Rainbow Smelt in the Kuskokwim River, Alaska.

The U.S. Army Corps of Engineers prepared an Environmental Impact Statement (EIS) to analyze potential impacts of issuing permits for an open pit, hardrock gold mine near Crooked Creek, Alaska. Transportation infrastructure was one of the primary components of the mine and includes barging along the Kuskokwim River. Increased barge traffic during the spawning and incubation period may affect the Rainbow smelt (Osmerus mordax) population. Given the limited information on rainbow smelt in the project area, the main objectives of this project included assessing spawning run timing, identifying major spawning locations, assessing physical river characteristics along spawning locations, and assessing biological characteristic of smelt segregations, including sex ratio and stage of maturity (pre-or-post spawning). RedFISH provided technical expertise, field support, and survey equipment for Donlin Gold LLC.