mussels can't take the cold
Or the lack of calcium in Chequamegon Bay
By Claudia Curran
The Daily Press
It appears that zebra mussels accidentally introduced
into Chequamegon Bay in 1998 haven't been able to survive
and reproduce, judging from recent zebra mussel survey
Mild winters in 1998, 1999 and 2000 influenced a blossoming
of zebra mussels in the Duluth-Superior harbor, but those
same winters haven't seemed to affect Chequamegon Bay,
said Gary Czypinski, U.S. Fish and Wildlife Service biologist
and fishery technician.
The primary reason for the absence of the mussel may
"We think it's due to a lack of calcium in the water,"
Czypinski said, adding that cold-water temperatures might
also be a factor.
One of the first times Czypinski heard of zebra mussels
being sighted in Chequamegon Bay was from an angler who
fished off of Ashland's ore dock and snagged a piece of
wood with a clump of zebra mussels attached.
Before the angler made the report, a zebra mussel-infested
barge from Michigan came into Chequamegon Bay in 1998
- accidentally introducing several hundred exotic mussels
into area waters, according to a report of the U.S. Fish
and Wildlife Service's Ashland Fisheries Resource Office.
The Chequamegon Bay Zebra Mussel Task Force has monitored
waters around the Bayfield Peninsula for the exotic mussel
Only one dead adult mussel was sighted during a 2001
task force survey.
The mussel, found near an Ashland waterfront park boat
landing and close to the Xcel Energy waterfront plant
discharge area, could have fallen off of a boat's hull
and into the water, and therefore may not be a juvenile
from reproducing mussels in Lake Superior.
"There's no evidence of reproduction," Czypinski
Initial surveys of the four-year taskforce monitoring
effort required the use of monitoring devices set near
Madeline Island, in Chequamegon Bay, and close to shore
from Sand River to Bad River - the equivalent distance
of more than 100 km.
Plankton tows were also done to look for mussels in the
Last year's zebra mussel survey depended on the efforts
of divers who inspected the power plant and an Ashland
This year Czypinski expects the divers to inspect the
Ashland marina and the Ashland ore dock over a three-day
stint sometime this summer.
Although divers are more expensive than monitoring devices,
they're less labor intensive and a more effective way
of looking for the exotics, Czypinski said.
Are native to Balkan region of Poland and the former
Have striped shells, grow to about 50 mm long, and live
from four to five years.
Crawl on lake bottoms with a foot and then usually attach
to something hard or rocky.
Filter feed and primarily eat algae.
Can stay alive for several days out of water, depending
Were likely introduced to the region through ocean freighter
ballast water dumps in the Great Lakes and moved from
place to place by attaching to boats and barges.
Are notorious for colonizing water supply pipes of hydroelectric
and nuclear power plants, public water supply plants and
industrial facilities. In the pipes, the mussels constrict
flow and reduce intakes of mechanical systems.
Cause drag on boats they've attached to and can damage
engine cooling systems.
Are known to have sunk buoys, fouled fishing gear, deteriorated
dock pilings and corroded steel and concrete.
Adapted from U.S. Geological Survey
Prevent the spread of zebra mussels
After boating remove visible vegetation from the boat,
propeller, trailer and other equipment.
Flush the engine cooling system, live wells and bilge
with hot water. Rinse other areas that may be wet.
Air dry the boat for five days before using it in uninfested
Inspect the outside of the boat if docked in infested
waters. If your gear or the boat feels gritty, young microscopic
mussels may be attached.
Do not re-use bait and don't release live bait.
Adapted from Ohio Sea Grant