<br />
<br />-204'-~
<br />
<br />. . . - CALIFORNIAFI8H-A~"D- eA!-fE~-=:'_~'--n"
<br />
<br />-. In. a study such as this it has not been possible to collect or anah-Zl'
<br />enoug-h data to justify detailed conclusions as to the general econom; of
<br />the Colorado River and tbe many processp-s invol\"t~d in the prr,'lnction
<br />and utilization of food by its aquatic population. The Colnr,hto na..
<br />always been a changeable rivpr, and is still in a process of chan),Ze, FI~
<br />__'__~ droughts, ~h~fts in the ch~nnel, pl,ant su~cession-~ll ~ave played impC)f.
<br />--,,--:::-'tantTOles 1ll.lU eonfigurahon-and,ltshabltatsfor '\\:lldlIf~, The new da~
<br />have further altered such basic physical factors as flow, clarity, ternpt'n,
<br />ture, and even water chemistry. The introduction of exotic species. both
<br />vertebrates and invertebrates, has brought further changes j in fact. th~
<br />last few years have witnessed what may be a major biological revolution.
<br />With but incomplete factual data and with the realization that th~
<br />river and its fauna are still in a state of flux, it is none the less possible to
<br />make certain general statements. Inadvertently, man has improwJ mIlS!
<br />of the physical conditions for game fishes on the Colorado; and fortunately
<br />he had already introduced some fishes (bass, catfish) which, w1Jile tb~
<br />mayhave caused the decline of the native species, we~e well fitted to tail
<br />advantage of these physical changes and to create a sport fisherv "hm
<br />nonehad ej:isted before. ' .
<br />'He has also created some new hazards. He has introduced SpecifS
<br />(the carp, for example) wbich may have been detrimental to his QIlJJ
<br />interests. He has constructed diversions which cause some fish loss. H,
<br />has built roads and boat landings; has created resorts; has held" priv
<br />fish contests," advertised the sport on the river, and otherwise in crea,...,j
<br />the exploitation of its fishery. It must be admitted however that thest
<br />are all legitimate enterprises, and that up to a certain point he eaptur't
<br />of fish is not onlv not destructive to the fisherv but actually be!1eficia!
<br />When we sp;ak in terms of "beneficial" or t, detrimental:' w,~ u5ualb
<br />think only of those changes which seem to affect us personally, Thercf,)!'"
<br />it must be agreed that the "new Colorado" has been benefited b\' :~.
<br />changes and that the sum total of these changes far outweighs sUl.h ]",;."-"!
<br />as have occurred and may continue to occur. It seems certain that +
<br />entire biological production of the river (whatever its components 1I;'\'
<br />be) has increased tremendously.
<br />A biologist must regret that a limited but interesting natura! a5St'~.
<br />blage of species has had so many additions that its original !Jatme t~
<br />been destroyed, He must also regret that some species appear to bt' wr:
<br />ing on extinction, at least in the lower riyer. But he must also "11mit.tt~\
<br />the rise of the new population of exotic fishes has brought r('crealJl'i~:
<br />and utilitarian values which exceed those of distant davs. The yaIue '.~
<br />some sport fisheries of California and Arizona (trout, for exarnpk;, 0;:-'
<br />be measured mainly in terms of the pleasure and relaxation they br:n:::"-
<br />the angler; or it can be reckoned, to the merchant, in terms of the bU5,n:
<br />createIT bv sales to the fishermen. In the vallevs of the Colorado the \"3.-
<br />of the ga~e fish as food is also an important on'e. There are man~' fa.Jlli>~
<br />wbose subsistence in part on fish ser...es to alleviate their condition,
<br />
<br />administrarors of the two Stat~s ~ es~b.lish a. marked de~ree of .::ontrr,;
<br />over the fishery and to change WeIr POhCIes qUIckly and WIth a minimu!!;
<br />of effort whenever it appears advisable.
<br />
<br />OONOLUSIONS
<br />
<br />
<br />
<br />'::;,;'..;, '. , OF THE LOWER. COLORADO RIVER.,=.2G5-=--=---.-.-
<br />
<br />'~tt..'lie sport fishery of th .
<br />-"all-"- th ' ',e 1'1ver appears to bein a he lth .
