Santa Ana sucker

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 25 cm (9.8 in), but less than 16 cm (6.3 in) 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.

These suckers live in smaller (under 7 m (23 ft) wide) permanent streams, with depths from a few centimeters to over 1 m (3 ft 3 in). 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).

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]

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]

• "Catostomus santaanae". Integrated Taxonomic Information System. Retrieved 18 April 2006.
• Peter B. Moyle, Inland Fishes of California (University of California Press, 2002), pp. 182–185
• Froese, Rainer and Pauly, Daniel, eds. (2006). "Catostomus santaanae" in FishBase. April 2006 version.