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Aquatic Ecosystem Health & Management Publication details, including instructions for authors and subscription information: http://www.informaworld.com/smpp/title~content=t713393886 The freshwater habitats, fishes, and fisheries of the Orinoco River basin

To cite this Article: Rodríguez, Marco A., Winemiller, Kirk O., Lewis Jr., William M. and Baechle, Donald C. Taphorn , 'The freshwater habitats, fishes, and fisheries of the Orinoco River basin', Aquatic Ecosystem Health & Management, 10:2, 140 - 152 To link to this article: DOI: 10.1080/14634980701350686 URL: http://dx.doi.org/10.1080/14634980701350686

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The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. © Taylor and Francis 2007 Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 O:10.1080/14634980701350686 DOI: qai csse elh&Management & Health Ecosystem Aquatic Introduction rlrsucs qai aiasi h ai support basin the in habitats Aquatic resources. ural possibly other, fishery. and the collapses stock in of Stricter changes likelihood opportunity. irreversible, the the reduce given would if regulations quickly recover fishery current can stocks of enforcement fish and exploited, lightly satisfy only or to unexploited are insufficient relative currently the modifying is drastically is basin fishing the and ab low in habitat is regulations fishes fishery by to of threatened Compliance status needs. increasingly management conservation are and resources habitats, diversity aquatic of critical understanding but Orinoco hotspots, Scientific the state, perturbation. hydrological of pristine and regions relatively pollution, Large overharvesting, a fishes. destruction, ornamental in for still trade are commercial research of serious basin decades no despite underdeveloped is is region There the promotion. in culture sustainable and Fish annual tons. that metric indicate 45,000 estimates – Current year. 40,000 and of is times yield morphology, different of at markets deal functional fish great the affinities, in a found habitat species encompasses distributions, species, geographic 1,000 of some r includes terms which species, in fauna, aquatic diversity commercial, fish and ecological The support terrestrial fishery. numerous habitats, and the for floodplain of habitat support biodiversity duration provide and and and of terrain, amplitude agricultural riverine the conservation fertile regulate basin, floodplains maintain the major Orinoco floods, three in basin’s The the roles fisheries. In subsistence key and Congo. sport, play the forests, and riparian Amazon including the after discharge by poutv n edn taeis h rnc seyi tl utseic ihaon 0different 80 around with multispecific, still is fishery Orinoco The strategies. feeding and eproductive 2 clg n vltoayBooy et fWllf n ihre cecs ea & nvriy 28TAMU 2258 University, A&M Texas Sciences, Fisheries and Wildlife of Dept. Biology, Evolutionary and Ecology 1 nac,pplto tutr,addsrbto ffihsok.Hwvr ayscoso h rnc basin Orinoco the of sectors However, many stocks. fish of distribution and structure, population undance, h rnc ie ai savs eevi fnat- of reservoir vast a is basin River Orinoco The Keyw third ranking world, the of rivers great the of one is Colombia and Venezuela of River Orinoco The D´ 3 rfso n ietr etrfrLmooy oprtv nttt o eerhi niomna Sciences, Environmental in Research for Institute Cooperative Limnology, for Center Director, and Professor ac .Rodr´ A. Marco preetd hmebooi,Universit´ chimie-biologie, de epartement ords: 4 h rswtrhbtt,fihs n fisheries and fishes, habitats, freshwater The NLE,Boeto ead aaa,Gaae saoPruus,Vnzea3310 Venezuela Portuguesa, Estado Guanare, Cavacas, de Mesa BioCentro, UNELLEZ, qai eore,cnevto,eooy aaeet etoia,flopan Venezuela floodplain, neotropical, management, ecology, conservation, resources, Aquatic ∗ orsodn uhr a:(1)3658;Emi:[email protected] E-mail: 376-5084; (819) Fax: author: Corresponding ıguez, fteOiooRvrbasin River Orinoco the of n oadC ahr Baechle Taphorn C. Donald and nvriyo ooao ole,Clrd,USA Colorado, Boulder, Colorado, of University , 02:4–5,20.Copyright 2007. 10(2):140–152, 1 olg tto,T 79325,USA 778943-2258, TX Station, College ∗ ikO Winemiller, O. Kirk Qu´ eduQu´ bc 9 H,Canada 5H7, G9A ebec, bc` ebec 140 aT itvs uha h rnc rcdl,teArrau the crocodile, Orinoco ini- the conservation as such for tiatives, value emblematic of various species including and biodiversity, fisheries, tremendous subsistence harbor and sport, commercial, r ois-Rivi`  C 07AHS SN 4348 rn 5947 online 1539-4077 / print 1463-4988 ISSN: AEHMS. 