<br />",',",."t:r.o'.-..::~", 1 e suthccess of, angling varies from season t,o s:asQ'Jn
<br />L",t' "'" ..lonO' € stream. T rt . ' ' ,
<br />,'-.1~'-~ifi~-' .0 . r.oa ce am extent this a
<br />,~~Wl~ .varlatIons m flow and turb'd't hi h ,ppears
<br />.D.~sattempt ro h th. 1 1 Y weare a con.
<br />"'Lf" . amess erlver, and there is little that th'
<br />".alS c.onservation agen . d e
<br />",c-,.,u ,-, -, ," - Cles can 0 or say to tr I
<br />eneral;th 'd fi h ' .' con 0 such
<br />., .:(.~:c>'-, ereSl ent s ermen are well satisfied with the
<br />
<br />''ot'.!eit that we can or nef'd t . t' ' --
<br />.",.."f ',,';;"'hi, ,h', 'il" ." 0 ms Itute any elaborate form of
<br />_ ,!! c W1 Improve It Th dd"
<br />;i,l!eo'fishes t 1 d' , e a ltlon of new species, either
<br />,..." ,0 an a rea v complex a~ bl .
<br />~o~,.isit believed that the .fisherv 'uld~mb age IS not recom-
<br />,#8.':existing--game fishes;-- .co ,e e~e~ted ~y further
<br />i:innumbers of some spec~ ~fO'~~~r hafn~ It IS beh~vedthar~--::-
<br />'some extent if the an " e 0 :alue. This can be '
<br />,fisb.eswhic,h,h 1 glelr.:vill turn hIS a.ttention towards
<br />", ,". ,'"",. e now arge ~ Ignores It'
<br />uttfeit1J.er co . . . " n Ime, 'It may be of
<br />,', ,ct:hiSi;err.:mer~lalfishmg or State control of undesirable
<br />,t.~::.;::-F:/ ry 0 great water areas such control will prob-
<br />
<br />'1ikotSfream or lake im " '
<br />7.",".,.,','.,'.'.,'...,-",. ' pro' ement can be suggested
<br />ow suell an attem t ld b' ' nor can
<br />;iil,jliec-&he. pcou e easIly carried out or be of
<br />.,." '~:ch . ry " ,
<br />..ii1Vl;ti, ,1$ still embryo' h . .
<br />. ..:teas full .' mc, .as great potentialities. It
<br />""<ibrlah"an extent as poss1~le with the reminder that
<br />~I11'clna .~ve much more pressmg needs for investigation,
<br />',"" ,> Yf .', J r form of management sugO'ested' th
<br />ee 0 a set of l' . 0' IS e con-
<br />. om' Th regn atlOns whIch are uniform in both
<br />,-,',~lme. e,-in,Iat'L~ d~ to~es suggeste~ here differ somewhat from
<br />:..:o~=:., "LUS 18rlct, and are m .
<br />?~:vegueinother parts of C rf so~e respects m~re len~ent
<br />'{)~ what is known of th ~,11 or~lla, As ~ar as IS pOSSIble
<br />,rM, and are ' . e 10 oglC!l1 req~rements of the
<br />_.-~lJ.ermen ana: ~~mpatIble as pos.'SI,ble WIth the expressed
<br />}~i.neeonr knowledO': p~ece~~nts w!llch. have already been
<br />.', .;.elat]ons-of fi h t'= fi o{ mdlvlduallife hIstories is still sliaht
<br />_,~pJ1,_~ized tha; theO su~apasnteddfifsh to fifsherman still not ;ell
<br />>,:.Ln.e 'sh ul eo - arms 0 managem t 1
<br />".,y, 0 d be chanO'ed a' 0 lId en are on v
<br />~"C:L , . ' 0 ~ ur mow e ge of the fishery grow~,
<br />
<br />Tf",,~'UMMARY OF RECOMMENDATIONS
<br />~----",,~'- .
<br />
<br />~~t:a district. alon.g t~e lowe.r Colorado River in which
<br />~~3~~,'f,:,' or CalIforma lIcenses IS permitted. See p, 197,
<br />
<br />.iltJ~~}ame fishes or forage fishes.
<br />
<br />i;;:.>:C:_~;-
<br />.~'~;:1~~roughout the year for all fish.
<br />'.:'X;h,its
<br />
<br />;b.~~~10~~sh: n?t to ~xceed 15 pounds and 1 fish daily or
<br />.,,,~~~m SIZe lImIt 10 Inches (total length), ,
<br />
<br />:.i~"",...,.'
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