In May, Fishery Biologist Scott Koproski finished aging lake whitefish fin rays collected during the Lake Huron Lake Whitefish Distribution Study from 2004, 2005, and 2006. 

This study is funded through the Great Lakes Restoration Act, and there are 7 agencies (USFWS, Michigan DNR, OMNR, CORA, Chippewas of Nawash First Nation, Saugeen First Nation, Bruce Power) tagging approximately 15,000 lake whitefish lakewide in each of 3 years to better delineate lake whitefish spawning stocks in Lake Huron. 

Biologist Koproski began aging fin rays from lethal samples collected during the tagging activities by cross-sectioning the fin ray and identifying annuli present within the sample.  The cross-sectioned fin ray is placed on a glass slide, a drop of vinegar is placed on the sample, and then the sample is viewed under a stereomicroscope. 

Two distinct growth patterns are identified using this technique:  broad summer growth and narrow winter growth.  By counting the bands of winter growth, age estimates are obtained from the fin rays.  Biologist Koproski analyzed over 800 fin ray samples collected during this study.