Reference | Johnson, K. J. 1990. Regional overview of coded wire tagging of anadromous salmon and steelhead in Northwest America. American Fisheries Society Symposium 7:782-816. |
Abstract | Coded wire microtags (CWTs) were introduced in the Pacific Northwest in the late 1960s as an alternative to fin clipping and external tags for identification of anadromous salmonids in the region, particularly those of hatchery origin. Coastwide use of CWTs quickly followed, and fisheries agencies in Alaska, British Columbia, Washington, Oregon, and California established ocean sampling and recovery programs. Now, over 50 federal, provincial, state, Indian, and private entities release over 40 million salmonids with CWTs yearly. Regional coordination of these tagging programs is provided by the Regional Mark Processing Center operated by the Pacific States Marine Fisheries Commission. The center also maintains a centralized data base for coastwide CWT releases and recoveries, as well as for associated catch and sample data. Data are distributed to users via printed reports, magnetic media, and interactive on-line data retrieval. The system works very well despite its piecemeal growth and dependence on cooperative support by all agencies, but it has several problems. These include improperly designed CWT studies for management purposes, lack of standards for tagging levels, unstable long-term funding, inequitable burdens of cost on recovery agencies, sampling of harvest from many catch areas, un- or misreported harvest biases, lack of standardized statistical procedures for estimating variance, and limitations in marking no hatchery stocks. Progress in solving these problems is reviewed, as are changes introduced by the USA-Canada Salmon Treaty. |
Tag | Coded Wire Tag (CWT) |
Objective | Tagging programs |