KANARRAVILLE, Iron County — The Utah Division of Wildlife Resources said Friday it has discovered three illegally stocked fish species in Kolob Reservoir.

According to the division, the species — yellow perch, green sunfish and bluegill — pose a substantial threat to the endangered fish species that live downstream in the Virgin River. As a result, the reservoir will be drained this fall and treated with rotenone to remove all the fish.

Meanwhile, the daily trout limit has been bumped from two to eight in order to get as many fish out of the reservoir before it is drained. In addition, there are no size restrictions on the fish that are caught.

Richard Hepworth, the division’s southern region aquatics manager, said crews hope to drain the reservoir in October, and if everything goes well, it will be restocked by November, allowing the trout time to grow for next season.

A $3,000 reward is being offered for details that lead to the prosecution of those responsible for introducing the three species to the reservoir. Anyone with information can call Utah's Turn in a Poacher (UTiP) hotline at 1-800-662-3337.