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4t <br />I., <br />INTRODUCTION <br />The Colorado River is home to some of the most unique fresh water fishes in <br />the world. Four of these native "big river fishes" are now dangerously close <br />to extinction -- the Colorado squawfish, the humpback and bonytail ct}ubs, and <br />the razorback sucker. Historically, these four fishes were found in abundance <br />throughout the Colorado River and its major tributaries, which are legally <br />divided into Upper and Lower Basins at Lee Ferry on the Colorado River <br />mainstem just below Glen Canyon Dam. <br />Currently, the Colorado squawfish has been extirpated from the Lower Basin, <br />except for any remnants of re-introduced, experimental populations, but <br />natural populations still persist in the Upper Basin. The squawfish <br />populations in the Yampa and Green Rivers of the Upper Basin have been greatly <br />reduced but may be fairly stable. The bonytail is the rarest, with very few <br />captures in the wild in the last decade. The humpback chub, which was not <br />described as a separate species until 1946, may be most numerous in the Lower <br />Basin, in and near the confluence of the Colorado and Little Colorado Rivers <br />in the Grand Canyon. Humpback populations persist in the Upper Basin in the <br />Yampa, Desolation, Gray, Cataract, Black Rocks, and Westwater Canyons. The <br />razorback sucker was once widely distributed, but today its populations are <br />mostly older fish, concentrated in the mainstem reservoirs on the lower <br />Colorado River, most notably Lake Mohave, and in the lower Yampa and Green <br />Rivers of the Upper Basin. Five other native fishes might be included with <br />these four in a community that inhabits the deeper and warmer habitats of the <br />Colorado River system -- the roundtail chub, the fannelmouth sucker, the <br />bluehead sucker, the woundfin, and the speckled dace. Each of these big river <br />fishes is also in serious decline. <br />Two major reasons are cited for the decline of these fishes. First, dam <br />construction over the past century has fragmented their habitat and has <br />reduced or altered flows for significant reaches of river, which has disrupted <br />their natural life cycles. See Figure 1. Second, the introduction of a wide <br />variety of non-native fishes into the system and their proliferation in <br />reservoirs and warm water habitats is also thought to be a very significant <br />factor in the decline of the native, big river fishes. The introduced non- <br />natives both compete with and prey on the native fishes. <br />This paper will first review the principal features of the Endangered Species <br />Act (ESA) which have been applied to the squawfish, razorback, and the two <br />chubs. Many of these features are currently being scrutinized by Congress and <br />could be amended in the near future. This paper will then examine the two <br />programs that have been developed in the Upper Colorado River Basin, and the <br />one that is emerging in the Lower Basin, for implementing the recovery of the <br />Colorado River fishes that have been listed under the ESA and for complying <br />with the regulatory features of the ESA. These programs are organized around <br />the regional jurisdictions of the most responsible federal agencies -- the <br />Upper Basin Program falls within the purview of Region 6 of the U.S. Fish and <br />Wildlife Service (FWS) and the Upper Colorado Region of the U.S. Bureau of <br />Reclamation (BOR); the San Juan Program is the concern of Region 2 and 6 of <br />the FWS and the Upper Colorado Region of the BOR; and the Lower Basin is <br />mostly within Region 2 of the FWS and the Lower Colorado Region of the BOR. <br />This paper addresses the relatively recent development and policies of these <br />recovery implementation programs and is not a complete history. <br />This paper's main concern is that the recovery of the listed fishes may be <br />frustrated by the split in the regional jurisdictions of the most responsible <br />federal agencies, by the inattention to the recovery goals set for the full <br />geographic range of these fishes, or the absence of such goals in the case of <br />the razorback, and by a consequent but not always apparent divergence of <br />opinion as to how recovery should be defined. This paper's most important <br />conclusion is that the range-wide recovery planning and goal setting for these <br />1