White Blemishes in Salmon Meat are Tiny Parasites

Salmon fishing runs the range of recreational activity, profession, and means of subsistence in Alaska.  With the silver salmon returning to Northern Valley streams,  many anglers are taking to the rivers in the hopes of bringing home a fish or two.  As with all animals, however, salmon are subject to a number of diseases and parasites.  One of the more common fish maladies comes from a tiny parasite called Henneguya (HEN-uh-GUY-ah) salminicola (sal-MIN-i-CO-la).

Silver salmon are the most commonly afflicted with the parasite, and an infected fish will have a number of white spots in its flesh.  Ted Meyers, Principal Fish Pathologist for the Alaska Department of Fish and Game, says that each of those spots can contain thousands of tiny organisms.  Meyers says that the parasite uses two hosts during its life cycle.  A spawning salmon releases spores into the water, where they infect a first host.  After the eggs hatch and the salmon smolt begin their trip back to the Pacific Ocean, the host organisms release a second set of spores that then infect the young salmon.  The parasite then develops and reproduces inside the fish.  When the mature salmon return to their spawning streams, they release spores and the process begins again.

Meyers says that although the white spots in an infected salmon’s meat are unsightly, and can make the fish difficult to freeze, that the salminicola parasite can only live in a cold-blooded animal, and is harmless to humans and bears.