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<br />L<I\(I\. hy reducing the prey number and duration of the 2007 razorback sucker trials, we may
<br />1'1""" Ill!ie'l\ Illtl'ITlljltl'd ...ccinp the full benefits derived from treatment. We had four trials that
<br />I ,~::I, Iii ,iUI.l111111111 \\h1\.11 wc !\l',( S predator-\avvy, exercised fish; 13 predator-naIve,
<br />,. \ :. ",'ci II,IL .I11\l I () l\lI1lml fi\h. The predator-nai've, exercised fish showed a 19 percent advantage
<br />"\ \'1 1111' l\ 111\!\ II II\h. \\hich wa\ \imilar to our 2006 findings (22 percent). However, the full-treatment
<br />11...11111 t!lO'L' npcrI/l1cl1ts out-performed the control fish by 50 percent. This is an extremely small
<br />:11:11111\'1 (11 ,:!l"'L'I\ .111(111" and 11lIght simply be an anomaly; however, the trend certainly is intriguing and
<br />1:11'>\.... .\ddlll\ll1al que\ll\lnS and possibilities.
<br />
<br />Management Significance?
<br />th'...,' li''''lIll' ...11C'Pl'\! d gldring prohlem facing: repatriation programs. Five decades ago, Miller
<br /><,',i II" ,i,." i','I)III\C\ 111 "'111\ 1\:11 l,lIc's between wild and hatchery-reared cutthroat trout was
<br />'.1 ., I' .'!'llkl' I'! :l,JllIIIII ...\'iL'Cllllll dnd Ihat hdlcheries might be better served (economically) to
<br />Illlurpuralc niltUlillselectlOn forces in the culturing process. To survive, stocked fish must not only
<br />,Ivo,d predators, they must also out-compete resident prey for food and space. This may be difficult for
<br />fish that are typically predator-na'ive, fed commercial feeds, and have no experience with foraging for
<br />natural foods or utilizing complex environments. Poor stocking survival during the past two decades
<br />suggests something is missing in the culturing or reintroduction process. These problems have been
<br />reported worldwide for marine introductions and are now receiving more recognition for freshwater
<br />programs (Svsasand and others, 2000; Wisenden and others, 2004).
<br />Therc <lrc \e\cral excellent papers regarding the need and potential merit of incorporating life-
<br />,klii 11!\111111.c: 111 dqu;ll'uIIUIC prugr~lIm. Brown and Laland (2001) provided a review paper that focused
<br />UIl thc 1.".\1Il' III \llcial learning skills of hatchery-reared fish. A second paper by Brown and Day (2002)
<br />...tlnsed thc need to "shift from husbandry to improving post-release behavioral performance." Both
<br />IJdpCI'" Su~~c\led that large increases in survival of hatchery-reared fish were possible. The main
<br />ill ,.jl!l'Ill III 1\',1 11l~ lhc,e [heoric\ has been the large-scale treatment of fish and the practicality of
<br />,I'II\illlllll~ {\....h lllldn licit! condillons. Mirza and Chivers (2000) conducted field tests for brook trout
<br />l\ti/:dfl/lIl){!I///lIUlis) and chain pickerel (Esox niger) and found measurable benefits for tests
<br />c\'lillu\lnl III Id!'t,'l' SII('<l11l enclo\ures. A similar approach testing survival in hatchery ponds containing a
<br />..., \ "~I 1',\',I.\I('1/i"\'\ l\1111111l111ilV provide\ an alternative approach.
<br />
<br />Wha!ls Happerllng III the Wild?
<br />i 1\I'IV I.. \ l'l: !lltk 1111ll1'lll<lIIlHl available regarding what is happening to razorback suckers and
<br />!)\'11\ 1.\11 :ilklll1l': dre "tllcked One lilc[ Illost can agree with is that very few fish are contacted by field
<br />lJCW" SOl1le hiologis[\ \uggest we simply don't know where to look; however, the evidence to date is
<br />qUIte di\lurbmg. Telemetry studies suggest stocked suckers disperse rapidly, seeking out someplace to
<br />hide (Mueller and Marsh, 1998).lf that is typically the case, this dispersal may literally prevent them
<br />from experiencing a predation event until it is simply too late. It is quite possible stocked fish disperse
<br />and are simply picked off individually before having an opportunity to learn what their predators are.
<br />Newly stocked fish may literally swim into the "lion's den" as a result of current culturing practices.
<br />Thl.\ l1lay heir explain ob\ervations by Marsh and Brooks (1989) of the rapid and complete loss of
<br />:oung razorback sucker\ during a stocking event in Arizona. They estimated it took catfish less than
<br />four days to decimate an entire stocking of hundreds of fish.
<br />Hatchery fish appear to have the physiological tools needed for defense; they simply don't know
<br />how [0 use them. Being raised in a monoculture with the absence of other fish, including predators, and
<br />III .111 cn\ironl11cnl sterile of color, structure, or flow makes them naive and highly vulnerable to their
<br />U\\1l luriu\ity and predators. Other researchers have demonstrated that the release of fright pheromones
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