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Frankenfish expand 'phenomenally more than we expected'

Friday - 5/6/2011, 7:28am  ET

The snakeheads have expanded to the Chesapeake Bay and tributaries other than the Potomac River. (WTOP Photo/Andrew Mollenbeck)
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Andrew Mollenbeck,

OCCOQUAN, Va. - Northern snakehead fish are expanding beyond the Potomac River, and even with incentives to kill them, wildlife experts are unsure what impact the fish will have on the ecosystem.

"There's absolutely no question the range of the snakeheads increased phenomenally more than we expected," says John Odenkirk, a district fisheries biologist with the Virginia Department of Game and Inland Fisheries.

The snakeheads have expanded to the Chesapeake Bay and even into other tributaries that feed the bay.

"Nobody knows for sure what the impacts - the true impacts - are going to be, and that's going to kind of depend where the population tops out," Odenkirk says.

What is known is that the fish, native to Asia, are predators that could endanger native species.

The impacts to the ecosystem and other important recreational and commercially-valued fisheries "could be significant," according to a statement released by the Maryland Department of Natural Resources.

"We've seen the numbers increase, we've seen the range increase, but it's hard to point your finger at what the actual impact has been," Odenkirk adds.

It is illegal to possess live snakeheads. In Maryland, there is an incentive for anglers to kill them.

The DNR, the Potomac River Fisheries Commission and the U.S. Fish and Wildlife Service are awarding prizes for those who catch, kill and submit photos of snakeheads.

Until Dec. 31, anyone who catches a northern snakehead and posts the photo of the catch on DNR's Angler's Log can win a $200 rod-and-tackle package, a Maryland State Park Passport and a 2012 Potomac River fishing license. For details of how to partipate, click here.

"We do not want snakeheads in our waters," says DNR Inland Fisheries Director Don Cosden, in a release.

"This initiative is a way to remind anglers that it is important to catch and kill this destructive species of fish."

The incentives also attempt to counter the unexpected population explosion, particularly in places previously considered intolerable for the snakeheads.

"We expected that Great Falls would the northern barrier and the salinity - the more saline waters - of the lower Potomac system to be the southern barrier," says Odenkirk.

But in reality, the fish can tolerate some salinity, especially juvenile snakeheads.

"What happens is with fresh water, when it rains, it's less dense than the heavier salt water, and the fish are expanding their range by riding these [waters] down river, and then as the waters recede and it starts to get salty, they go up into the tributaries," Odenkirk says.

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