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Frecklebelly darter
The frecklebelly darter (''Percina stictogaster'') primarily occurs in the upper Kentucky and Green river systems of eastern and central Kentucky and north-central Tennessee, being found mostly in the Cumberland Plateau and Highland Rim regions.〔Warren Jr, Melvin L., et al. "Diversity, distribution, and conservation status of the native freshwater fishes of the southern United States." Fisheries 25.10 (2000): 7-31.〕 The fish gets its name from gets its name from the scattered dark spots on its relatively pale underside. However, a possible more telling characteristic of the species is the systematical arrangement of the spots at the base of the tail as well as the continuous stripes down either side of the back. Total population size is unknown but figured to be relatively large. The frecklebelly darter is a benthic darter that relies on invertebrates as its principal diet. The frecklebelly darter can be found primarily in creeks and small rivers with a moderate gradient and a pool/riffle type flow, and spends most of its time in midwater areas of the stream.〔Strange, Rex Meade, and Brooks M. Burr. "Intraspecific phylogeography of North American highland fishes: a test of the Pleistocene vicariance hypothesis." Evolution (1997):885-897.〕 The major threats of the frecklebelly darter include decimation through perturbations such as strip mining as well as stream channelization projects. The darter is thought to have a high resilience with minimum population doubling time less than 15 months; it is also believed to have low vulnerability. Frecklebelly darter females contain about 100-300 mature ova depending on size. Fish become mature by age 1. Spawning in this darter species involves egg burial where the male mounts the female and deposits eggs in deep depressions created by receptive females.
==Geographic distribution==
The frecklebelly darter has a rather small distribution. Found in only two states, Tennessee and Kentucky, the species is endemic to higher elevation streams and reservoirs. found primarily in the Upper Kentucky and upper Green (including Barren River) river systems in eastern and central Kentucky and north-central Tennessee. The darter propagates upland streams of the Cumberland Plateau and central portions of the Highland Rim. Fairly common in Kentucky River drainage (where occurs from Red River upstream and including the South Fork), the darter is uncommon and localized in the Green River drainage. In the Green River, the frecklebelly darter occurs primarily upstream of the confluence of the Little Barren and Green rivers. In the Barren River, it is most common upstream of the confluence of Drakes Creek and the Barren River. The frecklebelly darter is restricted to large tributaries in Tennessee, primarily of the Barren River system in Clay, Macon, and Sumner counties. There is an old record from the Nolin River system, where the species no longer occurs.〔 The frecklebelly darter as well as most other darter species in the area are vulnerable to decimation through perturbations such as strip mining; stream channelization projects threaten available habitat in Tennessee. It is believed that these factors as well as the damming of natural river systems may have extirpated the species from other areas in the southeast. Non-native Invasive fish species could also be a cause of limited distribution.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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