SPOKANE — The Northwest Power and Conservation Council is warning that northern pike have taken hold in Lake Roosevelt.
Northern pike are aggressive predators of other fish and a prohibited species in Washington.
The council says the fish may have been introduced illegally or drifted downriver from infested areas upstream.
An effort to eliminate them using gillnets and a reward fishery is having some success, but officials hope it’s not too little too late.
Lake Roosevelt is the portion of the Columbia River behind Grand Coulee Dam.
Biologists say the number of pike appears to be increasing, as does the size of captured fish.
The Spokane and Colville tribes and the state Department of Fish and Wildlife have been working since 2012 to slow the growth of the pike population.
