For years the commercial fishermen of southern Green Bay contended that the minimum length of 8 inches for yellow perch in that are should be reduced because (1) the perch population was stunted, incapable of reaching the size of 8 inches in any numbers, and (2) the larger perch tended to desert the southern part of the bay after spawning in may. To throw light on this perennially controversial problem, the Fish and Wildlife Service and the Wisconsin Conservation Department in 1948 initiated a cooperative program of study which included the marking of roughly 10,000 to 30,000 spawning-run perch annually, 1948-51, and the investigation of the age and size of fish taken in commercial nets. In general, the views of the commercial fishermen were substantiated.