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Foskett speckled dace

Photo of Foskett Speckled Dace (B. Moran/USFWS)

Scientific name: Rhinichthys osculus ssp.

Status:  Delisted

Critical Habitat: None

Listing:  Foskett speckled dace was recovered and removed from the list of Endangered and Threatened Species, effective October 15, 2019.

Potential Range Map

  • Introduction

    The Foskett speckled dace was listed as threatened in 1985. The listing rule found that the designation of critical habitat was not prudent, as identification of the habitat may have led to vandalism of the small, isolated springs that support the species.  A recovery plan was published in 1998. Due to the successful implementation of the recovery plan, the species' status improved, and on October 15, 2019, the USFWS announced the removal of the Foskett speckled dace from the list of Endangered and Threatened Species.

    Description and Life History

    Foskett speckled dace are an undescribed subspecies of Rhinichthys osculus, small-bodied minnows that have a large geographic range throughout the western North America. Foskett speckled dace has rounded fins, and the caudal fin is moderately forked. The snout is moderately pointed, and overhangs a slightly downturned mouth. The color of its back is dusky to dark olive; the sides are grayish green, with a dark lateral stripe, often obscured by dark speckled or blotches; fins are plain but brown colored.  Breeding males are reddish on the lips and fin bases. This form of speckled dace is related to the speckled dace of Twentymile Creek in the Warner Basin, Oregon, but is distinguished by a shorter lateral line and larger eye. Distinguishing characteristics are: lateral line much reduced, about 15 scales with pores; about 65 lateral line scales; large eyes; dorsal fin set well behind pelvic fin but before the anal fin point of insertion; barbels present on most individuals.

    Foskett speckled dace reach maturity at age 1 year, and spawning occurs between March into July.  Individual fish can live for approximately four years. Young-of-the-year fish appear to prefer shallow marsh habitats, and mature fish prefer open-water and deeper habitats. Presumably, similar to other dace, Foskett speckled dace require rock or gravel substrate for egg deposition.

    Historic Status and Current Trends

    In prehistoric times, the Foskett speckled dace was likely distributed throughout Coleman Lake of the Warner Basin when it held substantial amounts of water. The Warner Basin includes portions of southeast Oregon, northern Nevada, and northern California. The timing of the isolation between the Warner Lakes and the Coleman Lake subbasin is uncertain, although it may have been as recent as 10,000 years ago. As the lake dried, the salt content of the lake water increased. Suitable habitat would have been reduced from a large lake to any spring systems that provided enough habitat for survival. There is currently only one known population of Foskett speckled dace which is found in Foskett Spring, and an introduced subpopulation exists at nearby Dace Spring.

    In the 1970s, researchers recognized the apparent uniqueness of the species, the Foskett Spring habitat, and the potential threats imposed by livestock grazing or alteration of the small spring. The first translocation of Foskett speckled dace into Dace Spring took place in 1979. Very little data is available on population abundance or trends before 1997, and regular population surveys did not begin until 2005. Foskett speckled dace population abundance is closely related to the availability of open-water habitat, which is limited by the encroachment and expansion of aquatic plants and sediment infilling. Since 1997, population abundance has ranged from 780-27,790 adult fish.

    Habitat

    Both Foskett and Dace springs are extremely small and shallow with limited habitat for fish. Foskett Spring originates in a pool about five meters (16.4 feet) across, then flows toward Coleman Lake in a narrow, shallow channel. The source pool has a loose, sandy bottom and is thick with aquatic plants. The spring outflow channel eventually turns into a marsh and finally dries up before reaching the dry bed of Coleman Lake. Dace Spring is about one kilometer (0.6 mile) south of Foskett Spring and is smaller and more choked with plants. A small spring brook flows through two ponds and excavated channels before the outflow terminates in a cattle trough.  At both springs, Foskett speckled dace live in the spring and constructed pools, channels, and shallow marshes.  Fish find cover under overhanging bank edges, vegetation, exposed roots, and filamentous algae.

    Reasons for Decline

    At the time of listing, there was no management plan in place for Foskett speckled dace, nor any ongoing conservation actions.  The restricted distribution of the species greatly exacerbated the impacts of threats to the population or habitat. Groundwater pumping, with resulting lowering of the water table, was identified as a risk to the species and its habitat. Mechanical modification, historically present at Foskett Spring, was seen as a risk to the fragile spring. Livestock were allowed unregulated access to the springs, threatened the quality of the habitat. In addition, the fish were threatened by the potential of nonnative fish introductions or vandalism to the habitat.

    Conservation Measures

    In 1987, the Bureau of Land Management (BLM) acquired and now manages the 65-ha (160-ac) parcel of land containing Foskett Spring and Dace Spring, and fenced 28 ha (70 ac) to exclude livestock from both springs. A recovery plan for the Foskett speckled dace was published in April 1998. Through the coordinated efforts of BLM, Oregon Dept. of Fish and Wildlife (ODFW), and the U.S. Fish and Wildlife Service (USFWS), a number of extensive habitat enhancement projects have occurred to remove vegetation and sediment at Foskett Spring and Dace Spring. These enhancement projects created more open-water habitat, and the number of Foskett speckled dace increased as a result.

    In 2019, post-delisting monitoring plan (PDM) was finalized to outline the monitoring needed to verify that the Foskett speckled dace remained secure from extinction without the protections of the Endangered Species Act. This five-year plan took effect following the delisting in 2019.  

    The Foskett speckled dace is considered a conservation reliant species, as the long-term persistence of the species will require on occasional management. A Conservation Management Plan was finalized in 2015 by the BLM, ODFW, and USFWS, which outlines the ongoing monitoring, management, and enhancement actions needed to ensure the conservation of the species and its habitat.  The monitoring and management described by the conservation management plan will be implemented concurrently with the PDM and continue following the conclusion of the PDM.

    References

    Armantrout, N., and C.E. Bond. 1981. Basin Report: Oregon Lakes. Pp. 14-15. In: E.P. Pister (ed.) Proceedings of the Desert Fishes Council Vol. XII. (12th Symp. 1980).

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

    Deacon, J.E., G. Kobetich, J.D. Williams, and S. Contreras. 1979. Fishes of North America endangered, threatened, or of special concern: 1979. Fish. 4(2):30-44.

    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.

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

    U.S. Fish and Wildlife Service. 2019. Removing the Foskett Speckled Dace From the List of Endangered and Threatened Wildlife. FR (84): 48290-48308

    U.S. Fish and Wildlife Service. 2019. Post-delisting Monitoring Plan for the Foskett Speckled Dace (Rhinichthys osculus ssp.). U.S. Fish and Wildlife Service, Bend Field Office, Bend, Oregon. 22 pp.

     

    Last updated: June 3, 2020

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