Aquatic Inventories of Three Mountain Lakes in North-Central Idaho, Coeur d'Alene District, Idaho.

Crater Lake is a small, shallow, high mountain, cirque lake located in north central Idaho. The lake was stocked with cutthroat trout fry (Onchorhynchus clarki) in 1969 and 1973. Since 1975, only grayling (Thymallus arcticus) have been stocked. At present, Crater Lake contains a moderate sized population of grayling. Cutthroat trout are no longer present in the lake. The grayling population appears to be from the last two stockings in 1988 and 1990. Usable spawning habitat is absent from the lake system. Aquatic insects and #10 net zooplankton are limited in diversity. The lake water is slightly acidic with low conductivity and alkalinities. The lake is slowly filling from erosion of the steep mountain slopes and warming due to shallow depth and a dark silt bottom. Buman activity around the lake appears to be light.