Exotic fish found for first time
ASHLAND, Wis. - Ice fishing in Chequamegon Bay last winter,
Travis Nye of Ashland hooked a white perch -- the first
one officially documented in the bay -- and set a new
state record, too.
Before Nye's catch, the presence of the exotic fish in
Lake Superior had been confirmed only at the Duluth-Superior
harbor, where it was found in 1986, fishery experts say.
Alan Niebur, a state Department of Natural Resources
regional supervisor, said fishery experts suspect the
white perch -- big enough at 10 5/8 inches and 13.2 ounces
for a state record -- got into the bay through the ballasts
of ships, although migration from elsewhere can't be ruled
Unloaded freighters ensure stability in the ocean by
sucking up water for weight, and then the boats often
release the water, which sometimes carries exotic species,
White perch are not native to the Lake Superior region,
and are found primarily along the north Atlantic coast
near Massachusetts, Maine and Delaware. The fish were
first found in the Great Lakes in 1950, and scientists
theorize the fish moved through the lakes via canals.
Steve Schram, a DNR fisheries biologist, said other exotic
species found in Chequamegon Bay, like the Eurasian ruffe
and spiny water flea, also likely arrived because of ballast
"The problem with all these exotics is we don't
know their long-term ecological consequences," Schram
said. "It may take decades before we start to see
consequences from their introductions."
White perch eat minnows and fish eggs of walleye, white
bass, yellow perch and possibly other species, according
to a publication of the Wisconsin Sea Grant program.
Scientists have blamed the white perch in contributing
to a decline in Lake Michigan's native yellow perch population.
Since their 1988 introduction into Lake Michigan, Niebur
said it's amazing how white perch have populated the warm,
shallow reaches of Green Bay's southern end. Hour-long
trawls of the bay turn up catches that are "almost
all white perch," he said.
The Lake Michigan population crash ended commercial fishing
for yellow perch in the mid-1990s and cut anglers' bag
limits to five per day.
In 1984, the U.S. Geological Survey found a fish in Chequamegon
Bay that one biologist identified as a white bass, but
another said was a white perch, said Gary Czypinski, a
U.S. Fish and Wildlife Service fishery expert.
That specimen was lost, leaving biologists with no way
to confirm the identifications, Czypinski said.