Least darter (Etheostoma microperca)

Description

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Least darter fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Least darter description

The least darter (Etheostoma microperca) is a small, robust freshwater fish found in North America ⁽³⁾. It has a deep, flattened body, a rounded snout, large eyes and an unscaled breast ⁽⁴⁾. It is olive-brown above and white to yellow on the underside. There is a series of dark blotches along the sides, a distinct black line runs through the snout and eyes, and there is a dark teardrop under the eyes. There is also black spotting on the underside ⁽⁵⁾. 

During the breeding season, the male least darter becomes dark green with iridescent green scales and the dark blotches turn black. The caudal fin and the second dorsal fin become milky white with charcoal grey bands, and the pelvic and anal fins become enlarged and bright orange ⁽⁵⁾.

Size

Length: up to 4.4 cm ⁽²⁾

Least darter biology

Very little is known about the biology and behaviour of the least darter. It spawns from February to late July, with the timing of breeding varying across its range. Females are thought to produce at least three clutches of eggs each breeding season ⁽⁶⁾, and each egg is deposited individually on vegetation ⁽³⁾. The larvae hatch in about six days and reach maturity at a year old. The least darter is thought to live to around 20 months ⁽⁶⁾. 

The least darter feeds on a variety of aquatic invertebrates, with copepods being a particularly important part of its diet ⁽²⁾.

Least darter range

Occurring in the Great Lakes and Mississippi River basins, the least darter is found from eastern Ontario and Minessota, south to Ohio, Indiana, and Illionis, with isolated populations in Missouri, Kansas, Arkansas and Oklahoma ^{(2) (6)}.

Least darter habitat

The least darter most often inhabits quiet, vegetated lakes, headwaters, creeks and small rivers, where it is usually found over mud and sand. This species also occurs in streams, springs and ponds, and it spawns in shallow, weedy areas ^{(2) (6)}.

Least darter status

The least darter has yet to be classified by the IUCN.

Least darter threats

It is not known whether there are any major threats to the least darter.

Least darter conservation

The least darter has not been the target of any known conservation measures.

Find out more

Find out more about the least darter:

• FishBase - Least darter:
  http://www.fishbase.org/summary/speciessummary.php?id=3441

Authentication

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Glossary

Anal fin

In fish, an unpaired fin on the under surface of the fish, behind the anus.

Caudal fin

The tail fin of a fish.

Copepod

A large and diverse group of minute marine and freshwater crustaceans. They usually have an elongated body and a forked tail.

Dorsal fin

The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans (whales, dolphins and porpoises).

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Pelvic fins

In fish, the pair of fins found on the underside of the body.

Spawning

The production or depositing of eggs in water.

References

1. Integrated Taxonomic Information System (ITIS) (July, 2011)
   http://www.itis.gov/
2. FishBase - Least darter (July, 2011)
   http://www.fishbase.org/summary/speciessummary.php?id=3441
3. Smith, P.W. (2002) The Fishes of Illinois. University of Illinois Press, Champaign, Illinois.
4. Simon, T.P. (2011) Fishes of Indiana: A Field Guide. Indiana University Press, Indiana.
5. Goldstein, R.J., Harper, R.W. and Edwards, R. (2000) American Aquarium Fishes. Texas A&M University Press, Texas.
6. NatureServe Explorer - Least darter (July, 2011)
   http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Etheostoma%20microperca