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<br />The following biological opinion is based on information provided by the GCES including
<br />endangered fish annual research repom for Conservation Measure Five, information in the Draft
<br />EIS dated January 1994, a June 17, 1994, memorandum from Reclamation modifying the
<br />preferred alternative of the draft EIS(U ,S. Bureau of Reclamation 1994), data in our files, and
<br />other sources of information. Additionally, because final GCES technical and integration
<br />reports, or their summaries, were no,ta\(ailaWe to the Service,the benet!t of those analyses was
<br />not available for this biological opinion.
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<br />BIOLOGICAL OPINION
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<br />It is my biological opinion that the proposed .operation of Glen Canyon Dam according to
<br />operating and other criteria of the MLFF, as described in the Draft EIS and further modified
<br />by Reclamation's June 17, 1994, memorandum, is likely to jeopardize the continued existence
<br />of the humpback chub and razorback sucker and is likely to destroy or adversely modify
<br />designated critical habitat. It is my biological opinion tbat the proposed operation of Glen
<br />Canyon Dam according to operating and othe.r criteria of the_MLFF, as described in tl}e Draft
<br />EIS and June 17 memorandum, is not likely to jeopardize the continued existence of tJ:le bald
<br />eagle, Kanab ambersnail, or peregrine falcon. This biologicaJ. opinion supports mainten3.l1ce of
<br />biological diversity associated with the Jiistoric hydrog~ph and the dependent ecQsystem
<br />components including other native fishes.
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<br />DESCRIPTION OF PROJECT
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<br />BACKGROUND
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<br />Glen Canyon Dam was completed in 1963 as a feature of the Colorado River Storage Project
<br />(CRSP). At Reclamation's request, a biological opinion was prepared on May 25, 1978, on the
<br />effects of the dam on the Colorado River. That opinion found that past, present, and future
<br />operations of the dam jeopardized the continued existence of the humpback chub and limited
<br />recovery of the humpback chub and Colorado squawfish (Ptychocheilus lucius). The Service
<br />recommended studies to determine the potential impact of warming the release water, the
<br />ecological needs of the species, methods to reduce known constrainfng factors of low
<br />temperature and frequent fluctuations, and relationship between mainstem and tributaries and
<br />utilization by species. Jeopardy was not included for the Colorado squawfish since it was
<br />considered extirpated from Grand Canyon in 1978, and it remains in that status today. The
<br />bony tail chub (Gila elegans) and razorback sucker were not listed in 1978 and, therefore, were
<br />not included in the opinion. The bony tail chub, a species closely related to the humpback chub,
<br />was listed as endangered in 1980, but is considered extirpated from the Grand Canyon. The
<br />razorback sucker was listed as an endangered species in 1991.
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<br />A late 1970's program to increase peaking power at Glen Canyon Dam was terminated in 1980,
<br />but uprating and rewinding of the hydroelectric generators was determined to be feasible by
<br />Reclamation. The Service on April 2, 1982, while concurring with Reclamation's biological
<br />assessment that the incremental increase in uprated operations did not further increase jeopardy,
<br />restated that the 1978 jeopardy opinion was still in effect.
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<br />15 December 1994 final biological opinion 2-21-93-F-167
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