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<br />Colonel John N Reese
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<br />D R AFT
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<br />Arizona, New Mexico, Utah, and Colorado, as well as Federal representatives
<br />from the National Park Service, the Bureau, and the Service) recommended that
<br />the San Juan River be added to the Colorado squawfish recovery plan. The
<br />updated Colorado squawfish Recovery Plan (August 6, 1991) states that the
<br />species can be downlisted to threatened status when all recovery areas
<br />(including the San Juan River from lake Powell upstream to the confluence of
<br />the Animas River) have naturally self-sustaining populations. The San Juan
<br />River is also iAcluded in the delisting criteria.
<br />
<br />Razorbac~ Suc~er
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<br />Historical and Current Distribution
<br />
<br />The razorback sucker, an endemic species unique to the Colorado River Basin,
<br />was historically abundant and widely distributed within warmwater reaches
<br />throughout the Colorado River Basin. Historically, razorback suckers were
<br />found in the main stem Colorado River and major tributaries in Arizona,
<br />California, Colorado, Nevada, New Mexico, Utah, Wyoming, and in Mexico (Ellis
<br />1914; Minckley 1973). Bestgen (1990) reported that this species was once so
<br />numerous that it was commonly used as food by early settlers, and further,
<br />that commercially marketable quantities were caught in Arizona as. recently as
<br />1949. In the Upper Basin, razorback suckers were reported in the Green River
<br />to be very abundant near Green River, Utah, in the late 1800's (Jordan 1891).
<br />An account in Osmundson and Kaeding (1989) reported that residents living
<br />along the Colorado River near Clifton, Colorado, observed several thousand
<br />razorback suckers during spring runoff in the 1930's and early 1940's. In the
<br />San Juan River drainage, Platania and Young (1989) relayed historical accounts
<br />of razorback suckers ascending the Animas River to Durango, Colorado, around
<br />the turn of the century. Platania and Young (1989) also reported the 1976
<br />capture of two adult razorback suckers by VTN Consolidated, Inc., from an
<br />irrigation pond adjacent to the San Juan River near Bluff, Utah.
<br />
<br />In August 1990, the New Mexico Department of Game and Fish (lief Ahlm,
<br />Fisheries Specialist, pers. comm.) interviewed two anglers from Aztec, New
<br />Mexico, who claimed to have .commonly. caught razorback suckers in the Animas
<br />River near Cedar Hill bridge in the 1930's and 1940's. When the two men were
<br />shown a battery of photographs, including roundtail chub (Gila robusta),
<br />humpback chub (Gila ~), bony tail (Gila eleqans), bluehead sucker
<br />(Pantosteus discobolus), flannelmouth sucker (Catostomus latiDinis), razorback
<br />sucker, and Colorado squawfish, they both immediately identified the razorback
<br />sucker as the fish they had caught. However, prior to the 1976 capture by VTN
<br />Consolidated, Inc., there were no scientifically verified reports of razorback
<br />sucker captures in the San Juan River drainage.
<br />
<br />The current distribution and abundance of razorback sucker has been .
<br />significantly reduced throughout the Colorado River system (McAda 1987; McAda
<br />and Wydoski 1980; Holden and Stalnaker 1975; Minckley 1983; Marsh and Minckley
<br />1989; Tyus 1987). The only substantial population of razorback suckers
<br />remaining, made up entirely of old adults (McCarthy and Minckley 1987), is
<br />.found in lake Mohave; however, they do not appear to be successfully
<br />recruiting. While limited numbers of razorback sucker persist in other
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