Okaloosa Darter

Etheostoma okaloosae

Description

The Okaloosa darter, Etheostoma okaloosae, is a small fish with a divided dorsal fin, a rounded tail, and a slightly arched lateral line. This perch-like species' scales have darkly pigmented centers, giving an impression of long rows of spots. The cheek, throat, and chin are brown to yellowish brown with an olive-green cast ventrally and posteriorly. Along both sides there are usually a row of dark blotches. The first dorsal fin has an orange-red stripe near the outer margin and the tail itself usually has vertical bands of alternating light and reddish brown. The fish ranges from 3-4 in (7.5-10 cm) long. Fins are large and transparent.

Behavior

The Okaloosa darter feeds on aquatic insects and plant matter. Its primary spawning period is generally in late April or early May. The eggs are large in comparison to other Percidae. Males first establish territories, and females that enter the territories are mated. There does not seem to be a specified number of females for which males will spawn.

Habitat

The Okaloosa darter is an opportunistic species, in that it inhabits a variety of habitats within streams from sluggish, heavily vegetated areas to swift-flowing stretches over a sandy bottom. It seems to be most numerous in portions of the streams where currents are moderately swift and the depth of water is no more than 5 ft (1.5 m). Water temperatures range between 45 and 75°F (7 and 24°C). Much of the watershed drains pine and scrub oak, sand-hill habitat.

Distribution

The Okaloosa darter was first described in the 1940s from specimens taken from Little Rocky Creek in Okaloosa County. It is considered endemic to six Choctawhatchee Bay tributaries in Okaloosa and Walton counties in the Florida Panhandle. This watershed comprises nearly 113,000 acres (43,730 hectares), most of which falls within Eglin Air Force Base. Only about 12,000 acres (4,860 hectares) are privately owned.

This darter is found along about 190 mi (305 kilometers) of six stream systems flowing from Eglin Air Force Base through or near the cities of Niceville and Valparaiso into Boggy and Rocky Bayous on Choctawhatchee Bay, in Okaloosa and Walton counties, Florida. The habitat involves the main stems and tributaries of Tom's, East Turkey, Mill, Swift, and Rocky Creeks.

The U. S. Fish and Wildlife Service (FWS) has determined that the population has stabilized and is no longer in serious decline, according to a 1997 Revised Draft Recovery Plan. The major responsibility for recovery of this species is with Eglin Air Force Base, which manages most of its known habitat.

Threats

The Okaloosa darter population has declined because of deterioration and loss of habitat, caused by road and dam construction, and siltation from land clearing. In addition, this species has suffered in competition with the more common brown darter, which has moved into headwaters formerly occupied exclusively by the Okaloosa darter.

Conservation and Recovery

Personnel from Eglin Air Force Base, the Florida Game and Freshwater Fish Commission, the Alabama Biological Survey, Florida State University, and the FWS collaborated on production of the 1981 Recovery Plan for the Okaloosa darter, which identified four primary recovery goals: to determine biological characteristics; protect extant populations and habitats; increase population sizes; and reestablish the species throughout its former range. In 1997, that plan was revised to reflect the success of the original plan: Studies recommended in the 1981 Recovery Plan have been completed, and Eglin Air Force Base is implementing habitat conservation measures, and plans to implement others.

Okaloosa darter populations have apparently stabilized. Downlisting this species from endangered to threatened could be considered in 2001 if Okaloosa darter populations in all six inhabited stream systems remain stable or increase, and if effective interagency agreements are established to protect the quality and quantity of water in these streams. Complete delisting may be considered when populations in all stream systems remain stable or increase for 20 years, and when effective and apparently permanent cooperative agreements to protect stream water quantity and quality have functioned for several years.

Contact

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Reference

Crews, R. C. 1976. "Aquatic Baseline Survey on Selected Test Areas on Eglin Air Force Base Reservation, Florida." Report No. AFATL-TR-76-4. Eglin Air Force Base.