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GLIN==> Invasive Crayfish Discovered in St. Louis Bay, MN

Posted on behalf of Deborah Kaminov <dkaminov@d.umn.edu>

DATE: 7/8/99
CONTACT: Doug Jensen
PHONE: (218) 726-8712

Invasive Crayfish Discovered in St. Louis Bay

Rusty crayfish (Orconectes rusticus) were found for the first time in the
Duluth-Superior harbor at Minnesota Power's M. L. Hibbard Steam Electric
near the Bong Bridge on June 25.  While inspecting for zebra mussels, Doug
Jensen, exotic species expert for the University of Minnesota Sea Grant
and Eric Skadsberg, Plant Manager, collected four of these invasive crayfish
from the screens that guard the plant's water intake pipes.  "Rusty crayfish
aggressive, displace native crayfish, and can clear-cut aquatic plant beds,"
said Jensen.  "They can grow quickly, avoid fish predation, and are known to
chase fish from nests then eat the eggs."

Minnesota Sea Grant staff responded by sampling 80 locations throughout the
harbor and up to the Fond du Lac Dam to gauge the extent of the infestation.
Based on the trapping efforts, rusty crayfish are also present near the
Bridge.  Three native crayfish species were also caught.  During the
survey, Minnesota Sea Grant staff also caught nine species of fish, of which
three (round goby, ruffe, and threespine stickleback) are invasive exotics.

Selling live crayfish for bait or aquarium use is illegal in Minnesota.
crayfish taken from a waterbody can only be used as live bait in that same
waterbody, according to Minnesota Department of Natural Resources
According to Wisconsin Department of Natural Resources regulations, crayfish
only be used as live bait in the Mississippi River and the Great Lakes.

Jensen believes we can prevent or slow the spread of rusty crayfish through
education.  He urges everyone not to transport or release crayfish.  Boaters
should avoid transporting aquatic plants, drain water from boats and motors,
discard unwanted bait on land.  "Once rusty crayfish gain a foothold there
is no
environmentally friendly way to eradicate them," said Jensen.  "Preventing
spread of rusty crayfish and all the other aquatic invaders from the harbor
an essential part of protecting our inland waters."

Rusty crayfish have been found in at least 41 lakes and rivers in Minnesota.
the Arrowhead region, they have been found in 15 locations in St. Louis
including: Bass Lake, Birch Lake, Eagles Nest 1, 2, 3, 4, East Vermilion,
Esquagama Lake, Little Long Lake, Rock Pond, Shagawa Lake, Shagawa River,
Lake and Vermilion Lake.  They have been reported from eight locations in
County including: Basswood Lake, Fall Lake, Moose Lake, Newfound Lake,
Lake, Skull Lake, Sucker Lake, and Triangle Lake.  In Cook County, they have
been found in the Pigeon River and Lake Superior.

Rusty crayfish are native to the Ohio River Basin.  This pest may have
spread to
Minnesota through ballast water discharge, live bait use by non-resident
anglers, and releases by students or teachers after studying crayfish
from a biological supply house.

A fact sheet describing biology and impacts of rusty crayfish is available
Minnesota Sea Grant.  For a free copy of Rusty Crayfish: A Nasty Invader
Minnesota Sea Grant at 218/729-6191 or visit our Web site at
www.d.umn.edu/seagr/.  For more information contact Doug Jensen, Exotic
Information Center Coordinator, at 218/726-8712 or djensen1@d.umn.edu.

Minnesota Sea Grant is a federally and state funded program that supports
research and public education programs related to Lake Superior and
inland waters.

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