The sharpnose shiner (''Notropis oxyrhynchus'') is a species of

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 ...

in the family

Cyprinidae 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 verte ...

, the carps and minnows. It is

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 ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the United States, where it is limited to the upper

Brazos River The Brazos River ( , ), called the ''Río de los Brazos de Dios'' (translated as "The River of the Arms of God") by early Spanish explorers, is the 11th-longest river in the United States at from its headwater source at the head of Blackwater Dr ...

basin.Species Assessment and Listing Priority Assessment Form: ''Notropis oxyrhynchus''.
USFWS. April 15, 2011. In 2013 it became a candidate for federal listing 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 ...

of the United States.

Description

This is a slender minnow generally measuring 3 to 5 centimeters in length at maturity, but it is known to reach 9.5 centimeters.Froese, R. and D. Pauly. (Eds.
''Notropis oxyrhynchus''.
FishBase. 2011. It is silver with a faint line extending from the

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s to the tail. The snout is pointed.

Distribution

Today the fish occurs mainly in the upper Brazos River system above Possum Kingdom Lake, it is rarely observed below this

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

and may be extirpated from most or all of the tributaries in the lower river system. Populations are extirpated from the

Wichita River The Wichita River ( ), part of the Red River watershed, lies in north-central Texas. Rising in northeastern Knox County at the confluence of its North and South Forks, the river flows northeast across Baylor, Archer, Wichita, and Clay count ...

, which represented nearly 70% of the known former range of the species. In the upper Brazos it is still a common species.

Biology

This

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels of s ...

inhabits medium and large rivers, channels, and pools. It can be found in shallow, turbid waters over sand and mud substrates. The fish feeds on aquatic and terrestrial invertebrates, including flies, caddisflies,

bugs Bugs may refer to: * Plural of bug Arts, entertainment and media Fictional characters * Bugs Bunny, a character * Bugs Meany, a character in the ''Encyclopedia Brown'' books Films * ''Bugs'' (2003 film), a science-fiction-horror film * ''Bugs ...

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s, odonates, and

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

s. It consumes large amounts of sand and sediment, suggesting that it forages on the riverbed. It may also consume some plant material.Marks, D. E., et al. (2001)
Foods of the smalleye shiner and sharpnose shiner in the Upper Brazos River, Texas.
''The Texas Journal of Science'' 53(4), 327-34. Its life history is not well documented.

Conservation

Several threats have contributed to the decline of the species. Inflow from

s has altered the physical and biological characteristics of the river system, such as temperature, flow patterns, and turbidity, and have contributed to

habitat fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...

and other changes to the ecosystem. The Possum Kingdom, Granbury, and Whitney Reservoirs have produced changes in the aquatic faunal communities of the Brazos River. The construction of more reservoirs is expected to prevent the fish from recolonizing habitat where it is now absent. The invasive plant

salt cedar The genus ''Tamarix'' (tamarisk, salt cedar, taray) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may refer to the Tam ...

(''Tamarix'' spp.) has become abundant along the Brazos River, its spread aided by the construction of reservoirs. The plant likely increases sedimentation and alters water flow, making parts of the habitat unsuitable for the fish. The Brazos River is a relatively saline river because of the salts in the surrounding land and a salty

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

beneath, and the fish is adapted to the saline waters. There is increasing interest in

desalination Desalination is a process that takes away mineral components from saline water. More generally, desalination refers to the removal of salts and minerals from a target substance, as in Soil salinity control, soil desalination, which is an issue f ...

of the river water for municipal use. Planned desalination projects include the construction of wells, pipelines, evaporation ponds, and reservoirs for water treatment. These projects, as well as ongoing wastewater and agricultural

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock market ...

, are expected to alter water and habitat quality.

Gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

and sand mining have produced significant effects on the lower Brazos, but their specific impacts on the fish are not clear. Algal blooms may also affect the species, but evidence is not yet available.

References

{{DEFAULTSORT:shiner, sharpnose sharpnose shiner Endemic fauna of Texas sharpnose shiner Taxonomy articles created by Polbot ESA endangered species

Description

Distribution

Biology

Conservation

See also

References