Niangua darter

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Niangua darter
Etheostoma nianguae.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Percidae
Genus: Etheostoma
Species: E. nianguae
Binomial name
Etheostoma nianguae
C. H. Gilbert & Meek, 1887

The Niangua darter (Etheostoma nianguae) is a species of darter endemic to the eastern United States. It is found only in the Niangua River system of central Missouri. It is a federally listed threatened species of the United States.

Description[edit]

The Niangua darter is a slender, silvery-brown fish with about ten vertical dark bars with brown centers alternating with orange undulating lines. There are two small black spots at the base of the tail fin. The color is accentuated in breeding males which have bright orange and green bars along the flank and orange and green bands on the dorsal and tail fins. The maximum size of this fish is about 13 cm (5 in) but a more common size is 7.3 cm (3 in).[2]

Lifecycle[edit]

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.

Distribution and habitat[edit]

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

Cause of decline[edit]

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. As a consequence of these factors, the IUCN has listed this fish as being "Vulnerable".[1]

References[edit]

  1. ^ a b NatureServe (2013). "Etheostoma nainguae". IUCN Red List of Threatened Species. Version 3.1 (3.1). International Union for Conservation of Nature. Retrieved November 22, 2013. 
  2. ^ " Etheostoma nianguae Gilbert & Meek, 1887: Niangua darter". FishBase. Retrieved 2013-12-26.