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Hutton tui chub

Photo of Hutton Tui Chub (U.S. Forest Service)

Scientific name: Gila bicolor ssp.  

Status:Threatened

Critical Habitat: None

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

Potential Range Map

  • Description

    The Hutton tui chub is an undescribed subspecies of Siphateles bicolor (formerly in the genus Gila), 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.  In addition, pockets along the edge of the scales contain dark melanophores, which create diamond patterns.

     

    Historic Status and Current Trends

    The Hutton tui chub is the only fish found in the endorheic 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 prehistoric times, the water level of the lake has fluctuated, but with a drying trend.

    Few surveys have been conducted to monitor the status of the species. In 1977, the distribution of the Hutton tui chub included two small springs: Hutton Spring and 3/8 Mile Spring. Population abundance estimates were most recently obtained in 2007, and estimated 959 adult fish in Hutton Spring and 87 adult fish in 3/8 Mile Spring.  A visit to the spring in 2010 confirmed that fish were present in Hutton Spring and 3/8 Mile Spring, but no population estimates were obtained.

    Habitat

    The Hutton tui chub occurs in Hutton Spring and 3/8 Mile Spring, located on private lands in Lake County, Oregon. The area of Hutton Spring varies with excavations made by the owner. Geologic surveys completed in the late-19th century documented the presence of Hutton Spring, and that it had been enlarged from 0.6-1.1m² (6.5-11.8 ft²) to 133 m² (1432 ft²) to ease the watering of livestock. In surveys conducted in 1977, it was noted that Hutton Spring had been recently excavated to remove vegetation, and was 113 m² (1216 ft²).  The first documentation of 3/8 Mile Spring was in 1977, and the spring was 8.6 m² (93 ft²).  In 2007, vegetation infilled shallow margin habitats, and Hutton Spring was 36 m² (388 ft²) and 3/8 Mile 2 m² (22 ft²).  Maximum water depth at Hutton Spring and 3/8 Mile Spring is approximately 2.1 m (6.9 ft) and 0.35 m (1.2 ft), respectively. The dominant vegetation at Hutton Spring and 3/8 Mile Spring is bulrush (Scirpus americanus), but sedge (Carex sp.), saltgrass (Distichlus sp.), and squirreltail (Sitanion hystrix) are also present. The fish use the vegetation and vegetative debris as cover. Some of the larger individuals use the deep spring hole at Hutton Spring as cover. Annual water temperature was measured between 2005 and 2007, and averaged 14.3°C (57.7°F) with a range of 8.2-16.8°C (46.8-62.2°F).  Temperatures are stable, with daily fluctuations less than 1°C (1.8°F). The outflow from Hutton 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. Hutton Spring is fenced to exclude livestock access. Elevation at the site is 1,371.6 m (4,500 ft).

    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.

    The recovery plan for Hutton tui chub outlined objectives for long-term conservation, but did not identify specific criteria for eventual delisting. In 2019, the USFWS amended the recovery plan by modifying two existing conservation objectives into recovery criteria to signal when threats to the species have been potentially ameliorated and delisting may be warranted: 1) Hutton tui chub exist in both Hutton and 3/8 Mile springs and reproduction is evident through the existence of multiple age-classes of fish, 2) long-term protection and management of Hutton Spring and 3/8 Mile Spring, including spring source aquifers, spring pools, and outflow channels, and the immediate area surrounding the springs, is ensured.

    References

    Bills, F.T. 1977. 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.

    Scheerer, P.D. and S.E. Jacobs. 2005. Hutton Spring tui chub and Foskett Spring speckled dace investigations. Oregon Department of Fish and Wildlife, Salem, Oregon. 10 pp.

    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.

     

    Last updated: February 25, 2020

     

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