Fisheries Research Report No. 1723, 1966

Michigan Department of Conservation
Research and Development Report No. 71
Institute for Fisheries Research Report No. 1723, 1966
Lake Trout Angling on Keweenaw Bay in 1964

Thomas M. Stauffer

      Predation by sea lampreys (Petromyzon marinus) has severly reduced the abundance of lake trout (Salvelinus namaycush) in Lake Superior. The decline began in 1951, and by 1960 their abundance was down to about 10% of its former level. Procedures taken to restore the lake trout population to its former size include poisoning of sea lamprey larvae in streams, banning of commercial fishing for lake trout (effective June 1962), and large-scale stocking of hatchery-reared fish during 1958-1964. Poisoning of larvae began in 1958, and a drastic reduction in the sea lamprey population became apparent in 1962.
      The planting of lake trout has resulted in a localized concentration of these fish in Keweenaw Bay which is attracting an increasing number of anglers. There has been some concern that the catch of lake trout will jeopardize the recovery of the species. A census was taken here in 1964 to obtain an estimate of the sportsmens’ catch and determine whether or not such concern is justified.
      Keweenaw Bay (Fig. 1), located in southern Lake Superior, has water depths mostly of 100 to 400 feet. Its southern end, L’Anse Bay, is between 50 and 100 feet deep. L’Anse Bay is closed to commercial fishing south of Baraga. Falls River, the only important tributary of Keweenaw Bay, enters L’Anse Bay at L’Anse. It has a normal summer flow of 10-30 c.f.s. It receives a spawning run of rainbow trout (Salmo gairdneri) from Lake Superior in the spring, and a spawning run of brown trout (Salmo trutta) in the fall.
      Before 1951, “jigging” (“bobbing”) produced excellent catches of lake trout on Keweenaw Bay, although few fish larger than 18.0 inches were taken. This fishery declined rapidly thereafter until 1962 when the fishing improved markedly. An estimated 1,200 lake trout that averaged about 2 pounds were caught between June 1962 and June 1963. This catch evidently consisted entirely of hatchery trout which had been planted in 1960 and 1961 (Table 1). Most of these fish were caught through the ice in relatively shallow water (less than 100 feet deep) near the mouth of the Falls River, an area formerly unproductive for lake trout. Considerable numbers of rainbow trout, some coregonids, and a few brown trout and northern pike (Esox lucius) also were caught in 1962-63.