Fish kill minimal after lamprey treatment

A sea lamprey in a trout. A U.S. Fish and Wildlife effort to kill sea lamprey larva also killed about 200 fish, mainly salmon, when the operation was done on the Manistee River earlier this week. (Courtesy Photo)

A sea lamprey in a trout. A U.S. Fish and Wildlife effort to kill sea lamprey larva also killed about 200 fish, mainly salmon, when the operation was done on the Manistee River earlier this week. (Courtesy Photo)

MANISTEE COUNTY — About 200 salmon were killed after sea lamprey control efforts in the Manistee River, despite complaints online to the contrary.

On Aug. 29 and 30, the Ludington biological station of the U.S. Fish and Wildlife Service put two chemicals, TFM and Bayer, into the river to help kill sea lamprey larva before they become fully grown.

“In just an informal count, while some of my staff were moving down river the day of between the Tippy Dam and High Bridge public access sites, we saw 175 chinook salmon that had died,” said Scott Grunder, supervisor at the Ludington biological station for the U.S. Fish and Wildlife Services office. “Then we documented afterward when we were doing our formal survey, we had another 30 chinook salmon.”

Rumors spread through social media and word of mouth that more fish were killed than reported because of the treatment.

“There certainly was not thousands of dead salmon,” Grunder said.

Staff from the office put two chemicals, TFM and Bayer, in the water — giving it a yellow tint — to help kill sea lamprey larva before they become fully grown. This process is done every three years.

The invasive animal, native to the  uses its suction mouth to attach to a fish and use their saliva to keep its blood from clotting and feed on its blood and bodily fluids, eventually killing them.

“We treat two tributaries of the Manistee River — the Bear Creek and Pine Creek (tributaries) in Manistee County,” Grunder said.

Tippy Dam was used as an application point to put the chemicals in the river, he said.

“We have staff monitoring the chemical bank the entire time, from release and all the way to 24 hours later when it reaches Manistee Lake,” Grunder said. “A chemical treatment takes 12 hours and generally the chemical bank leaves the system after 24 hours.”

Another species sensitive to the chemicals is the juvenile lake sturgeon, however the U.S. Fish and Wildlife Service worked with the Michigan Department of Natural Resources and the Little River Band of Ottawa Indians to net the fish a week before the treatment.

The sturgeon were later stored in tanks until the treatment was done, at which time, they were put back in the water.

“The Manistee River is third largest producer of sea lamprey larvae in Lake Michigan,” Grunder said. “It could produce millions of larva if untreated.”

Chelsea Pete, manager of D Loop Outfitters in Wellston, said many people are worried about the fish being killed.

“(The fish) are dying because when you’re putting the chemical into the water, they can’t recoup from it because of the warm water temperatures,” Pete said. “The warm water makes them weak. They need the cold water.”

The weakened fish then can’t lay eggs, for example, and die off, she said.

“They’ll feed off that fish until there’s nothing left,” Pete said.

Grunder said after a poor treatment in 2012, a retreatment was done in 2013 then again this year.

“This time around, I told my staff I wanted them to be aggressive and go after them,” he said. “We were not out of bounds as far as our chemical concentrations go. Anglers and state agencies expect us to be effective.”

Sea lamprey-infested tributaries have been treated since the 1950s.

“Back in the 1950s, before sea lamprey control, you had literally somewhere between 2 and 4 million adult sea lamprey in Great Lakes basin,” Grunder said. “Since that time in the 60 years, we started treating it, we’ve reduced those numbers by 90 percent.”

He said the reason anglers enjoy the salmon and lake trout fisheries is because of excellent fishery management by state agencies and sea lamprey control.

“We don’t like seeing these kind of mortality events,” Grunder said. “They rarely occur, but they do occur. They are an incredibly voracious and adaptable animal. If you don’t be aggressive with them, they come back with a vengeance.”

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Posted by Sean Bradley

Sean is the city and cops and courts reporter for the News Advocate, he also is in charge of the entertainment and Reasons to Celebrate pages. He can be reached at (231) 398-3109 or sbradley@pioneergroup.com.

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