2007 rs 31bu.dsFre,Trois-Rivi` Forges, des boul. 3351 eres, 2 W limM ei,Jr., Lewis, M. illiam 4 eres, 3 Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 rnc basin Orinoco the of fisheries freshwater and fauna, fish freshwater resources, freshwater of Overview soeo h ra ieso h ol,rnigthird ranking world, the of rivers by great the of one is luilzns a ihana rcptto (1,000– precipitation annual and high has montane zones) Andean alluvial of portion western and Shield m. the 3000 above in elevations rise at zone Orinoco montane the Andean of headwaters northern western the and deposits, these beyond of watershed, periphery the the Toward alluvial origin. by Andean of kilometers deposits hundred several of distance rock. To basement crystalline weathered thoroughly of Bol´ of al- states is the in Shield drainage Guayana the the by for of accounted entirely side most southern The Andes the 1). of (Figure drainages coastal by west and north the margin southern entire its by on bounded is basin The inkm lion Interciencia, journal the of issue V special a as in 1990 published rivers American South large on sym- posium a of proceedings the (1990), described al. et are Weibezhan in ecosystem compo- River Orinoco biotic the and of nents environmental The Congo. the s utr,icuigcretlegislation. current including and culture, fisheries fish (3) and conservation; systemat- its and fish ecology, stem, ics, (2) main floodplains; Orinoco their and the (1) tributaries, of on primarily habitats is aquatic focus The the area. 71% basin total for the accounts of which Venezuela, the within to region attention particular with basin, River the Orinoco of fisheries and fishes, habitats, freshwater the on rising. are perturbation hydrological and pollution, overharvesting, destruction, threats habitat state, from pristine relatively a in still are and pres- sures anthropogenic mild his- to been only have subjected basin torically the resources. within well, its areas vast from As Although sustenance otter. indigenous derive many that river by cultures inhabited giant is basin the Orinoco the freshwa- and manatee, dolphins, Caribbean ter the turtle, sideneck l 56,adLwse l (2000). al. et Lewis and 15(6), ol. h i er,amjrAao rbtr,adon and tributary, Amazon major a Negro, Rio the h rnc ie fVnzeaadColombia and Venezuela of River Orinoco The h otenpr fteOioobsn(Guayana basin Orinoco the of part southern The h rnc ie ai xed vr11mil- 1.1 over extends basin River Orinoco The hsatcesmaie h tt fknowledge of state the summarizes article This icag 3,0 m (38,000 discharge h ot n et h rnc sflne o a for flanked is Orinoco the west, and north the 2 n oes8%o eeul’ territory. Venezuela’s of 84% covers and vradAaoa,wihconsists which Amazonas, and ıvar Rodr´ 3 ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez s − 1 ) fe h mznand Amazon the after ,0 my mm 4,000 fteetr ai 200m y mm (2,000 basin entire the precipitation of area-weighted The semiarid. are north hs pce eancmo nrvr ftellanos, the of rivers in common remain species These sum ( P. rayados ( bagres payara the the include armatus fishes sport ular challenges w conservation and distribution, ecology, h aoe,o ecc ihis( cichlids peacock or pavones, the time and region year. to of according varying harvest the in v Ciudad Bol´ Maripa, Orinoco, del Caicara Bruzual, alito, Guasdu- Ayacucho, Puerto with in located fisheries, markets major commercial support also and The wetlands, tributaries lakes, llanos. marginal western its at and the River centered in Orinoco Apure is de Venezuela Fernando in San The River. fishery Orinoco inland the largest in fisheries commercial of llanos. Venezuelan the of fishes the of the geography from some them include ov of 2004a) an provides (1993) most Machado-Allison al., basin. Orinoco fishes, et freshwater Lasso 1,200 1997; (Taphorn lists al., species et published latest The North 1991). (Winemiller, Africa in and in America, habitats Central observed comparable America, that in than assemblages greater fish high is the (“Llanos”) of assemblages plains fish local in encompassed diversity morphological The strategies. feeding and reproductive and di- morphology, functional ecological affinities, of deal great v a encompasses basin lower m. 12 Orinoco approximately the is for stem levels main water in range The annual March). (February, months lasts two that approximately plateau a to thereafter decrease and August the w throughout discharges River shows seasonality. basin strong Orinoco the in Precipitation grassland 2). savanna (Figure primarily is watershed the of half forest, moist tropical al., of w consist et (gen- south) (Lewis watershed the the to basin erally of Amazon portions wettest the The of 1995). that to equal reyo pce r xlie,wt oiatfishes dominant with exploited, are species of ariety riyi em fgorpi itiuin,habitat distributions, geographic of terms in ersity r umrzdb ieilr(01.Ohrpop- Other (2001). Winemiller by summarized ere trhdices rmapoiaeyArlto April approximately from increase atershed eestelweeainprino h northern the of portion low-elevation the hereas tigrinum riwo h aua itr,eooy n bio- and ecology, history, natural the of erview h otipratsotse nVnzeaare Venezuela in sportfishes important most The status the reviewed 2002) 1989, (1982, Novoa Orinoco the of fauna fish rich taxonomically The vr iddGaaa n arna.Agreat A Barrancas. and Guayana, Ciudad ıvar, ,adcjr ( cajaro and ), ) n ag ieoi afihsincluding catfishes pimelodid large and ,valent´ ), − 1 ,weestealva oe fthe of zones alluvial the whereas ), hatcpau hemioliopterus Phractocephalus n( on suoltsoafasciatum, Pseudoplatystoma rcyltsoafilamento- Brachyplatystoma − 1 Cichla )i s approximately p..Their spp.). Hydrolycus 141 ). Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 142 iue2. Figure S.K. by provided kindly was delta internal the on inundation the University). of extent State The (Michigan delta). Hamilton Orinoco and floodplain, fringing delta, (internal 1. Figure a fteOiooRvrbsn hwn ao egahcrgos rbtre,cte,adtetremjrtpso floodplain of types major three the and cities, tributaries, regions, geographic major showing basin, River Orinoco the of Map a fteOiooRvrbsn hwn h itiuino ao eeaintypes. vegetation major of distribution the showing basin, River Orinoco the of Map Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 n t tributaries its and River Orinoco the of Habitats Basin the Orinoco in science freshwater of State eet aesta yial r ihytransparent highly coarseness are high typically to that waters moderate beneath An- of the substrate of flanks over the des from gradient high at flow size invertebrates. benthic and for diversity fish habitat both reduces often which is mobile, substrate and the fine Also substrate. the ir- to transmit radiance efficiently not pri- do are colored, they darkly because marily and, of rainfall because of deep abundance emerge generally the are tributaries but Major canopy, the well. from as waters clear some are although waters”), matter (”black origin predom- organic terrestrial dissolved are of by south colored the darkly edges from inantly the waters from The flow tepuys. that rivers of and streams of excep- tion notable the with gradient, low relatively have and canopied predominantly are Shield Guayana large the one only Caron´ the is on (Guri, there reservoir floodplains; on are ge- except Lakes order. and rare, stream climate by partly by and partly omorphology vary organisms aquatic o ocr eas prtosaeo relatively a on are scale. small operations because concern jor ma- a be region. to seem Amazonas not does the overexploitation However, from Colombia made is via exportation illegally and all unknown of an proportion large because possibly reliable not are statistics Trade be- exportation. to probably hurdles administrative persisted, of companies, cause not few have a ventures by these wild but the from harvested have been fishes Ornamental Venezuela. in fishes mental ( morocoto mus the with hybrid its and e w macropomum soma anglers. ( palambra hrcd,teslao ( migratory Two saltador the Amazonas. characids, and Shield, Guayana oi tlpa”(includes “tilapias” xotic ihdmntscmeca rdcin n the and production, commercial dominates hich To other and fishes to available habitats Aquatic hr sn eiu omriltaefrorna- for trade commercial serious no is There F ) Sarotherodon s utr etr nteccaa( cachama the on centers culture ish a enpatcdfrmn years. many for practiced been has h ot,tiuaiso ml ointermediate to small of tributaries north, the rcnwhitei Brycon p..Cliaino ahm and cachama of Cultivation spp.). ) Rodr´ rvee nGnly 1990), Ginelly, in (reviewed ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ,aeas oua s with fish popular also are ), amnshilarii Salminus ) h ml tem of streams small The ı). T ilapia ircu brachypo- Piaractus , Oreochromis ) n the and Colos- , h rnc ai Lwse l,19;Fgr 2). Figure 1995; al., ( et within delta Orinoco (Lewis The floodplains basin. basin of Orinoco Orinoco types the the major of three flora are and There fauna aquatic the physical, characteristics. contrasting biological and sharply mix- chemical, of a types is water of Orinoco ture the tributaries, dis- white-water black-water both and and receives suspended it Because of solids. amounts solved small Shield, only Guayana yields the through w primarily rapid flow by ters produced solids w suspended and solved diversify that waters habitat. aquatic off-channel often to and flow connected low are at growth algal benthic produce can that channels stream shallow of development the promotes channels the in material amount alluvial large moving the of and area unit per smaller runoff the of but amounts 1988), can Lewis, waters” and (Saunders “white high these be of low. inverte- are turbidity aquatic gradients seasonal the The and plains, alluvial fishes the both On suitable brates. of is diversity habitat a benthic for the Thus, light. tercepts e raim utcnedwt titylacustrine strictly with contend of must aquatic other percentage and organisms small fishes a Thus, maximum. to annual time its this at shrinks habitat space days), 100 (approximately drought seasonal Although w 2000). al., et Valbo-Jørgensen 2000; al., et (Lewis fishes and invertebrates floodplain for habitat well. as present v areas, uncanopied repens the palum Within season. surrounding during dry the isolated are the with but water, high and at are areas other canopied They each lakes. floodplain with called joined be can that sions fringing depres- topographic the 2300 to of corresponds floodplain portion uncanopied the The on canopied. than 79% approximately north is floodplain the fringing The on south. wider considerably is but oteAue(prxmtl 0 m,afringing a km), ( 600 (approximately floodplain Apure