|Scientific Name:||Cottus asperrimus|
|Species Authority:||Rutter, 1908|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
Listed as Near Threatened because the species meets some of the criteria for Endangered or Vulnerable; extent of occurrence is very small (less than 5,000 sq km), area of occupancy is small (less than 500 sq km), and abundance may be declining, but the distribution is not severely fragmented, population size likely exceeds 10,000, and the species occurs in more than 10 locations. However, the distribution is limited and threats to habitat remain, so the species could qualify for a threatened category in a relatively short period of time should threats from fire-caused sedimentation or pollution from rice cultivation continue or increase.
|Range Description:||This species is largely restricted to spring-fed tributaries of the Pit River in northeastern Shasta County, California; it is most numerous throughout the Fall River and its major tributary, the Tule River; also occurs in Sucker Springs Creek and lower Hat creek (and associated springs) up to and including the major spring system at Crystal Lake; it is currently rare or absent in the interconnecting reaches of the Pit River, except in the reach immediately below the confluence with Hat Creek; it occurs in run-of-the-river reservoirs on the Pit River, including Britton Reservoir and Tunnel Reservoir (Moyle 2002).|
|Range Map:||Click here to open the map viewer and explore range.|
This species is represented by several occurrences (subpopulations) in a small range. Sixteen occupied areas were found when the range was thoroughly surveyed by Moyle and Daniels (1982).
Total adult population size is unknown but presumably exceeds 10,000. This species is abundant in its small range (Page and Burr 2011).
Populations appeared to be stable as of 1990 (California Department of Fish and Game 1990). Moyle (2002) stated that the future of this species seems reasonably secure with continued protection.
|Habitat and Ecology:||Habitat includes vegetated runs and riffles of (often spring-fed) creeks and small to medium rivers, usually over gravel or sand in cool, clear, fairly deep (up to 1-2 meters) water (Lee et al. 1980, Moyle 2002, Page and Burr 2011).|
|Major Threat(s):||Past management of streams for trout fishing was detrimental due to introduction of predatory brown trout and poisoning to eradicate nongame fish (Moyle 2002). Today, management of Fall River and Hat Creek for wild trout fisheries appears to favour sculpins (Moyle 2002). Hydroelectric development of the Fall and Pit rivers has destroyed or degraded some habitat, whereas a series of reservoirs seems to have been colonized by Rough Sculpins, extending the range downstream by about 22 km (Moyle 2002). Logging, grazing, and fires have led to increased sedimentation into the Fall River, but these threats are being addressed by private landowners and public agencies. Increase in wild rice cultivation has resulted in warm, polluted water entering the Fall River (Moyle 2002). Its future currently seems reasonably secure (Moyle 2002). However, Moyle et al. (2011) put this species in a status category that he regarded as roughly equivalent to IUCN's Near Threatened category.|
|Conservation Actions:||Biology and distribution are well studied. Populations should be surveyed every 5-10 years. Waterways and water quality should be protected in Hat Creek and Fall River.|
|Citation:||NatureServe 2014. Cottus asperrimus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 06 July 2015.|