Our Living Resources — Fishes 



145 



each region (Hocutt and Wiley 1986): (a) 

 Atlantic Slope — coastal waters I'rom the 

 Roanoke River (Virginia) southward to the 

 Altamaha River (Georgia); (b) Peninsular — 

 waters from the Satilla River (Georgia) to the 

 Ochlockonee River (Florida); (c) Lower 

 Apalachicola Basin — waters from the 

 Apalachicola River (Florida) westward to the 

 Perdido River (Alabama); (d) Lower Mobile 

 Basin — lowland portions of the Tombigbee and 

 Alabama rivers and tributaries (Alabama and 

 Mississippi); (e) Lower Mississippi — the 

 Mississippi River and its eastern tributaries 

 below the Ohio River (Mississippi, Tennessee, 

 and Kentucky); (f) Interior Plateau — upland 

 waters of the middle and lower Ohio River and 

 southern tributaries, including the lower 

 Cumberland and Tennessee rivers (Kentucky 

 and Tennessee); and (g) Southern Appalachians 

 — upland waters of the mountains in the geo- 

 logical provinces known as the Cumberland 

 Plateau, Valley and Ridge, Blue Ridge, and 

 Piedmont, south of the Kanawha (West 

 Virginia) and Roanoke rivers. Many tlshes are 

 widely distributed in the Southeast and occur in 

 two or more hydrologic regions. 



Imperiled Freshwater Fishes 



The Southeast has about 485 known species 

 of native freshwater fishes, representing 27 

 families. Most of the diversity of the southeast- 

 em fish fauna is in five families: the darters and 

 perches (family Percidae; 31.3%); the minnows 

 (family Cyprinidae; 29.7%); the madtoms and 

 bullhead catfishes (family Ictaluridae; 6.8%); 

 the suckers (family Catostomidae; 6.6%); and 

 the sunfishes and basses (family Centrarchidae; 

 5.8%). The greatest diversity is in the 

 Appalachian Mountains and Interior Plateau 

 (Fig. I ), but other regions of the Southeast also 

 harbor many more species than do similar-sized 

 geographic areas elsewhere in the United 

 States. 



As of January 1994 the U.S. Fish and 

 Wildlife Service (USFWS) had designated 15 

 southeastern fish species as endangered and 12 

 as threatened, representing 6% of the entire 

 regional fish fauna. Ninety-three fish taxa 

 ( 19%) are imperiled (endangered, threatened, or 

 of special concern) in the Southeast, including 

 proposed listings and those recognized by other 

 authors (Williams et al. 1989). During the past 

 25 years, only seven species were upgraded by 

 the USFWS, mainly because of discovery of 

 new populations, inadequate knowledge at the 

 time of listing, or invalid taxonomy. No endan- 

 gered or threatened species have been delisted. 

 A steady upward trend in designation of imper- 

 iled southeastern fishes has occuned in the last 

 20 years (Fig. 2); the number of species con- 



sidered imperiled by the USFWS increased 

 from 3 (less than 1%) in 1974 to 84 (17%) in 

 1994 (USFWS listings only). During the 10- 

 year period from 1979 to 1989, the number of 

 species considered imperiled by the American 

 Fisheries Society increased from 63 ( 13%) to 81 

 (17%; Fig. 2). 



An alarming 21% of the nearly 300 species 

 of minnows and darters are imperiled in the 

 Southeast. Considered alone, more than 30% of 

 the 150 species of darters are in trouble, repre- 

 senting the highest total number of species in 

 any one family. Madtom catfishes (genus 

 Nolitrits) are also disproportionally imperiled 

 among large families of more than 30 species 

 (Etnier and Stames 1991; Wanen and Burr 

 1994). Among smaller groups of fishes, the 

 most severe status is among the sturgeons and 

 paddlefish. where seven of the eight (86%) 

 southeastern species are in jeopardy. In terms of 

 ecological requirements, most imperiled species 

 are those that live in small to large creeks and 

 small rivers, are closely associated with clean 

 stream-bottom substrates, or are isolated in 

 spring and cave environments. 



On a regional scale, the greatest number of 

 imperiled species occurs in the highland areas 

 of the Appalachians and Interior Plateau, 



100 



Fig. 1. Total numbers of freshwa- 

 ter fishes and percentage imper- 

 iled by hydrographic region of the 

 southeastern United States. 



Fig. 2. Total numbers of imperiled 

 fishes in the Southeast during the 

 last 20 years, as recognized by the 

 American Fisheries Society (AFS) 

 and the U.S. Fish and Wildlife 

 Service (USFWS). Numbers repre- 

 sent imperiled species during years 

 of listing activity. 



