Saturday, October 8, 2016

Feds to treat Grand River for invasive sea lamprey

In its on-going running battle with the destructive and invasive sea lamprey, the U.S. Fish and Wildlife Service intends to treat the Grand River with a lampricide.

Treatment is expected to run through the latter half of October and will follow the permitting requirements of Ohio, federal officials say.

The Grand River is a prime spawning ground for sea lampreys which can migrate at least as far upstream as the Harpersfield dam in Ashtabula County. It is here where federal funds will be used to help restore the dam which has largely blocked further upstream migration but whose structure is fast crumbing.

“Application will be complete in about four day,” said federal agency spokesman, Scott Grunder.  “Application dates are tentative and may be changed based upon local weather or stream conditions near the time of treatment.”

Grunder noted the seedy side of the sea lamprey, where adults spawn in favorable stream, the larvae eventually transforming into parasitic adults.

After maturing, adult sea lampreys – individuals can grow to about 25 inches in length - then migrate into the Great Lakes. There they kill fish by utilizing their circular rows of teeth to rasp holes into the sides of a host fishes. The lampreys then consume the fishes’ fluids such as blood. It can take weeks or longer for the host to die, and its been estimated that one sea lamprey can kill up to 40 pounds worth of host fish in a lifetime.

Sea lampreys are not native to Ohio nor Lake Erie, having arrived via the Welland Canal  with the first Ohio sighting being reported in 1927. It is generally accepted that this scourge was the major reason for the collapse of the Great Lakes’ lake trout fisheries.

State and federal fish and wildlife agencies have been at war with this invasive pest ever since.

“Failure to kill the larvae in streams would result in significant damage to the Great Lakes fishery,” Grunder said. “ Infested tributaries must be treated every three to five years with lampricides to control sea lamprey populations.”

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 stream 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 are certified by (state/provincial) regulatory agencies for aquatic applications of pesticides.

One reason for the concern is that Ohio has six native lamprey species, none of which pose a risk to fishes. And the lampricide used can – and does – kill other aquatic species such as mud puppies.

Grunder said the government’s sea lamprey control program is contracted through the Great Lakes Fishery Commission to the U.S. Fish and Wildlife Service and Department of Fisheries and Oceans Canada. 

The Commission initiated chemical control of sea lampreys in 1958.  Since that time the highly successful program has contributed significantly to the maintenance of the $7 billion Great Lakes sport and commercial fisheries.

“The Commission is committed to delivering a sea lamprey control program that practices good environmental stewardship,” Grunder said.

 To support the continued safe use of lampricides the Commission recently conducted a series of studies at a total cost of $6 million to assess the effects of the lampricides on human health and the environment.  In addition to these studies the Commission also has implemented a research program to develop alternative control techniques.  Among efforts, say Grunder, the Commission also is developing a strategy to increase the number of barriers on lamprey-producing streams.

“And we are conducting research into barrier design, traps, attractants, and biological controls, too,” Grunder said..

In terms of human health, both the U. S. Environmental Protection Agency and Health Canada Pest Management Regulatory Agency have reviewed human health and environmental safety data for lampricides. In 2003 these partners concluded that the lampricides “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,” Grunder said. “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.”

- Jeffrey L. Frischkorn

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