the to known. is little very which about floodplain, this g dissected and b deposits deltaic overlying floodplain cp ttmso ihs o,we ubdt in- turbidity when flow, highest of times at xcept sua ln,atog te aclrpat are plants vascular other although plant, ascular ya asspeoiaei h rswtrprin of portions freshwater the in predominate rasses ahrn nteAds ncnrs,tebakwa- black the contrast, In Andes. the in eathering trprit ihntelksdrn h prolonged the during lakes the within persists ater ihhsbe etee oetnieyta it that extensively so weathered been has hich lopan r aiaso ra osqec to consequence great of habitats are Floodplains dis- of amounts large contain waters white The ln h anse,etnigfo h delta the from extending stem, main the Along ag ubro itiuaycanl.Aquatic channels. distributary of number large ∼ ,a 0 km 700 n P aspalum qai 4gas stedominant the is grass, C4 aquatic ∼ 100km 21,000 2 ) nopse ohbanks both encompasses rvdsciia physical critical provides 2 ) osssmil of mainly consists P 143 as- Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 ag nenldlana h pr ie ( River Apure km the near delta internal large are lakes inorganic. floodplain and fine the primarily of substrates oxida- the high rates; of tion because is floodplain sediment the organic on of negligible Accumulation (Lewis anoxic 1995). become al., may et which environments Amazon, similar the than of habitable more are thus of and oxygenated, are environments typically in- floodplain Benthic Orinoco the the inundation. during full large of exploit at may terval floodplain also the but on season, resources dry the of conditions 144 hna n bv h n ee si oeusual more is as level 2nd rather the levels, above trophic and 2nd at and than 1st the derived thus from is mostly production of Fish most 80%. her- remaining for the on account or which invertebrates, production, bivorous fish for accounts of that al- 20% carbon on approximately of source directly nutritious feeding a for gae, adaptations have plain by in- ve and fish both of production carbon, available for total account jointly litter and macrophytes although Strikingly, 2001). al., et (Lewis tracers iso- tope stable through com- analysis been trophic-level ratios with P:B have bined of estimation floodplain of means Orinoco by analysed the the top on by to producers consumers transported primary from matter flows Trophic river. macrophytes, organic and algae, phy- periphytic litterfall, floodplain: and Orinoco the toplanktonic on consumers mary 2003). Winemiller, and Duque al., Barbarino et 1987; (Lundberg stem main the of waters feeds lotic within fishes specialized of community small compar- atively a between Nonetheless, the dispersal tributaries. in for and habitat species backwaters this fish use most the to seem all, in basin at found Orinoco If stem limited. main is invertebrates and and fishes birds for resource food pro- crocodilians. fishes abundant struggling an pools with viding drying anoxic, subside become floodwaters often and rainfall As season. wet the during productive highly ephemeral are shallow habitats These north stem. the main to Orinoco the km of square thousand many aquatic over temporary habitat provides it impounded, where of landscape, much Thus over the spreads stem. and main depressions fills the water the in water of ume w r h anse r mee ytehg vol- high the by impeded are stem main the ard r h hr odli fteOioocnit fan of consists Orinoco the of floodplain third The utpesucso abnaeaalbet pri- to available are carbon of sources Multiple for habitat itself, Orinoco the of stem main the In 2 ertso h odli sspotdprimarily supported is floodplain the on tebrates la abn ayfiho h rnc flood- Orinoco the of fish Many carbon. algal ) htfrsa esnlflowtr oigto- moving floodwaters seasonal as forms that Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ∼ ∼ 8 of 98% 70,000 fteptnilyaalbecarbon. available potentially fraction the small a of such on sus- production of fish means high only taining the is which compression, food chain marked show therefore 2002) Winemiller, (Jepsen the and tributaries of major its webs and Food floodplain ecosystems. Orinoco pelagic in fishes for fOioofishes Orinoco of knowledge of state Current al nsesfut,mcohts la,wood, algae, opportunisti- macrophytes, or seeds/fruits, exclusively on feed webs. cally food of species aquatic range in Some full positions the trophic represent consumer that niches ecological familial the at even poor is level. groups other for knowl- of edge state the whereas 1996), Fink, and Allison g across considerably g varies coverage taxonomic of by g evddsrbtos(hrofe l,19;Lasso 1991; P´ 1991; al., ob- al., et explain et (Chernoff to in distributions made Pre- served been soils Shield. have Guayana lateritic attempts the drainage, or liminary draining the sandy and llanos, of of the pockets portion isolated southern diversity, in the fish high productiv- in relatively low mostly but with biomass, found rivers and blackwater is ity to division clear second in The Mountains. the in Andes originate Apure watersheds whose the Rivers, as Meta such and drainage, the sediment- the