A Device to Detect Magnetized Wire Tags in Migrating Adult Coho Salmon

A device that can be used for rapid detection and separation of migrating adult coho salmon marked as juveniles with magnetized wire tags was tested in November and December 1967 at the Minter Creek Hatchery of the Washington Department of Fisheries. About two-thirds of the test fish in the holding pond entered the structure; the device correctly separated 89% of the fish with tags and 99% of the untagged fish. Placement of this equipment in streams, fish ladders at dams, and in hatcheries, would facilitate removal of tagged specimens from the general population of fish.