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Fight against sea lampreys going well

The tide may be turning in favor of native species in the battle against predatory sea lampreys.

A U.S. Fish and Wildlife Service biologist says there is an "encouraging" sign that measures to eradicate lampreys -- which kill Great Lakes trout and whitefish -- are working.

Native to the North Atlantic, the lampreys have worked their way down the man-made canals in the St. Lawrence River over the last 50 years. They feed by hooking their toothy, disc-shaped mouth onto the sides of fish and essentially eating them from the inside out. The U.S. and Canadian governments first teamed up to fight the infestation in the 1960s.

The invertebrates have been blamed for declining populations of trout and whitefish.

U.S. Fish and Wildlife Service biologist Mike Toohey, who heads the lamprey control program from his Marquette office, said a trap his office set in the Cheboygan River netted fewer lampreys this year than in previous years.

"Either we didn't do as well trapping, or there weren't as many to trap," he told the Traverse City Record-Eagle for a recent story.

Another nearby trap also reported lower than average numbers, he said.

Lampreys are harmless to humans, but will feed on fish of any weight. Recently, Toohey's program has instituted a toxin he calls "Lamprecide." His crew treats rivers that flow in and out of the Great Lakes every three or four years with the chemical.

Bill Swink, a U.S. Geological Service biologist at the Hammond Bay Biological Station, said the program has raised public concern about dumping chemicals into rivers.

The state just spent $12 million re-registering two chemicals in use since the 1960s when standards were different with the Environmental Protection Agency.

"The only reason we have fishing in the Great Lakes is because of the lamprey control program, and that's primarily the lamprecide," Swink said.

Other methods used by the program are catch and release sterilization of male lampreys and low dams called "roadblocks." The dams prevent lampreys from swimming past, but fish such as steelhead and salmon have no problem hopping over. The drawback is that high water levels sometimes allow lampreys access anyway. Electric barriers also are being tested.

Pheromone research is another facet of the program. Toohey said there is a possibility of using synthetic lamprey pheromones to confuse mating lampreys and augment the sterilization program.

Toohey doesn't think anyone would mind if the unsavory looking creatures were gone for good, though total eradication is unlikely. "If they were cute we'd have a very hard time with this program," he said.

  • Sat, 8/17/2002

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