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<br />but have f;.:i1ed to stem invasions of cichlids."K It is likely that
<br />introduced Cich/a, being larger and more predaceous than other
<br />resident alien cichlids, \vill impact the centrarchids to a far
<br />greater C\tent, in this instance through predation. This' 'trade-
<br />off" was recognized in the proposal. It remains to be seen if
<br />(CiCNiI will provide an effective control of other introduced
<br />cichlids, and thus be viewed as a good introduction, or be the
<br />"final blow" to many species of alreadv stressed native fishe~
<br />i:1 these canal systems.
<br />There has been no thorough study of the taxonomy of the
<br />genus Cichla. Olher names (beyond C. ocelloris and C. 1('_
<br />i!lI!lLl"i.l') ~irc recognized, there arc probably undescribed species,
<br />and ther", has been at least one misidentification. Ringue1et et
<br />aJ. c; reported Cichla from the Paraguay basin of Argentina
<br />(Formosa) at about 260 SLat., but that report was based on
<br />tile assumption that Ilc!w/'lll's c!wcOCI1Si.1 is ;1 Cichla. which is
<br />not so. Cichla docs not occur in the Paraguay or Parana basins
<br />and is restricted to the Amazon system 7() This suggests that
<br />tloe genus lacks the genetic spcctrum to adapt to colder tem-
<br />peratures [han predicted by temperature tolerance tests, but this
<br />factor wi:; no\'.' be tested in the connected waterways of south-
<br />eastern Florida. The possibility exists, although perhaps remote
<br />in this ins::ll1ce, that all specimcns im[Jortcd and released may
<br />!'(), be or the species reported. Florida obtained its research
<br />and intrccbetion stocks from Guiana, Brazil, and Peru, and
<br />~-run: specij;1ens confiscated in Florida ane! later sent to the
<br />Tex;le; Department of P:!i-ks and Wildl i fe. (,5 We remember two
<br />i!!sUnces. both involving tilapias, and another with a marine
<br />fish (see below), where the species reported to have been im-
<br />pOjLed tumed out to be other species.
<br />:'\. jurisdictional problem may have occurred with this intro-
<br />c''Jction, as has often happened in other slates. Releases of both
<br />s;;e~ies of Cichla were made into an area from which earlier,
<br />1Ii1sanclioned. private introductions and accident;]1 escapes es-
<br />l;ibli:;hec! :wel subsequently invaded Evergl:ides National Park.
<br />National P3.rk Service (NPS) managers and biologists arc
<br />cbrged \\'ilh managing environments without nonnative spe-
<br />cies, fast becoming a difficult if not impossible task in several
<br />NPS llilits.".72 Should adaptation occur [0 temperature spectra
<br />present beyondlhe sites of introduction in southeastern Florida,
<br />it is highly prob3.ble that Cichla will enter Everglades National
<br />Park, compounding problems that this unit is already experi-
<br />encing with exotic fish invasions.
<br />In another introduction of peacock cichlid, in Gatun Lake,
<br />Panmna, in 1965, the species "effectively eliminated six of
<br />the eight common fish species and drastically reduced a sev-
<br />enth. "7' The study further demonstrated a chain of events
<br />through the ecosystem, including perhaps an increase in mos-
<br />quito populations because of the efficiency of CieMa in re-
<br />moving sm;]1I fishes. The Gatun Lake study certainly merited
<br />(:md still merits) close scrutiny hy those I\'ho would introduce
<br />Ci,-li!iI elsc\\'hcrc~. The peacock cichlid h:ls been sucl"Cssfully
<br />
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<br />
<br />Reviews In
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<br />established in rcservoirs in Hawaii7' and Puerto Rico,7-' where
<br />no serious management problems have been reported, probably
<br />because both areas mostly lack a native inland .fish fauna and
<br />other introduced sport species have so far remained productive.
<br />Having no negative impact to date, however, docs not infe]
<br />no negative impacts forever; introduced species have often not
<br />expressed adverse effects until several decades following in-
<br />troduction,7(' a factor that appears to have escaped the attention
<br />of many managers and biologists.
<br />
<br />VII. TEXANS THINK BIG
<br />
<br />The numerous reservoirs in Texas, many constructed for
<br />cooling effluents from power plants, have provided many and
<br />continuing challenges to the Texas Parks and Wildlife De-
<br />partment. Texas preceded Florida in introducing Cich/a to its
<br />waters/4 but conditions beyond the receiving waters there are
<br />very different from those in southeastern Florida. First, there
<br />is little probability that Cichla that escape from heated reser-
<br />voirs into tail waters could survive and become established due
<br />to cold temperatures experienced during winter months. Sec-
<br />ond, should the experi ment with Cich/a not prove successful
<br />or become detrimental to other fishes. periodic shutdowns of
<br />pO\ver plants for maintenance could be scheduled for winter
<br />months and a total kill of "tropical" fishes in the reservoirs
<br />assured. Texas received its stocks of Cich/a in 1975 from
<br />Colombia and from the Florida Game and Freshwater Fish
<br />Commission, and putative hybrids of C. oce!/oris X C. te-
<br />mellsis from a hatchery in Brazil.'"
<br />While Texas did not exactly follow the 1972 position state-
<br />ment of the American Fisheries Society prior to releasing two
<br />nominal species of CieMo into reservoirs, it did examine them
<br />for diseases and conduct research on these exotic fishes in
<br />closed systems prior to introduction. Nevertheless, their record
<br />kel'ping ;IS to what species they introduced into reservoirs was
<br />poor. _14 None of the introductions was successful; the few res-
<br />ervoirs that allowed Cich/a to overwinter became too hot in
<br />the summer to support them. The effort was described as a
<br />"total failure" .'('
<br />Other fishes introduced in recent years to Texas reservoirs
<br />involved numerous, primarily marine species, as noted above,
<br />including red drum, black drum, snook (Cl'lllropOIl/I/S ftl/de-
<br />cill/otis). Atlantic croaker (Micropogol/ias I/l/dl/lafUs). s()uth-
<br />ern flounder (Paralichthys ll'tllOslig/1/a). and tarpon (MegalofJs
<br />(l(lallliel/.l). I n a disturbing number of introductions in the U. S.,
<br />fishes rele;lsed into "new" (to them) waters have frequently
<br />contained species other than the intendcd species.-" In Texas,
<br />a goby and a needlefish have necome established in inland
<br />waters as a result of havin)! been mixed with introduced game
<br />fishes.
<br />Prob;thly bCl":luse of inlrodlll"lions of Nile perch (I.lltl's lIil-
<br />o/iclIs) into sevl'l';d African lakes in the JlJSOs ;tnd 11)()()S.
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<br />Volume I, Issue 1
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