The Niangua darter is a species of fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...

 in the Percidae

Percidae

The Percidae are a family of perciform fish found in fresh and brackish waters of the Northern Hemisphere. The family contains about 200 species in ten genera...

 family. It is endemic to the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is found only in the Niangua River

Niangua River

The Niangua River is a tributary of the Osage River in the Ozarks region of southern and central Missouri in the United States. Via the Osage and Missouri rivers it is part of the watershed of the Mississippi River.-Course:...

 system of central Missouri

Missouri

Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

. It is a federally listed threatened species of the United States.

Life history

Adult Niangua darters move from pools and slow runs to gravel riffles prior to spawning. The spawning season runs from mid-March to early June, but most of the breeding occurs in April. After spawning, Niangua darters return to the pools and stream runs.

Niangua darters can live four or more years, but few survive longer than two years. Young darters reach sexual maturity after one year. Niangua darters eat the nymphs of stoneflies and mayflies and other aquatic insects.

Habitat and distribution

Niangua darters live in clear upland creeks and small to medium-sized rivers with slight to moderate currents. They require continuously flowing streams with silt-free gravel and rock bottoms. These streams typically drain hilly areas with chert or dolomite bedrock. Niangua darters are found most of the year in shallow pools, margins, and stream runs.

Niangua darters occur only in Missouri and are located in counties in the Osage River basin including: Osage, Maries, Miller, Camden, Hickory, Dallas, Benton, Greene, Webster, Cedar, Polk, and St. Clair counties. The Niangua darter was historically widespread and abundant in these rivers and streams.

Cause of Decline

The Niangua darter has declined in numbers during the last 30 years, primarily due to habitat loss from reservoir construction, and stream channelization. Reservoirs isolated populations of Niangua darters and barred them from dispersing between suitable habitats. Land clearing and increased amounts of sediment and nutrients have also caused declines in Niangua darter populations.

Sources

• Gimenez Dixon, M. 1996. Etheostoma nianguae. 2011 IUCN Red List of Threatened Species. Downloaded on 2 September 2011.
• Mattingly, H. T. and D. L. Galat. (2002). Distributional patterns of the threatened Niangua Darter, Etheostoma nianguae, at three spatial scales, with implications for species conservation. Copeia 3 573-585.
• Mattingly, H. T., et al. (2003). Reproductive ecology and captive breeding of the threatened Niangua Darter Etheostoma nianguae. American Midland Naturalist 149(2) 375-83.
• Strange, R. M. and H. T. Mattingly. (1997). Threatened fishes of the world: Etheostoma nianguae Gilbert & Meek, 1887 (Percidae). Environmental Biology of Fishes 49(2) 196.