Tag Lab
Coded Wire Tag Laboratory - fact sheet last updated August 2010

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 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, 78 agencies in 5 states and British Columbia have used 45,691 codes and 817 miles of wire to tag 1.3 billion salmon and steelhead.

Alaskan Releases

Since 1973, 21 agencies representing 62 different hatchery sites have used 8,087 unique codes and 58 miles of wire to tag 111 million salmon and steelhead released at 328 locations in Alaska.

Alaskan Sampling Information

Since 1976, 128 million salmon were sampled in commercial, cost recovery, and sport fisheries and spawning grounds at 216 locations throughout Alaska. To date, 310,513 individual sampling events have been recorded on forms and entered into the database. 1.17 million heads weighing approximately 906.7 tons were removed from adipose clipped salmon and sent to the lab in Juneau for tag removal and decoding.

Database and Report Generation Statistics

Thirty five years of Alaskan catch statistics, sampling information and CWT tag recoveries, and 43 years of coast-wide release data are maintained in a dedicated database. Catch/sample statistics for 574 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. When sampling commercial deliveries of salmon our personnel now enter all information into a hand held computer. 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

Related Web Sites

Northwest Marine Technology is the provider of most tags and specialized equipment used for tagging Pacific salmonids.   The Regional Mark Processing Center maintains the authoritative U.S. copy of the complete coastwide Coded Wire Tag database. They also coordinate salmon fin marking.   The North Pacific Anadromous Fish Commission is primarily concerned with high seas salmon issues. It includes Japan, Russia, the U.S., and Canada. An extensive library of reports are available.    Columbia River Inter-Tribal Fish Commission maintains technical papers of Washington and Oregon salmon based on CWT analysis.   The Pacific Salmon Commission relies extensively on CWT studies to oversee treaty compliance.

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Coded Wire Tag Laboratory Forms in PDF format:

Form	Last Modified	Size
Cook Inlet, Westward and Aleutian Regions Commercial Fisheries Sampling Form	03/24/2011	141 KB
Cook Inlet, Westward and Aleutian Regions Rack & Escapement Sampling Form	03/24/2011	118 KB
Non Southeast Regions Sport Fisheries Sampling Form	03/24/2011	167 KB
Southeast Region Commercial Fisheries Sampling Form	03/24/2011	137 KB
Southeast Region Rack & Escapement Sampling Form	03/24/2011	124 KB
Southeast Region Sport Fishery Sampling Form	03/24/2011	183 KB
Coded Wire Tag Shipment Summary Form	03/24/2011	88 KB
Coded Wire Tag Release Information Form	03/05/2008	151 KB
Non Coded Wire Tag Release Information Form	03/03/2008	144 KB
Coded Wire Verification Form	02/12/2007	41 KB

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