Coded Wire Tags (CWT)
Coded Wire Tags poster
Coded Wire Tag in fish
Clipped Adipose Fin
You can help in the monitoring of Great Lakes salmon and trout populations. Many of these fish have been marked with a small coded-wire tag, which is implanted in the head of the fish, but invisible to the naked eye.
If you catch a fish that is missing only the adipose fin (see photo, above), it is possible that it has had a coded-wire tag implanted into its snout. Please record the following information: date caught, location caught, species, length, weight, sex (if possible) and fin clip. The data obtained can be recorded on the coded wire tag recovery form.
Remove and freeze the fish's snout (part of head from behind the eyes forward), and drop off the snout along with data sheet at a drop of location, or call 517-284-5830 for a list of local sites. Please do not mail! If a tag is extracted, the fishermen will be notified of the age and stocking location of their catch.
CWT recovery form »
Drop off locations »
Additional Information about CWT:
- All samples for CWT processing end up at the Charlevoix Fisheries Research Station
Once the samples reach the Charlevoix Fisheries Research Station, tags are extracted, read under a microscope and both the angler and fish data is entered into a large database. A letter is then generated telling the cooperating angler the species, age and stocking location of the fish.
- Statewide Coded Wire Tagging and Recovery Program
This program is designed to fin clip and mark experimental lots of fish and then to compile all data from CWT studies into one database. Fish tagged to date include Atlantic salmon, brown trout, chinook salmon, coho salmon, lake trout, rainbow trout, and lake sturgeon.
- Influence of Total Length and Condition at Stocking on Chinook Salmon Survival and Time at Large
Study objectives include tagging chinook salmon to determine the influence of length and condition on post-stocking survival, return by age and size, and cost per return.
- Evaluation of Returns of Salmonids to Weirs in Michigan's Waters of the Great Lakes
The study objectives are to monitor annual weir harvest and operations, and provide annual size-at-age and weir return summaries for fisheries managers and interested public.
- Coded-Wire Tag Returns in the Sport Catch - Port Specific Results
Results are from CWT's that were collected from the sport catch at various ports. The total number of CWT's returned by port for multiple species (example; chinook salmon, lake trout and steelhead) over the last 5 years is reported. Additional summaries (by age, by stocking site) are included for most ports.
Stocking Information from the Great Lakes Fish Stocking Database
Adlerstein et al. 2007. Lake Trout Movements in US Waters of Lake Huron Interpreted from Coded Wire Tag Recoveries in Recreational Fisheries
Adlerstein et al. 2007. Estimating Seasonal Movements of Chinook Salmon in Lake Huron from Efficiency Analysis of Coded Wire Tag Recoveries in Recreational Fisheries
Chinook Life History, Stocking Methods, and Post-Stocking Survival in Lake Huron