struction, increased sedimentation, and possible 

 construction of dams in the future (Yerger 1979). 

 Mettee (1976) mentioned that there has been 

 some interest in damming several of the streams 

 occupied by this darter. 



There are presently 15 impoundments on the 

 drainage system occupied by the Okaloosa darter. 

 Two on Tom's Creek were made by beavers and 

 the rest were made by man. Most of these have 

 produced little effect on darter populations above 

 and below impoundments, but darters are unable 

 to use the reservoir portions. Two eutrophic im- 

 poundments on the portion of Mill Creek flowing 

 through the golf course at Eglin Air Force Base 

 have adversely affected populations below the 

 impoundments, presumably due to higher nutri- 

 ent content, higher temperature, and increased 

 turbidity (Crittenden 1974). 



Some types of habitat alteration such as road 

 and powerline crossings may not permanently af- 

 fect darter populations. Road construction ap- 

 pears to be harmful for a time (due to excessive 

 siltation), but once established, the bordering 

 stream may support an abundant darter popula- 

 tion due to increased sunlight, stimulating aquatic 

 plant growth (Crittenden 1974). 



In one instance (Swift Creek at State Highway 

 285) no specimens of Okaloosa darter were taken 

 following road construction, while the brown 

 darter was abundant; it is impossible to say 

 whether habitat destruction or competition with 

 the brown darter was responsible for the absence 

 of Okaloosa darters at this site (Mettee et al. 

 1976). Right of way clearing for powerlines may 

 be detrimental if exposure of long sections of 

 streams to sunlight raises the water temperature 

 (Crittenden 1974). 



Presently, a new highway bypassing the cities 

 of Niceville and Valparaiso is being constructed; it 

 will bridge Tom's Creek and Turkey Creek. High- 

 way 85 bridging Juniper (Ten Mile) Creek is being 

 converted to four lanes. Okaloosa darter popula- 

 tions are being monitored at these sites by Crit- 

 tenden and Mettee (Mettee et al. 1976). 



PRIORITY INDEX: 



Not assigned. 



DESCRIPTION 



The Okaloosa darter is a slender, small (up to 

 44 mm) perch-like fish with two dorsal fins, 

 rounded caudal fins and a lateral line arched 

 slightly upward with 32 to 37 (usually 34 to 35) 

 lateral-line scales. There are longitudinal rows of 



dark dots along the sides of the body and a series 

 of dark blotches immediately below the lateral 

 line. The body is reddish-brown to yellow-brown 

 becoming lighter on lower sides; the first dorsal 

 fin has an orange-red stripe near the margin. It 

 is distinguished from its nearest relative, the 

 brown darter, by an absence of conspicuous red 

 spots and a nearly complete lateral line. Photo- 

 graphs appear in CoUette and Yerger (1962) and 

 Mettee etal. (1976). 



RANGE 



Okaloosa darters are endemic to a series of 

 five small creeks in Okaloosa and Walton Counties 

 in west Florida that empty into Rocky and Boggy 

 Bayous near the western end of Choctawhatchee 

 Bay: Rocky Creek, Swift Creek, Turkey Creek, 

 Tom's Creek, Mill's Creek and their various tribu- 

 taries (Collette and Yerger 1962, Crittenden 

 1974). 



There are 300 km of streams in which the 

 Okaloosa darter is found with a watershed area of 

 45,730 ha. Approximately 4,860 ha are in private 

 ownership (including cities of Niceville and Val- 

 paraiso); the remainder are located within Eglin 

 Air Force Base (Crittenden 1974). 



The species' former distribution is the same as 

 the present, but it apparently occurred at more 

 sites on the five creeks (U.S. Department of the 

 Interior 1973). 



RANGE MAP 



Distribution illustrated by shading. Detailed 

 map in Draft Recovery Plan (ODRT 1977). 



STATES/COUNTIES 



Florida: Okaloosa, Walton. 



HABITAT 



The Okaloosa darter inhabits small to medi- 

 um-sized (1.5 to 12.2 m wide, 0.15 to 1.2 m deep) 

 clear streams with moderate to swift currents. 

 Substrate is a clean sand with mud or detritus in 

 areas of reduced current. Waters are neutral to 

 slightly acidic. Vegetation may be absent or in 

 scattered patches or clumps. Bulrushes (Scirpus), 

 bog-moss (Mayaca), golden club (Oronttum 

 aquaticum), spatterdock (Nuphar luteum), green 

 algae {Nitella), and pondweed (Potamogeton) are 

 typical plants. Red algae (Batrachospermum) 

 frequently forms thick concentrations (Collette 

 and Yerger 1962). 



