ARKANSAS DARTER - Etheostoma cragini
The Arkansas darter is a small perch. It lives in shallow, spring branches and spring-fed creeks with sandy bottoms and mats of watercress. Their habitat has declined from the impoundment and use of water for agricultural purposes, destruction of stream banks and shallow wetlands, and water pollution near urban areas. The species is listed RARE by the Missouri Department of Conservation and is a CANDIDATE for federal listing by the U.S. Fish and Wildlife Service.
Identification
The Arkansas darter is a small member of the perch family. It has a short, blunt snout with a barely noticeable mouth. Opercles (bony covering protecting the gills) and preopercles (foremost opercular bone) are scaleless. The spiny dorsal fin has 9 or 10 spines and the soft dorsal fin has 11 to 13 rays. The tail fin has two spines.
The Arkansas darter's back is colored with six to eight indistinct dark cross-bars. Its head and body are thickly sprinkled with fine black specks. A narrow dark vertical bar is visible beneath the eye. Adults are commonly 1.6 to 2.2 inches long, to a maximum of about 2.5 inches.
Breeding males show bright orange color along the belly surface and the gills. Females are dark tan with brown-black on the back. Both sexes have 12 to 14 dark bars along the midside, a dark wedge-shaped spot below the eye and the underside is covered with very tiny dark spots.
For a technical description of this fish, refer to:
- Plieger, W.L. 1991. The Fishes of Missouri. Missouri Department of Conservation. Jefferson City, Missouri. 343 pp.
- Robison, H.W. and T.M. Buchanan. 1945. Fishes of Arkansas. University of Arkansas Press, Fayetteville, Arkansas.
Life History
Arkansas darters feed on a variety of aquatic insects and some plant material, including small seeds.Mayflies are the main source of food.
In Missouri, Arkansas darters spawn mid-February to mid-July. Spawning takes place in shallow water over a bottom of coarse gravel. Darters are sexually mature in one year or less. The population in Missouri is dominated by individuals less than two years old, with a maximum age of three years.
Eggs are usually deposited in open areas, on organic material that covers a sandy streambed. Young darters tend to occupy more open areas. Adult darters use areas with more aquatic vegetation.
Habitat and Distribution
Localized populations occur in the Arkansas drainage in eastern Colorado, southern Kansas, northeastern and north-central Oklahoma, southwestern Missouri and northwestern Arkansas. The species is uncommon across its range.
Distribution of the Arkansas darter is shrinking in the western and central parts of the range. It is susceptible to habitat loss resulting from irrigation diversions and through lowering of the water table caused by ground water pumping associated with irrigation and other water uses.
In Missouri, the Arkansas darter is known only from the Spring River system of the southwestern Ozarks. Because of its specialized habitat this darter is spotty in distribution but is often quite common where it does occur.
Arkansas darters live in shallow, clear, usually spring-fed streams with sandy bottoms. They prefer slow currents of cool water, partially overgrown with rooted aquatic vegetation, such as watercress.
Cause of Historic Decline
Surface water diversion and dewatering of the Ogallala Aquifer for irrigation and general development resulted in major losses of Arkansas darter habitat.
Since the late 19th century, the Arkansas darter's habitat has been reduced by the use of water for agricultural purposes, destruction of stream banks and shallow wetlands from livestock grazing and construction activities, and water pollution.
Current Threats to Arkansas Darter
- Habitat loss The biggest threat to the Arkansas darter is loss of habitat as more water is taken from streams and underlying aquifer for agricultural uses. Livestock grazing near streambanks often destroys the vegetation that darters use as protection. Water pollution from erosion and chemical runoff also affect the darter and its habitat.
- Unrestricted sand and gravel removal Removal of sand and gravel from stream bottoms destroys the Arkansas darter's breeding habitat. Disturbance of the streambed can affect the immediate area and also the area downstream by increasing siltation.
- Habitat degradation Agricultural runoff containing chemicals and waste from livestock feedlots decreases water quality. Unrestricted use of streams by cattle increases sediments and organic matter in streams and can destroy fish habitat.
- Natural dispersal Impoundments and reduced stream flows decrease the Arkansas darter's ability to move to new locations. The darter may be forced to remain in areas that are not suitable for them.
Protection and Management: Steps Toward Recovery
- Protect limited existing habitat Arkansas darter habitat should be protected and enhanced. Construction of dams and reservoirs and other watershed alterations should be avoided where possible. Small streams and shallow areas should be maintained for small fish habitats. Construct fences to exclude livestock from streams.
- Sand and gravel removal Follow proper gravel and sand removal procedures outlined in the Missouri Instream Sand and Gravel Removal Guidelines prepared by the Missouri Departments of Conservation and Natural Resources. Guidelines include the following: leave a minimum 20-foot buffer zone between the water line and the excavation area, do not mine within 20 feet of streamside vegetation, and do not alter stream channels. For more information and a copy of the pamphlet, contact: Missouri Department of Conservation Policy Coordination Section P. O. Box 180 Jefferson City, MO 65102-0180
- Habitat improvement Re-establish riparian corridors along streams used by the Arkansas darters to reduce stream erosion. Plant willows and other vegetation in 50-foot wide strips on either side of the stream bank, or exclude livestock with fences and allow the area to naturally revegetate. Establish a tree revetment in areas that are severely eroded.
Written by Charlene M. Bessken
Missouri and federal law prohibits the importation, transportation, sale, purchase, taking or possession of animals on the State or Federal lists.
For more information on the Arkansas darter, or to report sightings of this species, contact:
Endangered Species Coordinator or:
Wildlife EcologistMissouri Department of Conservation
Natural History Division
P.O. Box 180
Jefferson City, MO 65102
573/751-4115
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