Clover Valley speckle dace

Rhinichthys osculus oligoporus

SPECIES CODE: E03B V01

STATUS:

Listed Endangered in its entire range (54 FR 41448 41453, 1989 October 10). Recovery plan completed on May 12, 1998.

SPECIES DESCRIPTION:

Clover Valley speckled dace is a subspecies of speckled dace of the Cyprinidae family, whose maximum length rarely exceeds 4 inches. (USFWS 1998)

This species is a diurnal bottom feeder, feeding primarily on small invertebrates (such as aquatic insects), plant material, and zooplankton (floating, microscopic aquatic animals). (USFWS 1998)

REPRODUCTION AND DEVELOPMENT:

Specific reproductive patterns have yet to be examined, however, speckled dace generally mature in their second summer. Spawning usually occurs in the months of June and July at water temperature of 18°C (Sigler and Sigler 1979, Moyle 1976). Eggs are deposited underneath rocks, into spaces in the gravel, or close to the bottom and fertilized (Sigler and Sigler 1979, Moyle 1976). Eggs hatch within a week, and fry remain in the gravel an additional week, and after emerging will congregate in the warm shallows of streams. (USFWS 1998)

RANGE AND POPULATION LEVEL:

Historical range and habitats are unknown. Currently, it is known to occur in Wright Ranch Spring, Bradish Spring, and Clover Valley Warm Springs, Nevada. (USFWS 1998)

HABITAT:

In remaining habitats, this species is found primarily in reservoirs and outflows of the three spring systems: Clover Valley Warm Springs, Wright Ranch Spring, and Bradish Spring. However, habitat requirements and availability are unknown. (USFWS 1998)

PAST THREATS:

The building and manipulation of reservoirs for irrigation was thought to be a serious threat to the Clover Valley speckled dace due to the reduction of available stream/outflow habitat and pond/reservoir habitat when water levels were regulated. Nonnative sport fish prey upon and/or outcompete this species

CURRENT THREATS:

The Clover Valley speckled dace is in jeopardy because of their extremely limited distribution, the sensitivity of their habitats to perturbation by irrigation practices, and introduction of non-native aquatic species.

CONSERVATION MEASURES:

LITERATURE CITED:

Moyle, P.B. 1976. Inland Fishes of California. University of California Press. Berkeley and Los Angeles.

Sigler, W.F., and J.W. Sigler. 1979. Fishes of the Great Basin: A Natural History. University of Nevada Press. Reno.

U.S. Fish and Wildlife Service. 1998. Recovery Plan for the Endangered Speckled Dace of Clover and Independence Valleys (Rhinichthys osculus lethoporus and Rhinichthys osculus oligoporus). Portland, Oregon. 50pp.