Biologist Adam Kowalski extracted and read coded-wire-tags (CWT’s) from lake trout, in October. CWT’s are microscopic metal tags placed in the snouts of juvenile lake trout at the hatchery. 

Lake trout heads were collected during the spring fishery independent lake whitefish survey conducted by the Alpena FRO. Kowalski also extracted and read CWT’s from lake trout sampled by the Michigan Dept. of Natural Resources.

CWT’s are extracted by cutting lake trout snouts into smaller and smaller pieces until the tag can be seen and removed.  CWT’s are read under a microscope, and each tag’s unique number is recorded.  The tag number, when compared to stocking records, yields information such as stocking location, stocking date, fish age, fish strain, and hatchery of origin.

In total, Kowalski removed and read over 100 tags from approximately 125 heads. Not all adipose clipped lake trout contain CWT’s, because some lake trout shed their tag and some are erroneously fin clipped.  Additional lake trout heads will be received from Bay Mills Indian Community (BMIC), Chippewa Ottawa Resource Authority (CORA), and the Michigan DNR creel program.  These heads will be processed when received.