Tag Lab
About Us

The Coded Wire Tag Lab is the centralized state resource for tracking salmon using microscopic coded wire tags (CWT). We maintain a detailed database that is used to estimate survival and run timing of tagged salmon releases harvested in compliance with Pacific Salmon Treaty strictures and various other biological parameters. The cooperative coast wide coded wire tag program is composed of member agencies in California, Oregon, Washington, Idaho, British Columbia and Alaska, all of which serve as participating members of the Pacific Salmon Commission.

What is a Coded Wire Tag?

Coded Wire Tags (CWT) are small pieces (0.25 x 0.5 or 1.0 mm) of stainless steel wire that are injected into the snouts of juvenile salmon and steelhead. Each tag is etched with a decimal or binary code that identifies its release group. Until recently all tagged fish also had their adipose fin removed. The adipose clip is the external flag identifying which adult fish bear a CWT to samplers, processors and fishers. Heads of all adipose clipped fish recovered in Alaskan waters are sent to a lab in Juneau where the tags are found using very sensitive metal detectors, dissected out of the head and decoded. Release, catch/sample and recovery data are merged and estimates of contribution of tag groups to sampled fisheries are updated each day. This stock identification tool is used by researchers and managers to evaluate success of hatchery practices, estimate survival, find out where release groups are caught and to determine stock contribution of sampled fisheries. Alaska's CWT release and recovery program is an integral part of a large coordinated coastwide program.

Coastwide Releases

Since 1968, 84 agencies in 5 states and British Columbia have used 57,302 codes and 1,348 miles of wire to tag 1.90 billion salmon and steelhead.

Alaskan Releases

Since 1973, 23 agencies representing 51 different hatchery sites have used 9,776 unique codes and 80 miles of wire to tag 136 million salmon and steelhead released at 347 locations in Alaska.

Alaskan Sampling Information

Since 1976, 137 million salmon were sampled in commercial, cost recovery, and sport fisheries and spawning grounds at 223 locations throughout Alaska. To date, 429,248 individual sampling events have been recorded on forms and entered into the database. 2 million heads weighing approximately 1,191 tons were removed from adipose clipped salmon and sent to the lab in Juneau for tag removal and decoding.

Database and Report Generation Statistics

Forty-Six years of Alaskan catch statistics, sampling information and CWT tag recoveries, and 54 years of coast-wide release data are maintained in a dedicated database. Catch/sample statistics for 616 strata and fishery contribution estimates are updated daily. Access to CWT information is provided over the World Wide Web through a report generator which allows users to filter data on a wide variety of variables. Results of queries can be provided to requestors as web screens, email attachments, or FTP files. They are suitable for further manipulating using tools like Excel and Access. Also, customized reports can be run by lab staff upon request. Contact us if you need assistance with customized data retrieval.

Field Sampling with hand held computers

In 2006, the Division of Commercial Fisheries of the Alaska Department of Fish and Game instituted an Electronic Sampling application named CWT Mobile for the purposes of reducing paper form data capture of Commercial Samples. Most commercial and sport deliveries of salmon are now entered into a handheld computer instead of paper forms. The data are transmitted over the internet to servers at the MTA Lab, validated and moved into the centralized database nightly. This approach speeds up sampling, reduces errors, and provides managers with very accurate and current data. For more information here is a Power Point presentation of the Electronic Sampling application and process:
Electronic Sample Acquisition in Alaska (PPT 1,963KB)