Experimental Infection of Atlantic Cod with a Larval Marine Nematode from Smelt

Abstract

Atlantic cod (Gadus callarias) and at least 13 other species of fish in Canadian Atlantic waters are intermediate hosts for a larval nematode (Porrocaecum decipiens). It is pointed out that large cod feed occasionally on infected species of fish and that, as a result, they may become infected. Experiments showed that when larval Porrocaecum from smelt (Osmerus mordax) were fed to cod, some worms passed through the wall of the stomach, crossed the coelom, and penetrated the hypaxonic muscle of the cod. It was concluded that Porrocaecum larvae, under natural conditions, are also able to pass from one species of fish to another.