The splittail (''Pogonichthys macrolepidotus''), also called Sacramento splittail, is a

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ver ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

native to the low-elevation waters of the Central Valley in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. It was first described by William O. Ayres in 1854. It is the sole living member of its genus, the Clear Lake splittail ''P. ciscoides'' having become extinct in the 1970s. The distinctive feature of the splittail is the larger upper lobe of the tail fin. It also has tiny

barbels In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some s ...

at the corners of the mouth. The dorsal fin has 9-10 rays, while the pectoral fins have 16-19 rays, the pelvic fin 8-9 rays, and the anal fin 7-9 rays. Color is silver on the sides, with a dusky olive gray on the back; during the breeding season the fins pick up a red-orange tinge, and the males become darker and develop white tubercles on the head and at the bases of the fins. They feed on bottom-dwelling invertebrates and detritus, generally in areas of low to moderate current. In Suisun Bay,

opossum shrimp Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in ...

(mostly ''Neomysis mercedis''), amphipods such as '' Corophium'', and copepods are favorite foods, while in the

Sacramento Delta ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento C ...

they eat clams, crustaceans, and insect larvae. During periods of high water levels (February/March), splittails will move into flooded areas to look for

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. T ...

s. The Sacramento splittail utilizes floodplain habitat for feeding and spawning, and depends upon floodplain habitat for spawning..

Range

Their range is the lower-elevation waters of the Central Valley, extending to San Francisco Bay. Although once found as far north as Redding, they are now only rarely seen in the upper Sacramento River. They were once caught from southern San Francisco Bay and in Coyote Creek (

Santa Clara County Santa Clara County, officially the County of Santa Clara, is the sixth-most populous county in the U.S. state of California, with a population of 1,936,259, as of the 2020 census. Santa Clara County and neighboring San Benito County together f ...

), but are now restricted to the

Sacramento Delta ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento C ...

, Suisun Bay, and the lower parts of

Sonoma Creek , name_etymology = , image = Beaver Dam Sonoma Creek, Sonoma Thanksgiving 2009.jpg , image_caption = Beaver dam on Sonoma Creek at Maxwell Farms Regional Park in Sonoma, California, 2009 , image_size = 300 , ma ...

Petaluma River The Petaluma River is a river in the California counties of Sonoma and Marin that becomes a tidal slough for most of its length. The headwaters are in the area southwest of Cotati. The flow is generally southward through Petaluma's old town, ...

and

Napa River The Napa River is a river approximately long in the U.S. state of California. It drains a famous wine-growing region called the Napa Valley, in the mountains north of the San Francisco Bay. Milliken Creek and Mt. Veeder watersheds are a few ...

. They are tolerant of moderate levels of salinity and/or alkalinity.

Status

Splittail were reclassified as a species of special concern by the U.S. Fish and Wildlife Service on September 22, 2003 from their prior classification as threatened due to litigation. In 2010, the FWS found that the splittail did not warrant listing under the Endangered Species Act.U.S. Fish and Wildlife Service, Bay-Delta Fish and Wildlife Office. Sacramento Splittail https://www.fws.gov/sfbaydelta/EndangeredSpecies/Species/Accounts/SacramentoSplittail/SacramentoSplittail.htm The Central Valley's system of sloughs and backwaters maintained by annual flooding has greatly changed. The cause of the decline of this species is under investigation. IUCN previously classified the splittail 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 in ...

, but the status was downgraded to

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

in 2013.

References

* Peter B. Moyle, ''Inland Fishes of California'' (University of California Press, 2002), pp. 146–150 {{Taxonbar, from=Q2123607 Pogonichthys Endemic fauna of California Fish of the Western United States Freshwater fish of the United States Natural history of the Central Valley (California) Fish described in 1854