“Santa Ana sucker”的意思、由来-开放百科全书

The Santa Ana sucker (Catostomus santaanae) is a freshwater ray-finned fish, endemic to California. It is closely related to the mountain sucker and has dark grey upper parts and silvery underparts. It grows to a maximum length of {{convert|25|cm|in|0|abbr=on}}, but most adults are much smaller than this. It feeds on algae, diatoms and detritus on the floor of shallow streams with sand, gravel or cobble bottoms. It is found in only a few streams in southern California, and many of these in the Greater Los Angeles metropolitan area have been restricted to concrete channels. Because of its small area of occupancy and vulnerability, the International Union for Conservation of Nature has rated this fish as "endangered".

Description

The Santa Ana sucker is closely related to the mountain sucker, and quite similar in appearance. Color is dark grey above and silvery-white below; the sides have a faint pattern of darker blotches and stripes. There are distinct notches where the upper and lower lips meet, and the lower lip is narrower in the middle, with only 3 or 4 rows of papillae at that point. The dorsal fins have 9 to 11 rays, while the pelvic fins have 8 to 10 rays. The caudal peduncle is somewhat longish. In contrast to the mountain sucker, the membrane between the rays of the tail fin is pigmented. Length has been recorded up to {{convert|25|cm|abbr=on}}, but less than {{convert|16|cm|abbr=on}} is more typical.

Also like the mountain sucker, it feeds on diatoms, other kinds of algae, and detritus, which it obtains by scraping surfaces such as rocks. It also eats the occasional insect larva, with larger fish observed to consume insects more frequently.

Habitat

These suckers live in smaller (under {{convert|7|m|abbr=on}} wide) permanent streams, with depths from a few centimeters to over {{convert|1|m|abbr=on}}. The water must be cool, but the flow may be variable; they seem to prefer clear water, but tolerate turbidity. Not surprisingly, given their feeding method, they prefer gravel, rubble, and boulder substrates. In 2010, USF&WS issued an expanded CH determination for the Santa Ana Sucker. 75 Federal Register 77962 (December 14, 2010).

Range

The Catostomus santaanae range is extremely restricted; they are native only to the Los Angeles, San Gabriel, Santa Ana, and Santa Clara River systems in Southern California. Populations have been lost from several parts of the rivers, so that they now only live in Big Tujunga Creek in the Los Angeles River Basin, the headwaters of the San Gabriel River in the San Gabriel Mountains in Angeles National Forest in Los Angeles County, parts of the Santa Clara River system in Los Angeles and Ventura counties, and the lower part of the Santa Ana River in Orange County, especially areas with additional water effluent from sewage treatment plants.^[2]

Conservation

Although some stretches of the rivers are 'wild' and protected by being within the Angeles National Forest area of the San Gabriel Mountains, the coincidence of this fish's range and the Greater Los Angeles metropolitan area, and flowing in concrete lined flood control channels, means that it is a species vulnerable to extinction. The International Union for Conservation of Nature has rated this fish as an "endangered species" because of its decreasing area of occupancy and declining population.^[1]

References

1. ^¹{{Cite journal | author = NatureServe | title = Catostomus santaanae | journal = The IUCN Red List of Threatened Species | volume = 2014 | page = e.T4049A2932819 | publisher = IUCN | date = 2014 | url = http://www.iucnredlist.org/details/4049/0 | doi = 10.2305/IUCN.UK.2014-3.RLTS.T4049A2932819.en | access-date = 3 January 2018}}
2. ^{{cite news |url=http://www.latimes.com/local/california/la-me-ln-threatened-suckers-20160822-snap-story.html |title=Environmentalists to sue San Bernardino and Colton over the killing of threatened fish |newspaper=Los Angeles Times |first=Louis |last=Sahagun |date=22 August 2016 |access-date=23 August 2016}}