Michigan Department of Natural Resources Fisheries Technical Report No. 97-1, 1997

Use of Floy Tags to Determine Angler Harvest of Brown Trout in Two Southern Michigan Streams

Michael P. Herman Jackson District Office 301 Louis Glick Highway Jackson, Michigan 49201

Abstract.–In late March 1991, fifty percent of yearling brown trout stocked into the St. Joseph-of-the-Maumee River and sixty-three percent of those stocked in the South Branch of the Kalamazoo River were marked with Floy tags in an effort to estimate angler harvest. St. Joseph River anglers returned a total of 31 tags representing an estimated minimum harvest of 1.8% and Kalamazoo River anglers returned a total of 38 tags, representing an estimated minimum harvest of 1.6%. Factors that could have contributed to the observed low number of tag returns include; tag loss (or shedding) after stocking, high hooking mortality of sublegal tagged fish, mortality due to tagging, natural mortality of tagged trout before they reached legal size, tags not returned by anglers and migration of fish out of the stocked areas. Tag loss and migration of stocked trout was probably very high throughout this study. Thus, angler returns of Floy tags did not yield reliable estimates of angler harvest. These estimates have limited value since they are based on a small number of returned tags and harvest was likely underestimated. Using larger trout may result in improved tag retention and is recommended for future tagging studies.

Fisheries Technical Report No. 97-1 - Full Text Acrobat Reader File.