Efforts underway to control parasitic sea lampreys

Jul 31, 2015

Lake Erie is a popular fishing destination for many Western New York anglers in the summer. But one type of fish can ruin all the fun – sea lampreys. That's why a U.S. Fish and Wildlife Service crew will conduct a survey on an area of Cattaraugus Creek in mid-August to help control the invasive species.

The parasites attach to fish with a suction cup-like mouth, pierce a hole through the fish’s scales and skin, and then feed on blood and bodily fluids. On average, a single lamprey can destroy up to 40 pounds of fish during its feeding period.

Sea lampreys feed on other fish, using a suction disk mouth filled with small sharp teeth to attach to a fish, puncture its skin and drain its body fluids.
Credit dec.ny.gov

“We want to go out and find where they area, quantify their abundance and determine their distribution in the stream,” U.S. Fish and Wildlife assessment team leader Aaron Jubar said. “That information is used for any control actions.”

Sea lampreys came to the Great Lakes during the 1920s and have been destroying fishing populations ever since. Lampreys’ destruction on fish peaked in the 1960s, but things have since vastly improved.

“We’re to the point where we’re at about 10 percent or less of the number of lampreys that are in the Great Lakes than they use to be historically,” Jubar said. “Yes, there’s still a problem, but we’ve really minimized their impact on the fisheries.”

Tributaries, like the Cattaraugus Creak, have lamprey larvae living there. Adult lampreys lay eggs in gravel nests and the larvae burrow in the bottom of streams for several years. It’s not until they become strong, parasitic adults that they begin to injury and kill fish.

“When they’re in the stream, in the larval stage, they’re actually completely harmless,” Jubar said. “They are burrowed into the stream bottom, so you typically never even see them. They filter feed on organic material and other small micro organisms.

“So they really don’t have any impact, if any, when they’re in that stage. It’s when they turn into the parasite and move out that they cause all the damage.”

One action Jubar and his staff will do once the survey is done is to spread a chemical known as lampricide. Lampricide forces the larval lampreys to the surface of the water where they can then be removed from the creek. Lampricide is spread in Cattaraugus Creek every two or three years and was last spread in the spring of 2013.

After a historically cold and snowy winter, Jubar said that lampreys started the spring very weak. But once July and August comes around, lampreys are in prime condition.  

Lampreys prey on Lake Erie's lake trout, brown trout, sturgeon, whitefish, walleye, catfish and steelhead, among others.

“They do gravitate toward those cold water species as host fish,” Jubar said. “We’ve definitely seen and heard from some of the fishery managers that they’re very concerned because they can have devastating impact on things like steelhead and that’s a huge fishery out there, especially in the spring.”

The crew will conduct the survey August 11-20.