Invasive fish species found in Lake
Champlain, say experts from Quebec, Vermont
CANOE News (http://cnews.canoe.ca)
Published November 10, 2005
GRAND ISLE, Vt. (AP) - Biologists from Vermont and Quebec
have discovered an invasive fish species living in Lake
Champlain that threatens to change the lake's ecosystem.
Alewives, a member of the herring or "shad"
family, could displace smelt as the primary forage fish
in the lake and could reduce the populations of other
lake fish. "An alewife invasion could potentially
cause significant ecological and economic disruption in
Lake Champlain," said Dave Tilton, director of the
U.S. Fish and Wildlife Service's Lake Champlain complex.
Alewives have been found over the past three years in
samples taken throughout Lake Champlain done by state,
provincial and federal agencies.
The first alewife was found in 2003 by biologists from
the Quebec Ministry of Wildlife and Parks. A single adult
alewife was found in northern Lake Champlain in 2004 by
Vermont Fish & Wildlife Department biologists.
As a result of those discoveries, co-ordinated sampling
efforts were expanded throughout Lake Champlain this year
by the Vermont Fish & Wildlife Department and the
U.S. Fish & Wildlife Service and additional fish were
Vermont fisheries biologist Bernie Pientka said he believed
the catches indicated a new population may be forming
in Lake Champlain.
"The collection of both juvenile and adult individuals
from different areas of Champlain suggests that alewives
are now reproducing in the lake," said Pientka.
Alewives are native to the Atlantic Ocean but migrate
to freshwater rivers and lakes to spawn. They are able
to adapt to live their entire lives in freshwater and
have done so in the Great Lakes and many other inland
waters across the country.
In some areas, they are used as bait and have become
established in many lakes following intentional introductions
or accidental releases from bait buckets.
"Alewives restructure a lake's food web, leaving
less food for native fish. They can also eat a lot of
young fish, such as newly hatched perch, walleye and lake
trout," said Vermont fisheries biologist Shawn Good,
who wrote a report last year about the potential impact
of alewives in the lake.
The presence of alewives in Lake Champlain could cause
declines in the Lake Champlain populations of species
such as cisco, whitefish, shiners, and yellow perch.
And a diet of alewives can cause a disease in salmon
and lake trout.
The Lake Champlain Basin Program is sponsoring a workshop
this winter where experts can discuss what to do.