The Santa Ana sucker (''Catostomus santaanae'') is a freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to California. It is closely related to the

mountain sucker The mountain sucker (''Catostomus platyrhynchus'') is a sucker found throughout western North America, on both sides of the Rocky Mountains, including the upper Missouri River, Columbia River, Sacramento River, and Colorado River. It is not li ...

and has dark grey upper parts and silvery underparts. It grows to a maximum length of , but most adults are much smaller than this. It feeds on

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s and

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

on the floor of shallow streams with sand, gravel or cobble bottoms. It is found in only a few streams in southern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, and many of these in the

Greater Los Angeles Greater Los Angeles is the second-largest metropolitan region in the United States with a population of 18.5 million in 2021, encompassing five counties in Southern California extending from Ventura County in the west to San Bernardino Coun ...

metropolitan area have been restricted to concrete channels. Because of its small area of occupancy and vulnerability, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has rated this fish as "

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

Description

The Santa Ana sucker is closely related to the

, 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

papilla Papilla (Latin, 'nipple') or papillae may refer to: In animals * Papilla (fish anatomy), in the mouth of fish * Basilar papilla, a sensory organ of lizards, amphibians and fish * Dental papilla, in a developing tooth * Dermal papillae, part of ...

e at that point. The

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s have 9 to 11 rays, while the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s have 8 to 10 rays. These suckers do have an anatomy variation by sex where females have tubercles on caudal peduncle and anal fin while men have an additional tubercles on lower half of caudal peduncle, anal, and caudal fins. The

caudal peduncle Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

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 , but less than is more typical. Also like the mountain sucker, it feeds on

s, other kinds of

, and

, which it obtains by scraping surfaces such as rocks. It also eats the occasional insect

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

, with larger fish observed to consume insects more frequently. The breading habits of Santa Ana Suckers do not differ from other species of suckers as the female fish are attended by at least 2 male fishes during mating seasons. A female sucker can release between 4,000 and 16,000 eggs amongst her gradual breeding process. Their living patterns consist of being a nonmigrant species that are short-lived with around 4 years of time, on average. Santa Ana sucker conservation (13586703275)

Santa Ana sucker conservation (13586703275)

Habitat

Santa Ana Suckers live in small to medium size streams throughout the year in Southern California. They notably thrive in freshwater conditions. The depths go from a few centimeters to over 1 m (3 ft 3 in). The rivers they swim in are at a cool temperature (average of <22 °C), with variable flow as they are well-adapted to survive in the most-intense flood conditions. 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 Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

, San Gabriel, Santa Ana, and Santa Clara River systems in

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

. Populations have been lost from several parts of the rivers, so that they now only live in

Big Tujunga Creek Big Tujunga Creek is a major stream in Los Angeles County in the U.S. state of California. From its headwaters high in the San Gabriel Mountains, it flows generally southwest for ,U.S. Geological Survey. National Hydrography Dataset high-resolution ...

in the Los Angeles River Basin, the headwaters of the San Gabriel River in the

San Gabriel Mountains The San Gabriel Mountains ( es, Sierra de San Gabriel) are a mountain range located in northern Los Angeles County, California, Los Angeles County and western San Bernardino County, California, United States. The mountain range is part of the Tr ...

Angeles National Forest The Angeles National Forest (ANF) of the United States Forest Service, U.S. Forest Service is located in the San Gabriel Mountains and Sierra Pelona Mountains, primarily within Los Angeles County, California, Los Angeles County in southern Calif ...

Los Angeles County Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the most populous county in the United States and in the U.S. state of California, with 9,861,224 residents estimated as of 2022. It is the ...

, 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 Orange County most commonly refers to: *Orange County, California, part of the Los Angeles metropolitan area Orange County may also refer to: U.S. counties *Orange County, Florida, containing Orlando *Orange County, Indiana *Orange County, New ...

, especially areas with additional water

effluent Effluent is wastewater from sewers or industrial outfalls that flows directly into surface waters either untreated or after being treated at a facility. The term has slightly different meanings in certain contexts, and may contain various pollut ...

from

sewage treatment plant Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...

s. A substantial fish population can also be found in a research-monitored project in Los Angeles County of Haines Creek.

Conservation

Since Santa Ana Suckers have been enlisted as an endangered species (April 2000), the Santa Ana Watershed Project Authority has been actively working towards conservation efforts through direct administrative action and educational opportunities for the public to become aware of. Watershed conservation efforts are key in saving these suckers as their biggest threat posed is of habitat lose where it is recorded that they currently have lost over 95% of their natural habitat. Although some stretches of the rivers are 'wild' and protected by being within the

area of the San Gabriel Mountains, the coincidence of this fish's range and the

metropolitan area, and flowing in concrete lined

flood control channel Flood control channels are large and empty basins which let water flow in and out (except during flooding) or dry channels that run below the street levels of some larger cities, so that if and when a flood occurs, the water will run into these ch ...

s, means that it is a species vulnerable to

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

. The

has rated this fish as an "

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

" because of its decreasing area of occupancy and declining population.

References

* * Peter B. Moyle, ''Inland Fishes of California'' (University of California Press, 2002), pp. 182–185 * {{Taxonbar, from=Q3756653 santaanae Endemic fauna of California Fish of the Western United States Santa Ana River ESA threatened species Fish described in 1908