The Hutton tui chub was listed as threatened in 1985. A recovery plan was published in 1998. There is no critical habitat designation.

Description

The Hutton tui chub is an undescribed subspecies of Gila bicolor, a widespread minnow found in the arid western United States. The Hutton tui chub is robust, with the greatest depth of body immediately behind the head. This subspecies is distinguished from other tui chubs in adjacent basins by morphology of the head. The head has a convex outline, is longer, deeper, and the distance between the eyes is greater than other tui subspecies.

Historic Status and Current Trends

The Hutton tui chub is the only fish found in the Alkali Subbasin in southwestern Oregon. Prehistorically, Alkali Lake likely reached a maximum depth of 82.5 meters (270.7 feet) and covered about 2,331 square kilometers (1,448.4 square miles). Since that time the water level has fluctuated, but with a drying trend. In 1977, the distribution of the Hutton tui chub included only two springs in the Alkali subbasin, Hutton Spring and an unnamed spring. Attempts to find this unnamed spring in 1996 were unsuccessful and this population may have been lost.

Habitat

The Hutton tui chub occurs in Hutton Spring, Lake County, Oregon. The size of the springhole of Hutton Spring varies with excavations made by the owner. It has ranged from 6 meters (20 feet) to nearly 12 meters (40 feet) in diameter, and is about 4.5 meters (15 feet) deep in the center. Hutton Spring is occupied in part by tules (Scirpus americanus). Other vegetation present includes sedge (Carex sp.), saltgrass (Distichlus sp.), and squirreltail (Sitanion hystrix). The fish use the vegetation and whatever debris is present for cover. Some of the larger individuals use the deep spring hole as cover. The recorded water temperature is 64º F. (17.7º C), during the summer (May to October). The outflow from the spring forms a small area of wetland adjacent to the sources. This is occupied by grasses, water parsley, and sedges. The spring is in a grassy area bordered to the north and west by shrubby rangeland and to the east and south by the lake bed of pluvial (rain-influenced) Alkali Lake. A low dry ridge with sagebrush is immediately south of the spring area. Elevation at the site is 1,371.6 meters (4,500 feet).

Reasons for Decline

The isolation of the Hutton tui chub is due to the desiccation of pluvial Alkali Lake. Present status is in part a result of past access by cattle to Hutton Spring. Threats to tui chubs include: pumping of water from the springs, which occurred in the past but is not occurring now; contamination of groundwater by dispersal of chemicals from a herbicide manufacturing residue disposal site 2.8 kilometers (1.75 miles) south of Hutton Spring; and, modification of the springs (via heavy equipment - which in turn causes other problems such as siltation, erosion, vegetation cover loss, water diversion and drawdown).

Conservation Measures

Hutton Spring is privately owned and the habitat is in good condition primarily due to conscientious long-term land stewardship by the landowner. This habitat is currently fenced to exclude cattle and is in stable condition. The Oregon Department of Environmental Quality (DEQ) is currently monitoring groundwater contamination from the chemical disposal site to the south of Hutton Spring. The DEQ has determined that the contaminated plume is spreading from east to west away from Hutton Spring and thus does not currently constitute a threat to the water quality in Hutton Spring.

References

Bills, F.T. 1978. Taxonomic status of the isolated populations of tui chub referred to as Gila bicolor oregonensis (Snyder). MS Thesis, OR State Univ.

Bond, C.E. 1974. Endangered plants and animals of Oregon: I, Fishes., OR Agricultural Experiment Station Special Report 205: 1-9.

Snyder, J.O. 1908. Relationships of the fish fauna of the lakes of southeastern Oregon. Bulletin of the U.S. Bureau of Fish XXVII (1907):69-102.

U.S. Fish and Wildlife Service. 1985. Determination of threatened status for Hutton tui chub and Foskett speckled dace. FR 50:12302-12306.

U.S. Fish and Wildlife Service. 1985. Special rule regarding take of Hutton tui chub and Foskett speckled dace. Federal Register 50:12302-12305.

U.S. Fish and Wildlife Service. 1998. Recovery plan for the native fishes of the Warner Basin and Alkali Subbasin. Portland, Oregon. 86pp.

Waring, G.A. 1908. Geology and water resources of a portion of south-central Oregon. U.S. Geological Survey Water Supply Pop. 220:1-86.