Michigan Department of Conservation
Institute for Fisheries Research Report No.1752, 1968
The Effects of Certain Angling Regulations on Stream Trout Populations
David S. Shetter
Abstract.-Annual fall brook trout population estimates, yearly angler catches, and a large series of scale samples from 1.75 miles of Hunt Creek, Montmorency County, Michigan, for 1950-1965, provided data for assessment of the effects of a fly fishing only restriction (instead of any lure) on the brook trout population. The restriction (in effect during 1955-1959) did not affect the total mortality rate or the population structure of the brook trout. Similar but less precise information was collected from 19. 8 miles of the North Branch of the Au Sable River for brook trout and brown trout during 1960-1967. Here comparative restrictions included "flies-only, " higher minimum size limit (9 inches instead of 7 inches), lower daily creel limit (5 fish instead of 10 fish). Total mortality and angling mortality rates for brook trout were significantly higher in the less restricted stream area; the restrictions had little effect on the brown trout populations.