Fish Slough

A portion of this slough has been designated as a sanctuary for the endangered Owens pupfish, Cyprinodon radiosus, and other native Owens Valley fishes. This pupfish, much of whose habitat has been eliminated by the drainage and drying of marshy areas through the export of water and which has been eliminated from other parts of its remaining habitat due to predation from introduced largemouth bass and competition from mosquito fish, was originally found in the valley from Lone Pine north to this slough. It prefers still or slow-moving water with some vegetation and is now confined to several small areas in Fish Slough and to a small pond some miles to the south. If compatible, the endangered Owens tui chub, Gila bicolor snyderi, will be transplanted to this sanctuary as will the endangered Owens sucker, Catostomus tumeiventris. Some of these may be in the area at present.

In the marsh, extensive areas are covered with bulrush, Scirpus sp., and/or cattails, Typha, sp. At the northern end there are some willows, Salix sp., and cottonwoods, Populus fremontii. The vegetation in the buffer zone is the shadscale scrub community.

The slough is fed by several small springs at the northern end. It follows a shallow valley some13 kilometers (8 miles) on the eastern edge of the volcanic tableland to enter the Owens River some 6 kilometers (4 miles) north of Bishop. The volcanic tableland is composed of Bishop tuff, an early Pleistocene accumulation of rhyolitic pyroclastic rocks. The springs are fed from ground water flowing from the northwest being forced to the surface along the west side of the Fish Slough fault escarpment, which traverses the area.

Integrity: The slough has been essentially unaffected by the water export activities. Most of the area is in government ownership and it is managed to protect and preserve the fish population. A dirt road follows the western margin of the slough. A fish barrier has been installed to prevent introduction of exotic species. The area is fenced.

Use: Research, observation. For information contact California Department of Fish & Game, Bishop, California 93514.

Ref: Wilier, R. R. and E. P. Pister, 1971. management of the Owens Pupfish, Cyprinodon radipsus, in Mono County, California. Transactions of the American Fisheries Society, Vol. 100, No. 3 (July) p. 502-509 (Bibliography).

California Department of Water Resources Bulletin No. 126, 1961. Fish Slough Dam and Reservoir. Sacramento, California.

January 1975