of the in portion in concentrated northern whitewaters found is nutrient-rich division and first The type. o g Per- and 1). (Table major Siluriformes, ciformes three Characiformes, within to the fall important orders, aquaculture, most and those including fisheries species, new 85% the but Nearly year. of b), every 2004a, described being al., and are et Venezuela species (Lasso in Colombia fish found in 995 are 627 at 939 which basin of Orinoco species, the the for places estimate richness current species most The 2004b). al., et (Lasso tributary Orinoco in- major basin, each for Orinoco lists the cluding of of fishes update freshwater and of list revision the complete a on collaborated nzd ahascae ihadsiciewater distinctive a with associated each gnized, op,eg,tecrbso iahs(Machado- piranhas or caribes the e.g., roups, some for available are monographs Detailed roups. limited still are groups many for analyses raphical ahcdvsoso h ctyfuacnb rec- be can ichthyofauna the of divisions raphic V W V orkoldeo lh aooy h depth The taxonomy. alpha of knowledge poor nzea se cuyabodrneof range broad a occupy fishes enezuelan nzea n ooba ctylgsshave ichthyologists Colombian and enezuelan ti h rnc ai,tobscbiogeo- basic two basin, Orinoco the ithin rzadTpon 93,btbiogeo- but 1993), Taphorn, and erez Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 segosfre 2 1 12 2 59 1 1 9 20 2 24 27 1 1 1 6 12 2 5 P 12 Osteoglossiformes 1 3 Myliobatiformes Lophiiformes 4 Gymnotiformes 1 Elopiformes Cyprinodontiformes Clupeiformes Charchariniformes rsioms112 314 1 150 1 11 1 12 5 1 1 3 Siluriformes Scorpaeniformes Pristiformes Pleuronectiformes 8 399 species aquaculture 3 1 or Fishery 5 124 2 1 14 2 Species Genera Families 2 1 Characiformes Beloniformes Batrachoidiformes Anguilliformes Order ygahfre 2 1 2 1 1 1 T Syngnathiformes Synbranchiformes T en r togyascae ihlnsaechar- landscape with associated strongly are terns also. listed are aquaculture or fishery to 1. Table W or 2003), w Winemiller, and Duque (Barbarino floodplain rivers in position lateral 2004), (Hoeing- 2003, al., gradients et haus river in position longitudinal according to degrees varying to segregating tributions dis- species with patterned, strongly are assemblages species individual for (Rodr´ documented been have pat- activity terns in fluctuations and daily marked al., space and et 2005), Willis of 2003; Winemiller, and partitioning (Arrington scales time significant spatial small reveal at assemblages also investigated fish been have Most that habitats. in aquatic scarcity species seasonal resource greater of intervals for during spe- allow coexistence feeding to of assumed degree is high fish cialization This fins, blood. or fish mucus, arthropods, terrestrial zooplankton, tadnioms123 2 1 etraodontiformes rioms1 5126 65 15 erciformes tl7 2 995 421 77 otal trtp (Rodr´ type ater nmle,2002). inemiller, ttewtrhdsae s itiuinpat- distribution fish scale, watershed the At ge ta. 90.A agrsailsae,fish scales, spatial larger At 1990). al., et ıguez itiuino rnc s pce mn res aiy n eea(oie rmLsoe l,20b.Seisimportant Species 2004b). al., et Lasso from (modified genera and family, orders, among species fish Orinoco of Distribution ge n ei,19;Jpe and Jepsen 1997; Lewis, and ıguez Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez nsuhr eeul eg,tecria tetra, cardinal the (e.g., Venezuela Pa forests southern Amazonian the in of waters black to primarily restricted Species unpublished). al., et gradient (Winemiller clearwater-blackwater longitudinal associated a significantly with is region basins) and Casiquiare Orinoco Negro/Amazon the the of headwaters of the connecting struc- assemblages (river Taxonomic and fish 2004). of dispersal al., ture wa- limit et (Turner cases to flow other appear gene many features barriers in quality but geographic ter dispersal, cases, fish some limit In rivers streams. lakes, and transparency) low pH, conductivity, (high whitewater high or transparency), high conduc- tivity, and pH (variable clearwater with transparency), affiliated are species ichthyofaunalb of of predictor Suites type strong assemblages. Water particularly features. a quality is water and acteristics trpylmaltum Pterophyllum akae lwp,lwcnutvt,intermediate conductivity, low pH, (low lackwater ra Cichla Brachyplatystoma Brycon c erdnaxelrodi heirodon earciou kneri Semaprochilodus brachypomus Piaractus armatus Hydrolycus hemioliopterus P. tigrinum spp., spp., lgoco squamosissimus Plagioscion oosm macropomum Colossoma ) , r oeie nonee as encountered sometimes are spp., suoltsoafasciatum Pseudoplatystoma n h rnc angelfish, Orinoco the and , Mylossoma Phractocephalus , , .laticeps S. rciou mariae Prochilodus spp., , 145 , , Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 we h ae n daetflopan(Rodr´ floodplain adjacent and lakes the be- movements tween by driven are that abundance in tions fluctua- seasonal strong despite stability interannual 2003). al., et Hoeinghaus F 1998; Jepsen, and miller Wine- 1996a; (Winemiller, reproduction shel- and feeding, tering, water for habitats in of variation availability and to quality response in movements scale assem- fish Local 2005). b al., et (Arrington aquatic shallow habitats destroy and an- create where pulses par- flood regions nual is floodplain pattern in behavioral prevalent this ticularly and basis, seasonal n eals 93.Ms oal r h annual the are notable Most 1983). (Salda˜ Venables, kilometers and hundred several of impor- migrations long-distance most seasonal, the perform species of fishery Some tant 1994). 