Muskellunge (Esox masquinongy) are believed to have been one of the original dominant species in the Kawartha lakes fishery of southcentral Ontario. Historically, muskellunge have sustained both commercial and recreational fisheries. Creel surveys conducted by the Kawartha Lakes Fisheries Assessment Unit suggest that each of the Kawartha lakes sustains several thousand hours of muskellunge angler effort and catches of up to 1800 fish annually. Muskellunge angling success during the summer (June – August) fishery ranges from 0.01 to 0.09 fish per angler hour. Sizes of muskellunge from the Kawartha lakes are generally smaller than from other large muskellunge fisheries elsewhere in southern Ontario. Although muskellunge numbers have probably declined since the turn of the century, the Kawartha lakes still provide high quality muskellunge fisheries. Potential impacts resulting from the recent invasion of northern pike (Esox lucius) will be closely monitored.