Stanley Lake Lake Trout Suppression

The presence of Lake Trout Salvelinus namaycush in Stanley Lake was identified as a potential threat to ESA-listed Sockeye Salmon (Oncorhynchus nerka) recovery efforts in the Sawtooth Valley of central Idaho. The potential for Lake Trout emigration, colonization, and population establishment threatens the currently occupied Sockeye Salmon habitat in Redfish, Alturas, and Pettit lakes, and threatens future recovery efforts. This project aimed to reduce the threat of Lake Trout expansion and colonization into surrounding Sockeye recovery lakes. A 2012 study by IDFG estimated the Lake Trout population in Stanley Lake at 548 individuals (95% CI: 318 – 1,014). The overall goal of this project was 100% removal of the Lake Trout population, but given the difficulty of measuring complete eradication, a target removal of 493 Lake Trout (90% of the 2012 population estimate) was proposed. In four years of netting, IDFG removed 1,057 Lake Trout from Stanley Lake through gillnetting. This reduction of Lake Trout from their 2012 abundance has significantly decreased the risk of Lake Trout emigration and population establishment in the surrounding Sawtooth Valley lakes, thus protecting 1,200 ha of critical spawning and rearing habitat occupied by ESA-listed Sockeye Salmon in Redfish, Alturas, and Pettit lakes.

The removal of fertile Lake Trout from Stanley Lake will significantly reduce the risk of Lake Trout colonization and establishment in Sockeye salmon recovery lakes (Redfish, Alturas, and Pettit). This will protect nearly 1,200 hectares of critical spawning and rearing habitat for Sockeye salmon recovery in the Sawtooth Valley.