NANFA-- Aquarium fish and parasites

Brian Haas (
Fri, 31 May 2002 09:53:23 -0500

Another article, and a little more recent. Notice the last paragraph -
perhaps an example of aquarium releases introducing foreign parasites?

see <>
for complete article

March 26, 2002

Study reveals more game fish species at risk from new

MADISON - Laboratory studies show that some of
Wisconsin’s most
popular game fish and a favorite bait fish are
susceptible to infection with
Heterosporis, a parasite first discovered in 2000 in
yellow perch from
the Eagle River chain of lakes in Vilas County.

Rainbow trout, channel catfish and walleye are "very
susceptible" to the
microsporidian parasite, while largemouth bass and
bluegills are
susceptible but not to the same degree, according to
studies recently
conducted by a University of Wisconsin-La Crosse
researcher and
sponsored by the Wisconsin and Minnesota Departments
of Natural

The study also revealed that fathead minnows, a fish
species popularly
used as bait, were very susceptible to the parasite.
Heterosporis doesn’t
pose a human health threat but infects fish muscles
and turns the fillet
white and opaque so that it appears almost as if it’s
been cooked or has
freezer burn.

"But we’re surprised and concerned by what we saw in
the laboratory
about the parasite’s ability to infect other species.
Parasites typically
infect a single species or one group of fish, but
Heterosporis is capable
of infecting fish from several fish families. This
has the potential to infect
more fish in Wisconsin than we previously thought."

The Wisconsin and Minnesota discoveries represent the
documented cases of Heterosporis in freshwater fish
in the Western
Hemisphere, and the world’s first report of the
parasite occurring in wild
fish. Previously, the parasite had been reported in
eels in Japan and
Taiwan and in aquarium fish in France and Germany.
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