Fish Lake (196) (Harney)

Reachcode: 17120003000620 | Area: 19.2 acres | Shoreline: 0.7 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985)  Fish Lake is a small, remote alpine lake located high on the west slope of Steens Mountain in southeast Oregon. Steens Mountain was heavily glaciated during the Pleistocene Epoch and the landscape at higher elevations clearly shows the imprint of this activity. Several small lakes, of which Fish Lake is the largest, exist in depressions scoured out by the ice. The depressions are closed at their lower ends by glacial moraines, which impounded surface runoff to form the lakes. Fish Lake thus sits at the head of Fish Lake Valley, a classic U—shaped glacial trough. Its small drainage basin is relatively undisturbed and covered with alpine grasses and deciduous trees. Although it is only 16 acres in size, Fish Lake is nevertheless the largest mountain lake in the entire Malheur Lake Basin and for this reason attracts fishermen and campers from a large area. It is stocked annually with rainbow trout and has some eastern brook trout from previous stocking; lots of fish are caught. The Bureau of Land Management has developed a nice recreation area with campsites and picnic sites on the shoreline.

The lake basin has a simple oval shape, and the greatest depth (30 feet) is located near the center. It is well sheltered from the wind and the water develops a pronounced thermal stratification. When visited in the summer of 1982, it was observed that the surface water was sufficiently transparent for light to penetrate below the thermocline, resulting in significant plant growth and a mild oxygen supersaturation in the hypolimnion. In other years, surface blooms of algae have reduced water transparency and there has been a corresponding oxygen deficit in the hypolimnion. This variation in the oxygen concentration in the hypolimnion is somewhat surprising for a lake located in an alpine setting. The concentrations of phosphorus and chlorophyl are also higher than would be expected. It appears that permeable soils around the lake permit seepage of nutrients from the many pit toilets at the camp sites. This cultural contribution to nutrient input has probably caused a decline in water quality of the lake and thereby stimulated a fairly productive food chain. Based upon phosphorus and chlorophyl concentrations and the variable oxygen supply, Fish Lake is classified as mesotrophic.