Production, fishing intensity, and availability of walleyes (Stizostedion vitreum vitreum) fluctuated widely in the commercial fishery of northern Green Bay in 1929-57. The catch ranged from 16,000 pounds (8 percent of average for the 1929-53 base period) in 1942 to 1,294,000 pounds (633 percent) in 1950. The index of fishing intensity ranged from 17 (1941) to 400 (1950) and that of abundance from 47 (1929) to 222 (1955). Production and fishing intensity were consistently above average in 1947-57; abundance exceeded the average in 8 of these years. The fishery statistics and records of age and size composition of commercial landings of walleyes in the spring and fall fishing seasons of 1949-58 (scale samples were taken from a total of 1,631 fish) were the basis for a study of recent changes in the walleye fishery with particular reference to the effects of fluctuations in the strength of year classes. The 1943 year class, by a wide margin, exceeded all others in the estimated total number (1,173,000 fish) and weight (3,355,000 pounds) contributed to commercial landings. This year class was a major factor in the sharp rise in production and abundance after 1945 and the all-time record catch of 1950. In contrast, certain other year classes (1945, 1946, 1948) have contributed totals as small as 16,000 to 52,000 pounds. The abundance of the 1950, 1951, and 1952 year classes approached or exceeded that of the 1943 year class at the lesser ages (through the IV group), but these more recent classes disappeared from the fishery so rapidly that their total contributions were relatively low. The indicated increase of mortality in the middle 1950's cannot be attributed to increase in the rate of commercial exploitation. Evidence is offered that the heightened mortality rate resulted from expansion of the sport fishery.