Asian Tapeworm outbreak in Great Lakes

12/22/08 by Jeff Alexander | Muskegon Chronicle

An outbreak of tapeworms in Lake Huron walleye has Michigan officials
urging people to avoid eating sushi made with freshwater fish caught in
the Great Lakes region.

The warning came as a Canadian researcher reported the first documented
case of Asian fish tapeworms in Great Lakes fish.

David Marcogliese, a research scientist at Environment Canada's research
station in Montreal, reported the discovery of Asian tapeworms in Lake
Huron walleye in the most recent issue of the Journal of Great Lakes
Research.

The foreign tapeworm, the 186th invasive species documented in the Great
Lakes, likely was imported to the region with infected bait fish,
Marcogliese said in the article.

"This parasite is known to cause weight loss, anemia and mortality in
young fishes," Marcogliese said.

Numerous anglers began reporting finding tapeworms in walleye caught in
Lake Huron and Saginaw Bay, according to a Michigan Department of
Natural Resources memo. Fish from some inland Michigan lakes also were
infected with tapeworms, according to the DNR memo.

Some species of tapeworms are native to the Great Lakes fish. The
discovery and proliferation of Asian fish tapeworms is a recent
phenomenon that could harm walleye and other fish species, according to
DNR officials and Marcogliese's research.

Researchers indicated the Asian fish tapeworm, one of the world's most
pernicious invaders, will likely spread across the Great Lakes region.
The tapeworm can grow to one-foot-long in large fish, such as carp,
Marcogliese said.

DNR officials said it is safe to eat fish that have tapeworms, provided
the fish are thoroughly cooked, smoked or pickled using normal food
preparation techniques.

"We do not recommend making sushi from any species of freshwater fish as
the risk to humans is not known," according to the DNR memo. "It is a
very bad idea to eat any freshwater fish raw or poorly cooked as fish
parasites use fish-eating mammals and birds as hosts and it is not known
if humans can also be hosts."

Tapeworms are ubiquitous in waters where fish live, but the incidence of
the parasites infecting fish has surged in the past two years, according
to DNR officials. State officials said the problem may be due to changes
at the base of the Great Lakes food chain caused by zebra and quagga
mussels, two other invasive species.

Asian fish tapeworms were carried into the U.S. in the 1960s by federal
officials who imported Asian carp to control algae in Arkansas fish
ponds. The invader has since spread to lakes and rivers across much of
North America, according to federal records.

The invasive tapeworms enter the fish food chain when zooplankton ingest
the creatures and become hosts for the parasite. The tapeworms move up
the food chain as zooplankton are eaten by small fish; the pests mature
and produce eggs once in the intestinal tracts of walleye and other fish
species.

Fish excrete tapeworm eggs in their feces. The eggs settle on lake
bottoms, where zooplankton eat them and give rise to a new generation of
the pests.

The mere sight of tapeworms can tarnish a fishing trip -- the creatures
are known to slither out of the mouths and gills of dead fish.

To avoid finding a tapeworm in your fish cooler, DNR officials recommend
gutting fish immediately after catching them and disposing of the
entrails after returning to land. It is illegal to discard fish guts in
Michigan waters.

interesting article... thanks for posting

Thanks for posting. It's not uncommon to find tapeworms in fish already. I had a batch of White Bass that I plucked from the nearby Maumee River (a direct tributary to Lake Erie). Those fish were on display for about a month, and although they ate well, they never gained much weight. A biopsy on one later revealed a heavy infestation of tapeworms. So, they're probably in the aquarium now (the tapeworms), as I actually witnessed one of my fish "passing one" one time. It's unfortunate that we now have an invasive tapeworm to deal with as well in the Great Lakes region.

I apologize to az9 and the group for double posting this article.