Sea lamprey treatment planned for Little Manistee River

Sea lamprey are parasites that latch onto fish, and eventually kill their host. (Public domain)

Sea lamprey are parasites that latch onto fish, and eventually kill their host. (Public domain)

MANISTEE — U.S. Fish and Wildlife Service personnel will apply lampricides to the Little Manistee River system in Lake and Manistee counties this month to kill sea lamprey larvae burrowed in the stream bottom.

The applications will be conducted between July 15 and 24 in accordance with State of Michigan permits, but will only take about six days. Application dates are tentative and may be changed based upon local weather or stream conditions near the time of treatment.

Sea lamprey larvae live in certain Great Lakes tributaries and become 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 fishery. Infested tributaries are treated every three to five years with lampricides to control sea lamprey populations.

“This is something we’re familiar with our area,” said Scott Heintzelman, a technician supervisor with the Michigan Department of Natural Resources Fisheries Division. “We have really high water quality here so they like to spawn in our rivers and streams.”

Heintzelman does a lot of work at the Little Manistee River Weir.

He said the river generally gets a sea lamprey treatment about every three years.

Lampricides are selectively toxic to sea lampreys, but a few fish, insect, and broad-leaf plants are sensitive. Persons confining bait fish or other organisms in stream water are advised to use an alternate water source because lampricides may cause mortality among aquatic organisms stressed by crowding and handling. Agricultural irrigation must be suspended for 24 hours, during and following treatment.

“Sometimes there are minor fish kills associated with it,” Heintzelman said. “It’s a necessary evil to protect the greater good of the fishery. There’s a little bit of collateral damage, but they’ve done a really good job, and there haven’t been a lot of problems in our area.”

The U. S. Environmental Protection Agency and Health Canada Pest Management Regulatory Agency have reviewed human health and environmental safety data for lampricides, and in 2003 concluded that 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.

However, as with any pesticide, the public is advised to use discretion and minimize unnecessary exposure.

Extensive preparations are required for a safe and effective stream treatment. Prior to treatment, personnel collect data on stream water chemistry and discharge. In addition, they may conduct on-site toxicity tests with lampricides and stream flow studies with dyes that cause water to appear red or green.

Lampricides are carefully metered into the stream for approximately 12 hours, and continually analyzed at predetermined sites to assure that proper concentrations are maintained as the lampricides are carried downstream. Applicators are trained and certified by state regulatory agencies for aquatic applications of pesticides.

For additional information, call 1-800-472-9212. TTY users may reach the Marquette or Ludington Biological Stations through the Michigan State Relay Service at 1-800-649-3777.

For more information on the U.S. Fish and Wildlife Service, visit www.fws/gov.

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Posted by Justine McGuire