The leopard darter is a small freshwater fish in the perch family (Percidae). This species is endemic to the Little River Basin of southeast Oklahoma and southwest Arkansas, and has always been reported as rare. Since the 1970s, several ichthyologists familiar with the species recommended providing special protection to the leopard darter, as documented by R.R. Miller in 1972, D.G. Cloutman and L.L. Olmstead in 1974 and several others. The leopard darter was listed as a threatened species under the Act on January 27, 1978 (43 FR 3711), and several areas within the Little River drainage basin were designated as critical habitat at that time.
The leopard darter typically inhabits pools that have predominantly rubble and boulder substrates with current velocities that are less than 48 centimeters per second, as documented by R.N. Jones in 1984 and confirmed by M. Lechner and others in 1987. While these fish have been documented in the 1980s by R.N. Jones and others as preferring water depths of 20 to 102 centimeters, recent joint U.S. Fish and Wildlife Service - U.S. Forest Service surveys have shown otherwise. Conducted annually over the span of 10 years, researchers have observed leopard darter at depths of more than 4.0 meters. Leopard darters inhabit pools from June through early February. However, during the spring and winter, riffles and runs maybe used, particularly during the February through April spawning season.
A dense growth of trees and underbrush covering a large tract.
A natural body of running water.
Areas where ground water meets the surface.
Darters feed on small, benthic organisms, as documented by L.M. Page and M. Swofford in 1984. L.M. Page also noted in 1983 that darters are typically first and second-order carnivores that feed mainly on micro-crustaceans as juveniles and on immature aquatic insects as adults. Examination of published literature indicates that considerable dietary overlap may exist between leopard darters and other sympatric Percina species, meaning that are related and in the same geography. For example, dietary preferences of logperch (P. caprodes) and channel darters (P. copelandi) in the main channel Glover River consisted largely of dipterans (chironomids) and ephemeropterans, as documented by R.N. Jones and O.E. Maughan in 1987. Mayfly nymphs (Ephemeroptera: Baetidae and Heptageniidae), blackfly larvae (Diptera: Simuliidae) and midge larvae (Diptera: Chironomidae) were the only food items found in stomachs of 19 leopard darters examined by P.W. James and others in 1991. Blackfly larvae Simulium sp. and mayfly Pseudocloen spp. nymphs were the major food items in seven leopard darter stomachs examined by H.W. Robison in 1978. A 2006 study by L.R. Williams and others, which examined leopard darter food habits from 1994 to 1997, found Baetidae, Chironomidae and Heptageniidae to be the most common families of aquatic insects found in leopard darter stomachs.
Detailed information about feeding behavior, such as time of feeding, feeding intensity or seasonal shifts in feeding patterns is not available for the leopard darter. However, darters as a group, have keen vision and are likely to be diurnal, visual feeders, noted Mathur in 1973 and later, L.M. Page in 1983.
Although the leopard darter is considered an annual species, which means that individuals typically spawn only once in its lifetime, in rare cases some will spawn a second season, as documented by P.W. James and others in 1991. Leopard darters migrate from pools to riffle tailwaters in search of suitable spawning habitat during February and early March when water temperatures reach 10 to 12°C, as also documented by P.W. James in 1988 and again in 1989 with O.E. Maughan. Spawning occurs from mid-March through mid-April on riffles at water temperatures of 12 to 17°C, as P.W. James also noted in 1988. The non-adhesive, demersal eggs are buried in patches of fine gravel, that is 3 to 10 millimeters in diameter, at water depths of 30 to 90 centimeters and current velocities of 10 to 35 centimeters per second, as documented by P.W. James in 1988 and later in 1989 with O.E. Maughan. Eggs hatch in about seven days at 20°C, and larvae presumably drift downstream into pools, as P.W. James noted in 1989.
In 1978, the number of mature and immature ova that H.W. Robison examined in seven specimens varied from 260 to 2,302. P.W. James, and others in 1991, examined five preserved specimens and found that distinguishable ova varied from 294 to 757, with a mean of 465 ova per female. Observations of spawning females in captivity by P.W. James and others in 1991 indicated that clutch size averaged 58.5 and fertilized, water-hardened eggs had a mean diameter of 1.4 millimeters. P.W. James also documented in 1989 that all spawning individuals appeared to be one year of age, with a high mortality of these individuals apparently occurs following spawning season. Continued survival of leopard darter populations is dependent upon these individuals, because of the small number of adults surviving a second year or older.
MeasurementsLength: 3.42 in (<8.7 cm)
The leopard darter is tan to olive in color, with a distinctive pattern of 11 to 14 round black spots along each side.
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