BOISE, Idaho (AP) — The Idaho Fish and Game Department is investigating how many illegally-stocked walleye fish are in Lake Cascade after a second walleye catch was reported in four years.
Regional Fisheries Biologist Mike Thomas was fishing while off duty with another angler, Chris Weber, when Weber landed the nearly 3-pound (1.4-kilogram) fish, Boise television station KTVB reported. Another angler reported catching a walleye in the lake in 2018.
“We know that the only way walleye could have gotten into Lake Cascade is through one or more individuals illegally transplanting them there,” Regional Fisheries Manager Jordan Messner said.
State wildlife officials have said walleye are incompatible with the perch in Lake Cascade and its fisheries downstream, such as the Brownlee, Oxbow and Hells Canyon reservoirs. Walleye commonly prey on other fish.
It is illegal to release live fish or their eggs in Idaho without the permission of the Fish and Game Department director. It is also illegal to possess or transport the live fish or their eggs without permission.
"Two reports over a four-year span means Walleye could very well be established in the lake, but the fact that we haven’t encountered them during extensive fish population surveys or angler surveys means they are likely not very abundant yet,” Thomas said. “Our fisheries program will be shifting gears over the coming weeks to try to determine the extent of their occurrence in the lake, and we’ll develop a game-plan for moving forward.”
Regional Fisheries Manager Joe Kozfkay said Lake Cascade lacks forage fish like smelt, shad or minnows, so an established walleye population in the lake could create a threat to the perch population. The lake is a popular destination for perch fishing.
Citizens Against Poaching is offering a reward for information about the case.