Oiii l.ivini; Ri'soiiives — Fishes 



143 



Basis of the American Fisheries 

 Society Listings 



The 1979 and 1989 AFS listings were based 

 entirely on biological considerations throughout 

 the geographic range of the taxon and ignored 

 jurisdictional or political considerations. For 

 example, the johnny darter (Etheostoina 

 iiii^niiu) IS a small darter found in clear streams 

 from the East coast to the Continental Divide; 

 the species reaches the western periphery of its 

 range in Colorado. Johnny darters are rare in 

 Colorado, which recognizes the species" rarity 

 (Johnson 1987). Throughout most of its range, 

 however, the johnny darter is common and thus 

 was not included in the AFS listing. Only those 

 taxa that appear imperiled are included in the 

 lists; populations were not considered unless 

 they were distinct enough to he recognized as 

 subspecies. 



The preliminary 1979 AFS listing was 

 obtained by asking knowledgeable fishery sci- 

 entists which fishes should be included. Those 

 taxa were added to a 1972 listing of protected 

 fishes (Miller 1972) that was then sent out to 

 every state and to selected federal agencies for 

 review. 



The native fish faunas of some areas of the 

 country are better studied than others and may 

 therefore be better represented in the listing. 

 The 1989 listing used knowledgeable biologists 

 but not extensive agency review to build upon 

 the 1979 listing. These two data bases provide 

 the best information presently available on rare 

 native fishes of the United Stales. 



Changes in the Status of Native 

 Freshwater Fishes, 1979-89 



Analysis of the 1989 list provides some 

 basic information on the status and trends of the 

 native fishes of the United States. About one- 

 fourth of our native freshwater fishes are per- 

 ceived to be imperiled. Ninety-three percent of 

 imperiled species are in trouble because of the 

 deteriorating quality of the aquatic habitats on 

 which they depend; this deterioration results 

 from physical, chemical, and biological effects 

 to our surface waters and underground aquifers. 

 Overuse, introduction of non-native species, 

 disease, and other problems that also affect our 

 native fishes cause much less endangerment 

 than habitat destruction. 



The increase of taxa of fishes between the 

 1979 (189 taxa) and 1989 (234 taxa) AFS list- 

 ings does not include 19 taxa that were removed 

 from the 1989 listing because of extinction, tax- 

 onomic revisions, or better information on sta- 

 tus. Seventy-five imperiled taxa that did not 

 appear in the 1979 AFS listing were added to 



Table. Population trends lor 

 endangered, threatened, and spe- 

 cial concern freshwater fishes of 

 the United States whose status 

 changed between 1979 and 1989 

 (Wiiriamsetal. 1989). 



the 1989 AFS listing, an increase of 38% in a 

 single decade. In addition, the status of 39 fish- 

 es was changed: 7 taxa improved (e.g.. changed 

 from threatened to special concern), 22 taxa 

 declined, and 10 taxa were recognized as 

 extinct (Table). No fish was removed from the 

 1989 AFS listing because of successful recov- 

 ery efforts, indicating that our freshwater fishes 

 continue to decline overall, and factors causing 

 those changes appear diftlcult to reverse. 



The relation between declining aquatic habi- 

 tats and fishes facing extinction is not as simple 

 as might be expected. Species with limited dis- 

 tributions are more likely to be jeopardized by 

 changes in their local aquatic habitats than are 

 species with extensive ranges. Many fishes on 

 the lists have local distributions, and a few, such 

 as the Clear Creek gambusia {Gambusia hete- 

 rocliir) and Devils Hole pupfish {Cyprinodon 

 diaholis). are limited to a single spring. These 

 unique fishes could be lost by a single, isolated 

 event. Some of the widespread species included 

 in the listings — such as paddlefish (Polyodon 

 spatlmla) and six taxa of sturgeons — depend on 

 large rivers, and their inclusion indicates wide- 

 spread threats to these extensive habitats. 



States with the most listed (imperiled) 

 species include California (42), Tennessee (40), 

 and Nevada (39). Somewhat fewer listed fishes 

 are found in Alabama (30). Oregon (25). Texas 

 (23). Arizona (22). Virginia (21). North 



