Alaska wipes out invasive pike with rotenone, restocks lake with 6,836 Arctic char

Alaska biologists used rotenone, a naturally occurring piscicide, to purge an invasive northern pike population from a secluded lake in Southcentral Alaska. The chemical was applied to the lake and its outlet streams in fall 2012, and subsequent netting and electrofishing confirmed that no pike survived. After the toxin degraded by early 2013, the Alaska Department of Fish and Game relocated held native fish and, on June 17, 2013, released 6,836 hatchery-reared Arctic char fingerlings, derived from Stormy Lake and Dolly Varden Lake lineages, to rebuild the native fish community.

Monitoring shows the char are surviving and growing, indicating a return toward pre-pike conditions. The agency has repeated this eradication-and-restocking model at other isolated lakes such as Sand, Anderson and Kings, while using suppression tactics in larger, connected systems. Public outreach and environmental assessments accompany the treatments to address community concerns about the temporary loss of all fish in the waterbody.