An angler's unexpected catch in Island Park Reservoir sparks concern over ecological impact. On January 3, 2026, an angler ice fishing for trout made a surprising discovery: a 5-inch-long Yellow Perch, an invasive species not native to the reservoir. The angler promptly reported the catch to the Citizens Against Poaching hotline, leading to a swift response from the Idaho Department of Fish and Game. Conservation Officers confirmed the catch and identified it as an illegally stocked Yellow Perch, marking the first-ever confirmed sighting in Island Park Reservoir. This discovery raises serious ecological concerns, as the reservoir is managed as a hatchery-supported Rainbow Trout fishery. The illegal introduction of live fish in Idaho without proper permits is a violation of state law and can have severe ecological consequences. The financial burden of restoration efforts, which could reach hundreds of thousands of dollars, and the potential for felony charges, highlight the gravity of the situation. Fisheries Manager Brett High emphasizes the importance of monitoring fish populations and the potential impact of the Yellow Perch on the trout population, which is Idaho's most popular species. The perch, a popular sportfish, competes with trout for the same food source, often leading to poor survival and growth. The illegal introduction of this species could disrupt ongoing collaborative efforts to improve water quality and the overall health of the reservoir's fishery. Fish and Game is urging anglers to harvest all Yellow Perch they encounter in the reservoir, with no bag limits or size restrictions. The Citizens Against Poaching hotline encourages citizens to report any wildlife violations, including the transportation of live fish, to help protect Idaho's natural resources. The public's vigilance and cooperation are crucial in preventing further ecological damage and ensuring the preservation of Island Park Reservoir's ecosystem.