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



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

---
MN SEA GRANT NEWS RELEASE
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
Station
near the Bong Bridge on June 25.  While inspecting for zebra mussels, Doug
Jensen, exotic species expert for the University of Minnesota Sea Grant
Program,
and Eric Skadsberg, Plant Manager, collected four of these invasive crayfish
from the screens that guard the plant's water intake pipes.  "Rusty crayfish
are
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
Blatnik
Bridge.  Three native crayfish species were also caught.  During the
crayfish
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.
Live
crayfish taken from a waterbody can only be used as live bait in that same
waterbody, according to Minnesota Department of Natural Resources
regulations.
According to Wisconsin Department of Natural Resources regulations, crayfish
may
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,
and
discard unwanted bait on land.  "Once rusty crayfish gain a foothold there
is no
environmentally friendly way to eradicate them," said Jensen.  "Preventing
the
spread of rusty crayfish and all the other aquatic invaders from the harbor
is
an essential part of protecting our inland waters."

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

A fact sheet describing biology and impacts of rusty crayfish is available
from
Minnesota Sea Grant.  For a free copy of Rusty Crayfish: A Nasty Invader
contact
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
Species
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
Minnesota's
inland waters.



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