of <i>Gyrodinium aureolum</i>

Abstract

Rainbow trout were exposed to five different concentrations of a unialgal culture of Gyrodinium aureolum in laboratory tanks. All the concentrations used proved lethal within 24 h. The gills of the dead fish showed no mechanical occlusion by the algae but all displayed marked histological changes characterized by necrotic degeneration and disintegration of the lamellar epithelium.