Comment on FR Doc # 2012-17950

The only extant population of the Diamond Darter, Crystallaria cincotta, lives in a stretch of the Elk River in WV. Populations that occurred in Green, Muskingum, and Cumberland rivers are almost certainly gone. These rivers have been well sampled in recent decades by experienced ichthyologists using a variety of techniques. Based on my experience with scientific investigations of darters, including authorship of over 50 peer-reviewed publications, the "Handbook of Darters," (1983), and "Peterson Field Guide to Freshwater Fishes of North America (2011, 2nd edition)," I am convinced that the Diamond Darter is endangered. With only one extant population in the Elk River drainage that is subject to potential modifications, including coal mining, impoundment, pollution and timber harvesting, the loss of all remaining individuals of the species is clearly possible. The reach of the Elk River chosen for protection as critical habitat includes the only population of the species. The other area selected for critical habitat is the Green River in the historical range of the species. With at least 150 species of fishes and 70 species of freshwater mussels recorded from this stretch of river, it is more likely than any other to offer the potential for re-establishment of a second population. Green River is the focus of conservation efforts because of its high biological diversity and is a logical choice as a refuge for the Diamond Darter. The Diamond Darter is one of two species in Crystallaria. The other species, the Crystal Darter, C. asprella, also has been extirpated from much of its historical range. The two species are morphologically and ecologically among the most unusual species in Percidae, one of the most diverse groups of North American freshwater fishes with 201 native species. Protection provided by designating critical habitat will protect other components of our native freshwater diversity without negative environmental impacts on other species.