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<br />13378
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<br />Federal Register f VoL 59, No. 54 f Monday, March 21, 1994 / Rules and Regulations
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<br />inciirec!ly conbibuting to recovery of a
<br />species. .
<br />Areas outside of critical habitat are
<br />still subject to lOeCtion 7 consultation. on
<br />whether or nol1ln ai:tionis likely to
<br />jeopardize the continued existence of a
<br />species, and section 9 "take"
<br />prohibitions for an action !hat may
<br />affect Golorad<> River endangered fishes
<br />or their habitat. The Service anticipates
<br />that the importance of areas outside of
<br />critical hahila1 to the conservation of the
<br />Colorado Riv..r.'';''n.ng~red fishes will
<br />be addressed through section 7, section
<br />9. ana sectimi 10 pemUt processes, the
<br />recovery plaiming'process. and other
<br />appropriaie Slate and Federal laws.
<br />Primary C<msli!tlenf Elements
<br />In detennining Which areas.to
<br />designate as aitiCal habitat for a
<br />species, the Service considers those .
<br />physical and bioI.ogical aUrlbutes that
<br />are essential toJlpecies conservation
<br />(i.e., constitusl!telaments). Such
<br />physical and bin'ng;r.ol features are
<br />stated in 50 CFR424-12 and incInde.
<br />but are noi limited U>. the following
<br />items: (ll splicefoi iDdividua181ld
<br />poP'ili.'tion grow:1ILand for JIOl2II8l
<br />behaVIor; '..,:"., ._ .. . .
<br />(2) Food. Wa!iIr..:air.li8h1. minerals. or
<br />other nulriliOl1al or physiological
<br />'requiremeiilli;',.. .'
<br />. (3) Cover<iiSiililtilr;
<br />(4) Sites for~g, reproduction.
<br />reariDg of offijillii.g; germination, or
<br />seed dispersal; Bi1d generally;
<br />(5) Habitats that are protected from
<br />disturbancaor are representative of the
<br />historical geogmphical and eoological
<br />distributionsofa species,
<br />In addition,1h9 Act stipulates that the
<br />ereas conl$ling these elements may
<br />require special m8ua.oc;.uJ.t~ut
<br />considemtions.mprotection,
<br />Detailed a-:..i}lli=. and the.
<br />biological basis for the constituent
<br />elements ..... presented in the Draft
<br />Biological S"ppmt'Document {Marl1lux
<br />et al. 1993), lD.1:OIlsidering the
<br />biological basis for 1letermining critical
<br />habitat, the SIlnice focused on the
<br />. primary physicsland biological
<br />elements essenliallo the conservation of
<br />the species.-1:he primary constituent
<br />elements llRl interrelated in the Ufe
<br />history of these species. This
<br />relationship was a prime consideration
<br />in the designation of critical habitat.
<br />The Service is required to list the
<br />known primaIy constituent elements
<br />together with a description of any
<br />critical habitat that is designated.
<br />The primmy conslitaent elements
<br />determined lIecessary for survival and
<br />recovery of the four Colorado River
<br />endangered :fishes include, but arellot
<br />limited to:
<br />
<br />Water
<br />
<br />This includes a quaiility of water of
<br />. sufficient quality Ii.e~ temperature,
<br />dissolved axygen.lackofcnnf.minants,
<br />nutrients. turbidity, etc.} that is
<br />delivered to a specific location in
<br />accordance with a hydrologic regime
<br />that is required for the particular life
<br />stege for each species.
<br />
<br />Phyoical Habitat
<br />
<br />This includes areas of the Colorado
<br />River system that are inhabited or
<br />potentially habiteble by fish for use in
<br />spewning. nursery, feeding, and I88IiDg.
<br />or corridors between these areas. In
<br />eddition to river cl1annels, these areas
<br />also include bottom lands, ski. .
<br />channels, secondary channels. oxbows,
<br />backwaters, and other areas in the 100-
<br />yeer flood 'plain, which when inundated
<br />provide spawning, nursery, feeding and
<br />rearing habitats, or access to these
<br />habitats,
<br />
<br />BioJosi<:al EaviromDllIIt
<br />
<br />Food supply, predation, and
<br />competitIDnare i:lnportant elements of
<br />the biological environment and are
<br />considered components ofthls .
