Angling and trout population data are compared from two stream sections of the North Branch of the Au Sable River which were fished for alternate 3-year periods of normal regulations (7-inch size limit, 10-trout creel limit, any lure) and special regulations (9-inch size limit, 5-trout creel limit, artificial flies only). Results were: (1) Fishing pressure was reduced by 50% in special regulation sections. (2) Total catch of fish in the creel was reduced by elimination of fish between 7 and 9 inches. (3) Total catch of fish larger than 9 inches was not increased. (4) The catch per hour of fish larger than 9 inches was increased significantly in one special-regulation section, but fewer anglers were involved. (5) Postseason populations of adult trout were greater under special regulations, but nonangling mortality between seasons lowered these gains to normal levels; higher postseason adult populations did not increase reproduction significantly. (6) Trout larger than 16 inches were observed in the catch from normal waters as often as from the special waters. (7) Stream sections fished under normal rules provided the greatest total harvest in the creel and the greatest angler use.