Lampricides will be applied to sections of McKay, Prentiss, Hessel, and Caribou creeks in Mackinac and Chippewa counties to kill sea lamprey larvae burrowed in the stream bottom between April 30 and May 7. The actual dates of application will be determined upon local weather and stream conditions near the time of treatment. Applications on each stream will be complete in 24 to 36 hours.

Sea lamprey larvae live in certain Great Lakes tributaries and transform to parasitic adults that migrate to the Great Lakes and kill fish. Failure to kill the larvae in streams would result in significant damage to the Great Lakes fishery, the U.S. Fish and Wildlife Service reports. Infested tributaries must be treated every three to five years with lampricides to control sea lamprey populations.

Treatment of McKay, Prentiss, Hessel, and Caribou creeks will destroy an estimated 77,300 larval sea lampreys, including about 3,500 that would be expected to transform and migrate to Lake Huron to begin their parasitic life cycle. Each lamprey in Lake Huron consumes nearly 40 pounds of lake trout and salmon during its parasitic life.

The lampricides (Lampricid and Bayluscide) pose no unreasonable risk to the general population and the environment when applied at concentrations necessary to control larval sea lampreys, according to the U. S. Environmental Protection Agency. As with any pesticide, the public is advised to use discretion and minimize unnecessary exposure. Persons confining bait fish or other organisms in stream water are advised to use an alternate water source. Agricultural irrigation must be suspended for 24 hours during and following treatment.

Before treatment, workers collect data on stream water chemistry and discharge. They may conduct on-site toxicity tests with lampricides and stream flow studies with dyes that cause stream water to appear red or green.

Applicators are trained and are certified by Michigan regulatory agencies.