<br />con.stilumt ~lement. Food supply is a
<br />. function ohmment supplv,
<br />productivitY,1lJld aval1abiiityto each
<br />life stege ofthefipecies. Predation and
<br />competition, although considered
<br />nol2ll8l compooen1sof this
<br />environment, are out of balance due to
<br />introduced nonnative fish species in
<br />many areas. .
<br />
<br />Additional Selection Criterioforthe
<br />Razorback Sucker
<br />
<br />BecaUse it recovoryplan for the
<br />razorback sucker has not been
<br />completed. edditional selection criteria
<br />were developed to assist the Service in
<br />making a determination .of areas to
<br />propose as critical habitat. Previous
<br />Service findings, published and
<br />unpublished literature SOUl'Ces, and
<br />discussions with individual members of
<br />the Colorado River Fishes Recovery
<br />Team were utilized to develop the
<br />constituent elements and additional
<br />selection criteria.
<br />Adult razorbill:k suckers have
<br />displayed a degree of versatility in their
<br />ability to survive and spawn in different
<br />habitats. However, razorback sucker
<br />. populations continue to decline and are
<br />considered below the survival level.
<br />TIms, as versatile as theadult'1ife stage
<br />of T8zorback sucker appears to be in
<br />selecting spawning habitat, there has
<br />been little ornorecruitment of young to
<br />the adult population. Therefore, special
<br />consideration was given to habitats
<br />required for :reproduction and
<br />recruitinent.
<br />
<br />The following seloction .
<br />consi1ierations were used by the SeIVi<:e
<br />to help determine areas necessmy for
<br />survival and recovery of the 'lUu",.ck
<br />suder, .
<br />1. Presence of known or suspected
<br />wild spewning popuJali<ms, although
<br />recruitment may be limited or
<br />nonexistent.
<br />2. Areas where juvenile reroriJack
<br />Slickers have been collected or which
<br />could provide suitable nurnery habitat
<br />(backwaters, flooded bottom lands, m-
<br />coves l.
<br />3. Areas presently occupied o<lhat
<br />were historicaliy occupied that are
<br />considered necessary for recovery aiId
<br />that have the potential. for ,
<br />reestablishment ofrazoiback suckers.
<br />4, Areas and .....ter required to
<br />maintain rangewide fisb. dim1'bntion
<br />and diversity under a variety of
<br />physical, chemicaL and biological
<br />conditions.
<br />5. Areas that need special
<br />management.,. protecIi<ll1 to insure
<br />razorback survival and '-"CO .6". 1'hese
<br />areas once met llre habitat needs of the.
<br />razorback sueker and may be
<br />recoverableWith additional ~
<br />and managelDllUL . .c. "" .
<br />The primary <:onstituent iHemenls . ,
<br />were identilied thmnghout the '..
<br />historical range of the Colorado River
<br />endangered fishes. In additiOD, the five
<br />selection considerations described
<br />above also were used to evaluate
<br />potential razorback sucker critical.
<br />habitat areas. Thecritical habitat
<br />designations were based "" the prima:rjo
<br />constituent elements, published and
<br />unpublished somces ofiirl'ormation,
<br />Service reports and other findings,
<br />recovery plans tfor Colorado squawfish,
<br />humpback chub, and bonytail chub), the
<br />additional selection considerations, and
<br />the Service's preliminary recovery goals
<br />for the razorback $Ucker,
<br />
<br />.A.rfj:ustments 1o.8fplYV'1nrlpc
<br />
<br />The l00-year flood plain iSlleneral1y
<br />included es part oflhe critical habitst
<br />designation: however. only those
<br />portions of the floOd plain that contain
<br />the constituent elements are considered
<br />part of critix:al habitat. Specific areas in
<br />the flood plain must be evaluated on a
<br />case.by.case basis to deterritine if the
<br />areas constitute critical habitat. The
<br />Service stresses that, although critical.
<br />habitat may only be seasonally occupied
<br />by the fish. such habitat remains
<br />important for their conservation.
<br />Protection of such seasonally occupied
<br />habitats contributes to the conservation
<br />of the species. .
<br />As a resuh of obtainiDg additional
<br />biological information and review of
<br />comments received during the public
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