Leopard Darter

Percina pantherina

Description

The leopard darter, Percina pantherina, is a small fish (3 in, 8 cm), light olive above and white below. It has dark eyes marked with gold flecks. The distinctive lateral band consists of 10 or 11 circular black spots connected by a fairly faint black band overlaid by an olive-yellow hue. Thirteen squarish blotches form saddles over the sides. The age of individuals can be determined by the prominence and color of the spots and blotches. The sexes are determined by enlarged midventral scales on the breast, which occur only in the males. Jet-black bands extend from the eyes through the nostrils, then begin to diminish. Closely related to the black-side darter (P. maculata ), the leopard darter can be distinguished by its smaller scales.

Behavior

Early literature described the leopard darter as a riffle-dwelling species; more recent studies, however, found that moderately shallow pools are the preferred habitat of adult leopard darters, who may return to the riffles for spawning. Although little is known, biologists believe that the fish feeds on algae and small invertebrates.

Habitat

Adult leopard darters typically are found in pools in streams with relatively steep gradients that drain mountainous or hilly terrain and have rubble, boulder, and bedrock bottoms. They do not appear to inhabit the smaller headwater tributaries, and there is evidence that the species is most successful in intermediate-size streams rather than larger rivers.

Conditions surrounding occupied habitats include forests and farmland. The forests are generally oak-hickory, mixed pine-oak, and longleaf/ slash and loblolly/shortleaf pine. The agricultural areas are chiefly hay fields, cattle pasture, and chicken houses. Any major impact on the Little River system, including the surrounding land, threatens the leopard darter.

Distribution

The leopard darter has been collected only from the Little River basin in southeastern Oklahoma and southwestern Arkansas.

Before 1977, 64 separate collecting efforts from 30 different locations resulted in a count of only 165 leopard darters. The largest population center was in Glover Creek in Oklahoma. Since 1977, the leopard darter has been studied extensively in the Glover Creek drainage, and it appears to be the second most abundant darter species there. There are no current estimates for the size of this apparently stable population, but some observers believe the total population could be as low as 500 individuals.

Threats

A number of dams and reservoirs have been constructed on the Little River system: Pine Creek Reservoir, Broken Bow Lake, DeQueen Reservoir, Gillham Reservoir, and Dierks Reservoir. Only three leopard darters have ever been collected below these reservoirs. Further damming might well be fatal to the species because of its low numbers and restricted distribution. Spring flooding may also affect reproductive success by interrupting spawning and decreasing larval survival.

Impoundments pose the greatest threat to the leopard darter because of dissolved oxygen content, reduced water flow, altered temperature, and the excessive discharge when water is released from the dams. Since only three leopard darters have been collected below reservoirs, and since they do not survive in lakes, the damming of streams has greatly reduced, and continues to extirpate the species from wide ranges of its historical habitat.

Silviculture, a major economic activity in the Little River basin, and the associated road construction, have caused many alterations in the water-shed, including increased turbidity, erosion, and sedimentation in streams. As a result of industrial activity, the incidence of fish kills in the Little River is increasing. In one incident, creosote, flushed from a lumber treatment waste pond into the Cossatot River, poisoned 10 mi (16 km) of stream. Pollution from the use of herbicides, pesticides, and fertilizers on the agricultural lands surrounding some of the habitat threaten the water quality. Several gravel removal operations in the Little River system destroyed habitat and degraded water quality.

Conservation and Recovery

Very little can be done about the impoundments that have resulted from dam construction, and the increased demands for water by agricultural and municipal users, and flood control management may force further reservoir construction, several of which have been proposed. The strategy proposed in the Recovery Plan is to identify the most important populations and work to secure the stability of those habitats. Providing fish passages as part of the construction of new dams will help prevent populations from becoming isolated from each other and confined to waters below the reservoir where they seldom survive. Controlling water flow to provide sufficient depth for reproduction and growth during certain seasons would certainly increase populations.

The U. S. Fish and Wildlife Service has designated habitat critical to the survival of this species to include the main channel of the Little River in both Oklahoma and Arkansas, reaches of Black Fork Creek, the main channel of Glover Creek, including portions of the east and west forks, and the main channel of the Mountain Fork Creek. However, most of the land surrounding the Little River is privately owned, and the cooperation of the land owners is essential for conserving the habitats.

Research into the biology and population dynamics of this species is ongoing.

Contacts

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
Box 1306
Albuquerque, New Mexico 87103
http://southwest.fws.gov/

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

References

Bailey, R. M., H. E. Winn, and C. L. Smith. 1954."Fishes from the Escambia River, Alabama and Florida, with Ecologic and Taxonomic Notes." Proceedings of the Academy of Natural Science, Philadelphia 106:109-164.

Eleyy, R. L., J. C. Randolph, and R. J. Miller. 1975."Current Status of the Leopard Darter, Percina pantherina. " Southwest Naturalist 20(3):343-354.

Miller, R. J., and H. W. Robison. 1973. The Fishes of Oklahoma. The Oklahoma State University Press, Stillwater.