Nevada game wardens who spend most their time hunting down big-game poachers are focusing on a serious threat to nature in a lake: An invasive fish species that eats all the other fish prized by anglers and then turns cannibalistic.

The Nevada Department of Wildlife is offering a $10,000 reward to help nab the culprit who apparently dumped Northern pike in Comins Lake, a popular fishing spot surrounded by mountains near Great Basin National Park.

By all accounts, Comins Lake was well on its way to recovery after the state restocked the fishery with largemouth bass, brown and rainbow trout in 2015.

But the invading Northern Pike were discovered again last month by a fisherman who caught one and called state wildlife officials. Five more have been confirmed since then.

Northern pike may not sound as scary as piranhas or the Asian swamp eel — two of the other half-dozen fish that Nevada law singles out as invasive, injurious aquatic species.

But with its long, needle-sharp teeth, the voracious predator that sometimes grows longer than 4 feet (1.2 meters) can wipe out an entire fishery.