1990, Lewis, and from way same the in y prey interactions and predators of mor- between outcome lake the because channelizes season phometry dry the in strongly deterministic thus is (Rodr´ structure season Assemblage 1994). dry Lewis, the vol- during shrinking lakes the of in- by ume intensified predatory dry are by the that molded teractions of are onset assemblages the season, at unpatterned largely of lakes seems mode among fish their of with assortment Although compatible predation. most select are may that predators indica- lakes and an intensity, as predation morphometry of lake tor use to able be may species prey avail- Furthermore, cover. and structural of depth ability relative lake between the relationship through vulnerability transparency, affects of morphometry determinant In lake a fetch. as role and its depth to of addition thresholds specific at turbidity occurs to leading sediment of resuspension lakes: w low at ca- Transparency foraging species. individual and of sensory pabilities the to and transparency related to strongly is turn in Vulnerability species. vulnerable prey most the culling by structure assemblage modify Piscivores lakes. clear in on predominate relying vision fish whereas lakes, turbid in dominant light are low to adaptations sensory with fish season, dry (Rodr´ phometry mor- lake pis- to transparency and connecting transparency to relationships civory causal by structured Ayacucho. Puerto of vicinity the the in to north kilometers of hundreds located Orinoco the tributaries of blackwater small in populations isolated 146 ae nflopancek r nune ylocal- by influenced are creeks floodplain in lages a oyear. to ear s sebae nflopanlksso marked show lakes floodplain in assemblages ish tri rdcal eae otedphadsz of size and depth the to related predictably is ater otfihsmv ewe qai aiaso a on habitats aquatic between move fishes Most F s sebae fOiooflopanlksare lakes floodplain Orinoco of assemblages ish ge n ei,19) uigthe During 1997). Lewis, and ıguez Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ge and ıguez ıguez na al iprewti ao rbtr ies(Bar- 1998). rivers al., tributary et Duque major barino within the disperse grad- of then ually upstream end move they the where season) at flood migrations (annual “ribazones” ( mije erici the as such other species several migratory and coporos of schools (November- huge period January), falling-water the During wet- seasonal lands. and rivers rain-swollen in re- the feed then to to and main midriver rivers in these spawn they from where lowlands migrate coporos ripe sea- wet son, early the During 1983). western (Lilyestrom, the llanos of rivers lowland and piedmont the Andean draining rivers between coporo the of migrations n s culture fish and fisheries freshwater of status Current lossoma rnc ie ilslrecthso catfishes of catches large stem ( yields main The River west- the basin). Orinoco in (Apure-Arauca areas llanos other fish- and moro- ern Fernando dominate and San rayados in mije, bagres eries rayados, and Coporos bagres coto. coporo, the such species as commercial major for area nursery tant the in harvests total fishery. for Orinoco limit of upper half an over as production, just fish represents al., which an- et yield, of estimate nual (Lewis Novoa’s supports floodplain value This Orinoco pro- 2001). the fish total on for tons duction metric 79,000 of (Novoa, yielded estimate analysis an production foodweb comprehensive fishery A total 2002). country’s the 3–12% of of between representing harvests tons, annual na- 16,000–60,000 reported Venezuelan agency, the fishery INAPESCA, tional 2000, Between and 1980s. mid 1984 at the in estimated tons were metric 12,000 yields about fishery floods. multispecies annual of The intensity ap- with yields correlated that be noted to pear and River Orinoco metric the for 40,000–45,000 tons of yield annual estimated calculated an previously Novoa migra- prochilodontids. on tory reliance proportional greater pimelodid to large catfishes from the shifts during by expanded accompanied basin 1980s Orinoco commercial the that of fisheries reported (1989) pimelodid Novoa and catfishes. prochilodontids of mar- consists fish harvest the in found k species different 80 around Brachyplatystoma t tdfeettmso er u h uko the of bulk the but year, of times different at ets h etr lnso eeul sa impor- an is Venezuela of llanos western The with multispecific, still is fishery Orinoco The ,mrct,adbge aao,priiaein participate rayados, bagres and morocoto, ), p.,pyr,plmr ( palambra payara, spp.), p.,mrct,plmts( palometas morocoto, spp.), Brycon eoiu frid- Leporinus p.,and spp.), My- Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 