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<br />habit. Some sprln~ll~ht"~ In rht" \,\'hm- Rn'er live at
<br />temperaturcs t'xu:edlllF: 16.~ c. ,!OJ at eX[fl.mely
<br />low oxy~en (OOCt"n[f.Hlons. l\tnsr pnruL.luons an:
<br />threAteneu b~ IntruJu(eu fisht.s. hut thnsr- In'lng In
<br />hot, lo......oxygcn ....ater havt" It'S5 or ;1 prohlem SjOlt.
<br />the exotlc Spt'Clt.S cannut In\J,tk tht"lr spcCI.d habH;It.
<br />The ~lonkey Sprm.~ puptlsh (FI}::, -7) of s\luthern
<br />Arizona was nor so luck\' LIf~em'lUlh r..ISS w<:re
<br />Imrouu(eu Into tht'lr hablt,\t. ~nu WIt!1I0 J fev.
<br />mtlnths, the n,HJn' spt'C1es W,IS F:onc.
<br />
<br />
<br />< ~
<br />:iI ,;:.~
<br />
<br />Figure 77, E:w:hnCI fishes from the Monkey Spnng system,
<br />Arizona. Above Monkey Spring pupllsh, 55 mm, Below: Gila
<br />chub, 15 em.
<br />
<br />--
<br />
<br />
<br />DISCUSSION AND CONCLUSIONS
<br />
<br />or .11 stncd\" frt"shw,lter fishes dlScusseu h<:rt". ll)
<br />tl((ur only 10 ~leXIC\l, 9 .HI: ('n]~. 10 [hr- Crlltt'd
<br />St,J[t's. and 22 spent's .lft" s!urnI hr the tWO
<br />('Ollntnes, tht' J..q ,en.lnF t(l dJusuJte [hl. re/Z.Hmal
<br />naturt. "f tht.' {auna Thlhe: ftlund ani\' m (1ne: \It tht.
<br />llthet Country rt'prl"St"nt In IJrl"t" p.lft 10CJ.l endemICS.
<br />whl(h demons[fJ.[e m rhe:lr Iso!.Hllln some (It' the
<br />uniqueness of (isht's m .If!.l 1.!Ods In 19S9. 2:-;
<br />\6Slfr) (1f the -4! tJ.xa were olliudlly rt'cl.)l"nlzt",l
<br />(ht're.lt"tt'r bstedl .IS thrent'm.J. end.'ngt'r,'J. or ot"
<br />spe:Clal cuncern by the Amc:ri~',ln Flsht"flt", '~)Clety
<br />Three speCIes from tht. replln ILlS \'el".ls Spt'ckled
<br />JAce. Pahranal",H splneda(e, anJ ~fonkt'y Spnn,e
<br />
<br />rup!lsh, not InduJt.J In the abtl\"l' wmpllatlOn) were
<br />rr-porred to han' slIfft"rtu r-xtlnuion.
<br />Ddinltl\Jn of Just hllw much trouble thest' fIshes
<br />art" ..Ictu.llly t"ncOllntt"rlrlt" IS ,I maJIH prohlem. FIShe:s
<br />.Ire ullricult ro .Is~ess fwm tilt. standpOint of
<br />populafJOn sums. In (an. the,' .1ft. t'\.en often
<br />dlffi(ult w diSCUSS ~Im'e thr-y 11\.e in w;uer. ,I
<br />mt"dium 1n(\lO\"eOlt"nt for humalls to r-nter. FIshes are
<br />furthermore difficult hl llhser\'c' or capturt". and even
<br />to Identify alter the\" ,Ire: In h.lnd. L;lsrly. for SOffit'
<br />rl',ISlJn the:y are oftr-n considered "seconu.c1ass
<br />cHlzt'ns" whr-n cllmpared with four.k~td. furry ur
<br />fr-,ltbt'rl.J nt"M.ts. humans Idt.ntd). morr- with warm.
<br />blol,ded JOlmals [hat rt'scmble tht"mseln's.
