Great Lakes Article:

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 found.

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.