ALPENA TOWNSHIP - A United States Fish and Wildlife Service crew will be coming to Long Lake Creek next week to look for sea lamprey larvae.
Crews will use pellets of a special chemical to drive the larvae to the surface of the water, where they can be collected, measured and counted, Ludington Biological Station Supervisor Jeff Slade said. Along with the creek itself, crews will check Devils Lake, through which the creek flows. The chemical will be used in deeper waters, while crew members will use backpack electrofishers for shallower parts.
By conducting the survey on a regular basis, USFWS crews know when and where to treat to rid streams of these invasive, parasitic creatures, Slade said.
"Once we have an estimate of how many larvae, and how large they are... we know where to apply lampricides," he said.
Crews will be working over the course of five days starting Monday, and returning later in the month to treat the creek, Slade said. Long Lake Creek is one of many in the area the USFWS treats for lampreys. Devils River in Ossineke is another, as is Swan River near Rogers City.
While growth rates can vary, lampreys typically spend four to six years in the larval stage, Slade said. During that time, they're buried in the sand or silt in river beds. Later in life they undergo a physical change, developing their teeth and eyes. They undergo another change as well.
"Their digestive tract changes to where they now need to feed on the blood and body fluids of fish," he said.
This is why lampreys are a problem. In the 12 to 18 months they spend feeding, they can destroy up to 40 pounds of fish, Slade said. They prey on whitefish and lake trout, as well as other big predators. Treating Long Lake Creek is just a tiny part of a massive effort to eradicate the parasites from the Great Lakes.
Even though Long Lake Creek is small, compared to the Au Sable River or the Cheboygan River, it's still an ideal place for lampreys to breed, Slade said.
"They still can produce tens if not hundreds of thousands of larval sea lamprey," he said. "If we didn't monitor these streams and treat them, we would have a lot more sea lampreys in Lake Huron."