Sea Lamprey Traps at $1.7 Million Will Protect Lake Huron from Invasive Species, Officials Say

Officials claim that robust invasive species of sea lamprey will be kept out of Lake Huron by permanent traps costing $1.7 million.

On the East Branch of the Au Gres River, which is a part of the Lake Huron watershed, federal authorities have finished setting a new trap to catch invasive sea lamprey.

Sea Lamprey Traps

The Iosco County river has a $1.67 million permanent sea lamprey trap installed, according to the US Army Corps of Engineers and Great Lakes Fishery Commission. Sea lampreys, reaching counts of 4,500, enter Lake Huron each year. Each invasive species has the potential to exterminate up to 40 pounds of other fish each year, including lake trout and Pacific salmon.

Twelve miles of the Au Gres River's East Branch have been designated as blue-ribbon trout streams. The river, which was rerouted to Lake Huron through the Whitney Drain in the 1920s, is still well-known for its annual salmon and steelhead runs.

Permanent Traps vs. Portable Traps

The invasive fish, which resemble eels, latch on to other fish species using their large, round mouths and feed on their hosts' bodily fluids using their sharp, curved teeth and rasping tongues, according to officials. Previous efforts involved using portable traps in this river have been unable to catch many of these fish.

Steve Check, the project manager for the Corps, said that it was planned for the new permanent trap to be built with higher water flows at the entrance to draw sea lampreys, which they anticipate will lead to significantly higher catch rates.

He explained that because of its low cost and adaptable design, this new trap will essentially serve as a template for projects to build similar traps in the future.

According to Jim McKane, the commission chairperson, this kind of trap is one of many that are used to control the sea lamprey population, and this river is one of the nearly 60 tributaries that have been caught.

The project was supported by a partnership between both the Corps and the commission to restore the Great Lakes fishery as well as its ecosystem. The Great Lakes Restoration Initiative provided additional funding, and the Michigan Department of Natural Resources supplied the land for the trap.

The contractor from Muskegon started the project in November and finished it by the end of January. The US Fish and Wildlife Service will be in charge of maintaining the structure, MLive reports.

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Sea Lampreys

The parasitic fish known as sea lampreys (Petromyzon marinus) are natives of the Atlantic Ocean, according to the Great Lakes Fishery Commission. Sea lampreys have endured at least four major extinction events and have remained virtually unchanged for over 340 million years. They parasitize other fish by consuming their blood and other bodily fluids.

Sea lampreys are distinct from many other fishes as they lack jaws and other bony structures in favor of a cartilage-based skeleton. Although sea lampreys look a lot like eels, they are unrelated to them and can be distinguished by their distinctive mouth, which consists of a sizable oral sucking disk surrounded by sharp, horn-shaped teeth and a razor-sharp rasping tongue.

Sea lampreys use their suction cup mouths to cling to fish before digging their teeth into the flesh to gain traction. Once firmly grasped, sea lampreys use their pointed tongue to rip through the fish's skin and scales. Sea lampreys feed on the fish's bodily fluids in a manner akin to a leech. It secretes an enzyme, preventing blood from clotting.

According to the NOAA National Ocean Service, the Welland Canal, which connects Lake Ontario and Lake Erie, was built in 1829 to promote prosperity and economic growth in the upper Midwest of the newly formed United States of America. They had no idea that by allowing the sea lamprey, a voracious Atlantic predator, to pass through, it would eviscerate other commercially and economically valuable species and obliterate the Great Lakes' 10-million-pound-per-year trout fishery.