Coded-Wire Tagging Coho Smolt

After tagging, the fish pass a sensor to check for the tag and then continue down the hose to the recovery & holding pen. When a batch of same size fish are completed the fish are released.

Sandee uses a notched dowel to explain the binary bar code found on each tag.

Two sizes of wire tags can be used. This project uses the 1mm length tag. Smaller fish would require using the 0.5mm size.

ADDENDUM: Since this article was written more improvements have been made in the coding process. The manufacturer, Northwest Marine Tech., of the wire tags has recently moved away from binary wire to decimal wire (0, 1, 2, 3, etc.) because it can be read faster and it doesn't require several hours of training to insure that tag readers are accurate. Now anyone can pick up a tag and read the numbers. Tags come in two formats, batch (all the tags on a spool are given the same code) and sequential (individual fish can be given a unique identifying code).