Electrical Anesthesia for Immobilizing Adult Coho Salmon in Freshwater

Abstract

Wild adult coho salmon Oncorhynchus kisutch, returning to spawn, were sampled in freshwater with a DC shocking basket. Electrical anesthesia briefly immobilized fish and expedited sampling without the adverse effects of tricaine methanesulfonate (MS-222) or the excessive handling associated with physical restraint. Coho salmon mortality attributed to the shocking basket was 0.2% at Yehring Creek and 4.2% at the Chilkoot Lake weir. This is the first reported freshwater application of electrical anesthesia for handling salmonids.