Idaho Department of Fish and Game biologists will be joined by staff and volunteers from Friends of the Teton River next week as they conduct an “electrofishing” study on the Teton River. The study is part of a bi-annual survey to assess the river’s valuable fishery. “Electrofishing” involves passing a mild electrical current through the water in order to efficiently capture fish for survey purposes. The electrical current causes involuntary muscle spasms in fish, resulting in their movement toward the source of the current. The fish are then netted, and placed into a holding tank with fresh water and a mild anesthetic. Once captured, fish are examined, weighed and measured. Many of the fish captured this year will also be implanted with Passive Integrated Transponder tags, which allow researchers to track their movements over time. The fish are then returned to the water, unharmed.