Low levels on James credited with keeping invasive silver carp away

• Invasive Silver Carp

This silver carp, caught by North Dakota Game and Fish officials in last October at the base of the Jamestown Dam, weighed 2.4 pounds and was 18 inches long. Officials urge any anglers that come across these fish to bring them to a Game and Fish office. (Photo courtesy / North Dakota Game and Fish)

Talk about it

Last year the region saw two reported cases of a dangerous invasive species. So far this year there have been none and low water is the reason why, according to one expert.

Last October a silver carp was found at the base of the Jamestown Reservoir and another was found in LaMoure, said Gene Van Eckhout, southeast district fisheries manger with North Dakota Game and Fish.

So far low water levels have kept Game and Fish from conducting as many searches as last year. But three searches were conducted: the base of Jamestown Reservoir, the base Pipestem Dam and Dakota Lake National Wildlife Refuge.

“We could use a lot of different equipment types, but the most effective from my understanding and talking to people in South Dakota is the electrofisher,” Van Eckhout said. “You put an electro current in the water and it stuns the fish, and when they come up you can gather fish.”

The problem in South Dakota is much worse at the confluence of the Missouri and James rivers, according to Cari-Ann Hayer, a fisheries science doctoral student at South Dakota State University. Hayer is in the middle of a five-year study of invasive fish and ways to stop them.

“That’s the main thing we’re concerned about is that they’ll over take the river and eat the other fish out of house and home,” Hayer said.

Silver and bighead carp are bottom feeders that eat algae. They disrupt the bottom of the food chain, which eventually affects the top of the food chain. This eventually can kill sport or game fish.

Although not nearly as bad as the Illinois River — where silver carp make up 80 percent of the river’s biomass, which means the mass of all silver carp there is four times the mass of all other life combined — the confluence by Yankton, S.D., is not a pretty sight, Hayer said.

“We’re seeing an exponential increase in numbers every year and they’re just crazy this year down by the confluence area and Mitchell (S.D.) area — they’re everywhere,” she said.

One possible way to stop the spread of silver carp is to find where they spawn and use management techniques, Hayer said.

This summer’s near-drought like conditions have helped this area avoid the hardy pest, she said.

Silver carp typically like flowing water that’s at least nine feet deep. They have been found in lakes but primarily are a river fish.

Hayer believes with the low water this year that the fish has moved downstream back into South Dakota.

Silver carp will also never get north of the Jamestown Reservoir or Pipestem Dam, unless someone transports them.

But not much else can stop the pest, Hayer said.

Her research has indicated the fish can survive in water with low oxygen levels and water that’s 33 degrees cold.

“It’s a classic invasive species. They can survive many different environments,” she said.

A major concern in South Dakota is smaller silver or bighead carp are similar in appearance to shiners or minnows.

In North Dakota, state Game and Fish recently made it illegal to take any bait fish from all of Pipestem Creek below Pipestem Dam or from the James River between the Jamestown Dam and the South Dakota border.

The fish present a danger on rivers where their numbers are great. Easily spooked, they have been known to jump out of the water and hit boaters or watersports enthusiasts.

The problem is so bad in some states that archers hold tournaments where they shoot the fish in the air while riding on a boat.

People in Chicago have even come up with ways to make the bony fish taste better at events like Taste of Chicago, Hayer said.

She hopes the problem doesn’t become that severe in North Dakota.

“We need to do something to kind of help to thwart the population, or keep them in check,” Hayer said.

Sun reporter Ben Rodgers can be reached at 701-952-8455 or by email at brodgers@jamestownsun.com

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