Abstract
Fish skin contains a variety of humoral defence lysins which have an integral role in fish immunity because of the ability of these proteins to destroy invading substances ( Alexander & Ingram 1992 ). These lysins generally comprise bacteriolysins, proteolysins and haemolysins. The lysins seem to be either individually or cooperatively stimulated to respond to pathogenic infection and environmental stress, such as ionic, osmotic, thermal and pollution stress ( Shephard 1994 ; Rice, Kergosien & Adams 1996 ; Bly, Quiniou & Clem 1997 ). There have only been a few reports on these lysins ( Al‐Hassan, Thomson, Ali & Criddle 1987 ; Aranishi, Mano, Nakane & Hirose 1998 ). The present paper describes thermal effects on defence lysis, such as proteolysis, bacteriolysis and haemolysis, in the skin of the European eel, Anguilla anguilla L.