ltl rmtecmeca avs,btsok of com- stocks but disappeared harvest, have commercial or the from sizes pletely smaller much caught now at are species predatory (Novoa, largest period The of same 2002). the composition over in- the changed but has actually catch years, has the 25 effort last unit the in per basin. creased catch Orinoco delta, the the of sections On upper the in notable maturation prochilodontids. earlier the and in sizes population in declines the harvest to seines b blocking large with of downstream practice rivers caused have The season, overexploitation. dry severe the fish during Week for Holy demand rivers. for peak smaller with these along conditions, out These fish completely permitting extended, to The and fishers severe range. more mountain is season Andes dry the draining rivers of sections upper the of sedimentation concomitant and deforestation extensive to led has development tural Agricul- 1998). al., et Duque (Barbarino populations prochilodontid their migration of block portions significant that lost canals have irrigation of dams and portions with dykes lower rivers or Highland the tributaries. in Orinoco concentrated the now is shifted has and prochilodontids the scales, for larger fishery At boats. commercial their fill to days more stay and out journeys and longer absent, make to or required are scarce fishers now are species fishes largest commercial the of centers, fishing Near scales. eral erdseishv iapae rbcm aeand rare e pre- become or previously disappeared have because species markets ferred in are common catches, con- from now discarded once and stocks. fish payara, “trash” fish and sidered of catfishes, depletion doradid or Caribes, reduction selective to P b dou- the and destruction habitat by recently pounded Overhar- basin. n Orinoco the in v stocks fish distribu- of and tion structure, population abundance, tive harvest annual al., the et of (Vispo wa half than annually less harvested Slightly fishe 2003). of met- tons 250 estimated ric an comprised species 27 but least rayados, is at bagres River and morocoto Caura the by the dominated of fishery The prochilodontids. xpensive. lnsie vr3 er g n a encom- been has and ago years 30 over seines ylon okdmgaoswt atnt a otiue to contributed has nets cast with migrators locked igo eeul’ ouaini h at2 years. 25 last the in Venezuela’s population of ling sigo ag se ea ihtearvlof arrival the with began fishes large of esting ten fhmncnupinhv responded have consumption human of atterns s h fet foehretn eeal r most are generally overharvesting of effects The sev- at occurred have fishery the in shifts Spatial h seyhsdatclymdfidterela- the modified drastically has fishery The ae ysbitnefishers. subsistence by taken Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez aoe.Five pavones. healthy delta. the still in are herbivores and detritivores smaller fteeoytm nwihte eed Expect- many fa production, depend. high and they profits which integrity extraordinary ing on the ecosystems and serious the species a of native poses exotics to these threat of potential Use wild. the into commercialization. successful to key the are ingredients produced locally and byproducts indus- trial incorporating experi- feeds positive Artificial produced results. mental also has culture cachama, cage the but cultivate to ponds earthen use stations V 1983). (Lilye- Taphorn, Venezuela and of strom region in populated impacts heavily human other this and reduced dams to been due numbers has in characid, migratory is palam- another dams The bra, species. by these routes to damaging migration particularly of Blockage region. has saltador con- a The dam 1996). al., and et (Winemiller over- siltation, struction by and eliminated deforestation nearly been fishing, now has pied- Andean but the mont of rivers in common once was that a about only after destroyed were Reservoir Majaguas Im- heavily. pav´ pressive more exploited Caron´ be to and begun (Caura have rivers) Shield (Casiquiare Guayana Amazonas the and in region) areas remote in pav´ ulations years, recent In access fishers. net good and with anglers areas to all has in Overharvest problem serious predators. a been top as position trophic strat- eg reproductive their of occupation ecosystems, their unproductive of function a probably overharvest, is to this sensitive and highly be to appear lations temensis C. ( three only but sarltv newcomer. relative tilapia, a red variety, is cultivated currently the 1959, Venezuela in into introduced first were tilapias though is mouth-brooders e these of numbers commercial of reproduction culture: the tilapia with for associated appreciation pitfalls little was there Unfortunately, pnie ao nesv,adtm osmn.Al- consuming. time and intensive, labor xpensive, nzeasnete17’ Gnly 90.Most 1990). (Ginelly, 1970’s the since enezuela irtr iehsoysmlrt h oooi this in coporo the to similar history life migratory eaeo lea sigactivity. fishing illegal of decade r yi esaadndteccaai ao ftilapia. of favor in cachama the abandoned mers otsotfihn nVnzeacneso the on centers Venezuela in fishing sport Most eea pce fcliae