A silvery, 6-inch fish made grown men groan Thursday. State fisheries biologists announced that the alewife, a nuisance fish that has plagued the Great Lakes, appears to have established itself in Lake Champlain.
"This is not something any of us wanted to see," said angler Dan Mitchell of Swanton, president of the Lake Champlain Walleye Association. His group has labored for more than 20 years to re-establish a healthy walleye population in the lake.
Alewives, native to the Atlantic Ocean, become an invasive species when they establish a year-round population in freshwater lakes, where they can drive serious, negative changes in the ecosystem.
They don't make good food for humans, but are voracious, effective feeders themselves. They are likely to outcompete smelt, the dominant forage fish in Lake Champlain, and the young of walleye and yellow perch. They also eat young perch and lake trout.
Alewives were discovered in Poultney's Lake St. Catherine in 1997. In 2003, one or two alewives were found in Missisquoi Bay by Quebec researchers, prompting Vermont to start a search of Lake Champlain.
Bernie Pientka, a state fisheries biologist, said researchers running a fish-sampling program in the lake this summer caught three young and one adult alewife in the main lake and the northern section known as the Inland Sea.
The Great Lakes have seen explosions of the alewife population followed by big die-offs that leave piles of fish rotting on beaches.
"This is just the start of their presence here -- you wouldn't expect to see a huge expansion yet," Pientka said. Because every lake is different, it's not certain that alewives will displace smelt as Champlain's dominant small fish, he said hopefully.
The news was particularly discouraging for Mitchell and the Walleye Association because they recently have seen a rebound in walleye populations after years of stocking by the fishing group and the state.
"We've been 20 years in the process figuring out how to get them back into the lake so they can hold their own," Mitchell said.
Now, walleye and other native species will have to accommodate the newcomer. Lake Champlain is so big and complex, there's really nothing humans can do to control the alewives now that they are here, Pientka said.
"We probably will just have to adjust," he said.
The most important thing now, he added, is that anglers take care not to spread the alewives -- which can be mistaken for bait fish -- to other, smaller Vermont water bodies.
"That would be a big concern," he said.