Michigan Department of Natural Resources
Fisheries Research Report No.1823, 1975
A Survey of Lake Medora, Keweenaw County, with Special Emphasis on
the Endangered Species of Medora Whitefish
Merle G. Galbraith,, Jr.
Abstract.-The fish management program for Lake Medora in Keweenaw County,, Michigan, has been of special concern to local anglers for some time. During the fall of 1974, a survey of Lake Medora was conducted to evaluate past management practices and to assess the status of the Medora Lake whitefish. It is important now to decide whether the management of this unique and rare species warrants special efforts to preserve it, and to what extent it should receive priority over other game fishes. Data on water temperatures, dissolved oxygen, water transparency, plankton, and fish were collected and compared with data collected during the past 35 years. There was little difference in the summer water temperature and dissolved oxygen content, between 1938 and 1974. However, the volume and species diversity of plankton were much greater in 1974 than in 1938. The zooplankton is a primary source of fish food. Trap nets, fyke nets and experimental gill nets were used to collect fish during the fall spawning activity of the whitefish. The predominant species collected were rainbow trout, whitefish, and yellow perch; the rainbow trout was the most abundant. Net collections indicated that a sizable population of -the Medora whitefish still exists in this lake. The nets took several walleyes which were survivors from a 1971 planting of fingerlings. No minnows or other prey species were collected, nor have they been reported to be present in the lake. Crayfish were abundant, judging from the catch in gill nets. The fish population in Lake Medora currently is in fair balance with its food supply, judging from the numerical abundance, growth, and size-frequency distribution of the predominant fishes, and from the abundance of zooplankton and crayfish. Therefore it is recommended that continued fish plantings be limited to rainbow bout, and not include further plants of walleyes. The lake is not rich enough to support a much greater fish population. Furthermore, as a precautionary measure to avoid overstocking and poor production, the stocking of rainbow trout should be on an every-other-year schedule. Because Lake Medora is one of the few inland lakes in Michigan which contains a self-sustaining population of whitefish, and because this whitefish is currently being considered as an endangered race, the lake should be managed with special consideration for maintaining this stock of whitefish. Periodic netting should be done at least once every 5 years to assess the condition of the fish stocks in the lake.