<br />Dt'SPlft. [his. if ,me Jt"termlm's thaI a tlsh t'XI~tS
<br />only as a hundred or so 1/1diviuuals In a sio~lt: tiny
<br />sl'rlO~, J[ can re..ludy be udined as c'nJ.ln~ert:u since
<br /><l sln.c:k e\"t'm (Iluld uestroy It, \'\'idesprt'..Id spt'cies
<br />Ht" ,111Othn m,lnt.r, and ffillSf Ilshes In tillS ref!:ion
<br />....Tre, In fan, retltlvdy wide r.lnt"In~. A fish may
<br />becomt' t"rl'atly reduceu in rJn,gt., such ..IS the
<br />S\lOUrJn rl1pmlOnow thJ.f ltn-J from Western New
<br />.\lr-xico to tht' Color.h~il Rln'r tht"n SOuth thtou~h
<br />At1zonJ ,IOJ SonorJ. It now \)LCUl'lt'S ft'wer than 10
<br />n>l[uLd IOGlhtles In rhe L:mred States OntO mi~ht
<br />..I]SO believe thiS suffiuem to defim- t"nJ.\ngermem.
<br />Howl"'l"Cr. ea(h eXIsting porllbtlon cunSlSts o(
<br />hundreds or tholls,lnds of IndiViduals, .Ind Llverall
<br />pllpulatllln SIZt" mJ]" Mtu::i1ly number 10 [he millions.
<br />TillS h ..I subsf,intlal number whr-n compared with
<br />SOfTlt' enJ.In~nc'J fl'rresttlal species such as
<br />Clhfurnl<l Condor \lr .\texi(an \Volf. .....hich drt"
<br />rt.duct"ll tll only .1 It-..... IOdl\'JJuals. Hllwevt'r, a shorr.
<br />ltn.J spt'cics such as WpmlllOI)W mJY dlsaprear in a
<br />yeM or less when slIhlent'd [U an effiuem prt.dMor
<br />such as [he IOrroduu:d mllsqlllwllSh. so size uf lucal
<br />P,)('uIatlOns ma~' hJ\T little [0 do with its ,lcm.II
<br />status.
<br />Others, such ,is btloyrad 01 the Colur,ldo River
<br />m,lln"fre,\m, m,iY bl' cqu,i1ly ,IS rare as CahforOlJ.
<br />ConJ'H Fewer than <;0 IOdl\'Jduals have been cJ.u~ht
<br />JespHl' IOH'nSI\'r- efforts 510((' I t)-S ThIS fIsh IS SI;
<br />rare th,1l I( ClIlnOf h\. studIed In n.\ture. Further. it
<br />,lppC.HS to be hybrlJizlO~ with otlu'r chubs because
<br />rht' fr-w rr-malfiln,i.: wliJ Indl\h.lud]S "Inn~lt flnu
<br />sUf[Jt.le rnatt:~, BII)II\i.:,IStS ba..-e no firm iue;lS wh~.
<br />[hiS Srt:ClC~ h,ls Jis,lppe3reu A, with both the
<br />nmdllr and wI,It. aftltl(lJl Ptllrat:JlIlln has been
<br />lfiltlJteJ to pt'rpetllJte the b,)nyt.lll. ,11[hou,ch it has
<br />r.n.n dlt"tic-ult [{l (Jptllrt. r-oou/Z.h IOdl\lduals to
<br />est.lbh~h .1 "-1.Ir.le r.rlwdsroc:k.
<br />An IOft"rml.'"dIJte stJ[e bt.rwcen the WpmlOnov.
<br />('xamplt: ,Ind th,H of bnnytJd 1001:lI..-es thc razllrr.ack
<br />su\-ker. which enJo~.s Ont: populatwn th.u excecds
<br />')0.000 lOJI\'luu;ds III LJke ~{,\h,i\'c ArtzonJ.'
<br />;\c\".ld,l. yt:t IS ,llmost ,':\)[Je tt()m the rem.llOun \If Its
<br />
<br />39
<br />
<br />01112
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