Nevada Fish & Wildlife Office
Pacific Southwest Region

Independence Valley Speckled Dace
(Rhinichthys oscululus lethoporus)

 
Photo: Independence Valley speckled dace
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Rhinichthys
Species: osculus
Subspecies: lethoporus
Max Length: 4 inches
Weight:  
Lifespan: Less than 4 years
Feed: Small invertebrates, plant material, zooplankton
Habitat: Desert streams & marsh complexes fed by springs
 

Official Status:

Listed as Endangered on October 10, 1989.
 

Life History:

Specific life history data for Independence Valley speckled dace are lacking. In general, speckled dace become mature during its second summer. Spawning usually occurs throughout the summer, with peak activities June and July when water temperatures approach 18 ° C (65 ° F). Males will congregate in small spawning areas where they may clear a small patch of rocks and gravels. Females will deposit eggs underneath rocks or close to the bottom. Once fertilized, the adhesive eggs will hatch in approximately six days. Larval fish remain in the gravel for an additional seven to eight days. Upon emergence (one week later), fry tend to congregate in the warm shallows near large rocks. Later, they move into quiet swampy coves to rear.
 

Distribution and Habitat:

  Generally, speckled dace occur in a wide variety of habitats, ranging from cold streams and rivers with rocky substrates to small thermal springs with silt substrates. Isolation of populations has allowed genetic divergence and resulted in a number of morphologically distinct subspecies. The historic range of Independence Valley speckled dace was not known before European settlement, which resulted in manipulating springs for irrigation purposes. Currently, this subspecies is confined to a series of springs and associated deep pools and shallow marshlands in the Independence Valley in Elko County . It is believed to be derived from an ancestral form of speckled dace similar to the Lahontan speckled dace ( Rhinichthys osculus robustus ) presently occupying the Humboldt River system.
 

Threats:

  Major threats to this subspecies include competition with/predation by non-native fishes including largemouth bass ( Micropterus salmoides ), bluegill ( Lepomis macrochirus ), and possibly, mosquitofish ( Gambusia affinis ). Another recognized threat is alteration of habitat associated with the use of springs for irrigation purposes (e.g., converting natural spring & marsh complexes into impoundments and canals). This has resulted in areas that have been dewatered.
 

 

Last updated: September 28, 2012