Crews to survey St. Clair River for sea lampreys

PORT HURON (AP) - Sea lampreys look alien, and Jim Frazer had a close encounter of the worst kind with one on Saturday during the Port Huron Spring Fling salmon fishing tournament.

"We had one, and I had it stuck to my bicep because my boat mate stuck it to me," Frazer, captain of the Double Down, told the Times Herald of Port Huron.

"It was small, about 5 to 6 inches long."

Sea lampreys, when they're not being attached to anglers, are parasites that attach with a suction cup mouth to fish. They rasp a hole through the scales and skin and feed on blood and other body fluids.

According to the U.S. Fish and Wildlife Service, a sea lamprey will destroy up to 40 pounds of fish during its parasitic adult stage.

Fish and Wildlife will be surveying the St. Clair River from May 20 to June 26 to estimate the sea lamprey population in the river.

Mike Twohey, a supervisory fish biologist at USFWS offices in Marquette and Ludington, was working recently with a crew surveying lamprey populations in the St. Joseph River. He said crews capture larval lampreys that have burrowed into the river's bottom.

"We use a bottom toxicant called bayluscide," Twohey said. "It's a chemical that we use in various forms to kill lampreys. In this formulation, it's a very small amount on a clay pellet that drops to the bottom of the river and does a very slow release.

"That irritates the larvae, and they swim up," he said.

"We have boats on the surface, and when those lampreys reach the surface they collect them. That gives us an indication of how many and how old they are."

Frazer and other anglers said they frequently see lampreys and lamprey marks on fish. He said sometimes the parasites attach to boats.

"A couple of years ago, I picked up the biggest lamprey I've ever seen - 30 inches long," he said. "I think we might have picked it up in the Black River."

Scott Tomlinson, of Sarnia, said it appears there might be more lampreys in area waters than in recent years.

"We caught a fish (Saturday) with a fresh lamprey mark on it," he said. "It was a lake trout."

Twohey said sea lampreys, which invaded the Great Lakes in the 1920s, need a continuing control effort to keep their numbers down.

"We have an ongoing effort to suppress their numbers to reach fisheries targets in each one of the Great Lakes," he said.

"Lake Erie is a particular problem right now because the St. Clair River is increasingly a source of recruitment for sea lampreys," he said. "The reason is the river has become cleaner and more productive for sea lamprey reproduction and growth."

Lampreys that mature in the St. Clair River eventually drift downstream to Lake Erie, Twohey said.

"Lake Erie is the smallest of the Great Lakes," he said. "The target number of lampreys we can tolerate in Lake Erie is about one-tenth of what we can tolerate in Lake Huron."

While people in Europe eat sea lampreys, there's no market for the jawless fish here - nor should there be one, Twohey said.

"The size of the population here is large enough to do damage to fish, but it's not large enough to harvest commercially," he said. "They also contain lots of mercury and should not be eaten."

Sea lampreys prefer fish with small scales such as salmon and lake trout, but "when they enter their parasitic stage, they will latch onto the first meal they can find."

According to a news release from the USFWS, the Great Lakes Fishery Commission started chemical control of sea lampreys in 1958.