Green Bay National Fish and Wildlife Conservation Office biologists Ted Eggebraaten and Dale Hanson, with assistance from volunteer Kevin Corcoran, a student at the Fox Valley Technical College, have completed processing over 1,100 coded-wire tagged lake trout collected from Lake Michigan in 2007. 

The tags, known as CWTs, were implanted into lake trout juveniles prior to their release from Fish and Wildlife Service hatcheries.  Tagged juveniles also receive an adipose fin clip to externally identify CWT marked fish.  Each CWT contains a code that, once deciphered, enables managers to determine the age, strain, stocking location and stocking event for the fish. 

The Green Bay NWFCO serves as the Lake Michigan repository for CWTs and accepts lake trout heads from state and tribal agencies’ commercial, sport, and assessment monitoring programs.  The Service serves an important role in providing states and tribes with CWT data.  This task is consistent with the Service’s objectives of providing management assistance and enables the Service to ensure the CWT marking data are available for evaluation of lake trout rehabilitation goals.