iai aeescaped have tilapia cultivated of species Several in existence in been have hatcheries Cachama fish sport a is characid, predatory a saltador, The nv lignsigadprna ae n their and care, parental and nesting olving ) nfihre nteAur ie n Las and River Aguaro the in fisheries on pert ewdsra.Pav´ widespread. be to appear Cichla .intermedia C. pce cu ntecountry, the in occur species , .orinocensis C. npopu- on npop- on , 147 and ı Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 nVenezuela in W basin Orinoco the in management freshwater of Survey 148 iuto ih ecretdudrtenwyen- newly 2002). the (Novoa, law under fishery corrected acted undesirable be This might fishery. situation thus the were to and detrimental phases highly migration and during reproduction harvests permitted es- that legislators regulations 2001, tablished and 1999 Between ineffec- results. and fishes, tive objectives of conflicting harvesting with the sometimes regulating in roles and sumed as- have MAC (MARNR) the Environment the Both of neglect. Ministry the official fish- to these led of has value eries low relatively tra- the using gear, fishers ditional rural by captured are Venezuela in in- and widespread few of too environment an are deterrence. create nets these to but confiscating frequent motors, often boat netters, and and illegal en- citations Law of occasional country. arrests make the sec- entities throughout all forcement by society violated of often tors are regulations Unfortunately, effort. harvest and gear fishing and of permits, regulation of issuing assessment, stock including bl extreme by river the into floods. may washed lakes the sporadically in be treat- accumulated remedial pollutants ef- Without the discharged lakes. ment, natural legally into has in- fluents others, aluminum among the dustry, en- and from rehabilitation exemptions provides vironmental which clause ther” “grandfa- wa- a natural contain regulations into these However, release efflu-ters. to of prior solids) treatment ex- created (BOD; for ents were standards an regulations the as new tightened 1995, that conservation In with aim. qual- plicit discharges water and manage other ity and to CVG by institutions efforts concerted governmental has of there lack Historically, a resources. been develop- water urban and ment, tourism, mining, forestry, agri- culture, in plan- projects implementing for and responsible promoting, ning, is lower agency The the basin. in Orinoco management environmental in player raci´ e trqaiyadfihre laws fisheries and quality ater lhuhmr hn7%o l seyharvests fishery all of 70% than more Although responsi- is (MAC) Agriculture of Ministry The Ar nVnzln eGaaa(V) samajor a is (CVG), Guayana de Venezolana on o aaeeto h seisi Venezuela, in fisheries the of management for e inldvlpetaec,teCorpo- the agency, development gional Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez n csse management ecosystem and conservation biodiversity with Linkages utr n aternhn r xesv nthese in extensive are ranching cattle and culture Anzo´ oee,adGu´ Andes and the Portuguesa, Cojedes, border Barinas, Apure, that north, the states in mountains the exten- in high once regions and the regions plains are piedmont Andean basin forested corre- Orinoco sively is deteriorated the fisheries most in The local regions presence. of human state with the lated and fishes status conservation of the physically, unaltered tively mining. and from development, prevent- watersheds urban forestry, the by of mostly degradation large-scale biodiversity ing mainte- aquatic the of to nance contribute Protected probably Parks. therefore National altogether areas the or within minimal even is lacking, areas protected in fishing delta. Orinoco the and basin W Orinoco the of part ern V Refuges, Faunal F Monuments, Na- Natural conservation, Parks, to tional relevant of most categories areas The protected monitored. or not managed are actively they because protection though, nominal areas, only afford these of Most of territory. country’s thirds the two cover administra- collectively which special regime), under tion protected areas of or network (ABRAE, a areas of existence the by fostered economi- areas. as these even around develop activities state profitable cally natural a in key maintain habitats to aquatic promoted be could landowners, the Similar by conservation viable. encouraging schemes, economically management proven cavimorph (large has capybaras rodents) and for cattle managed of of lands ranching development private the on ventures llanos, ecotourism the needs In local to constraints. adapt and and to for likely account more they be if will succeed basin aquatic the in preserving biota and for habitats Strategies sup- fishery. and the for species, ports grounds aquatic breeding and or terrestrial pro- numerous feeding and terrain, refuge agricultural vides fertile of duration maintains and floods, amplitude of the the conservation example, regulates For in floodplain basin. role Orinoco the key in a biodiversity play forests, parian ua eevs n ishr eevs(6 of (26% Reserves Biosphere and Reserves, aunal nzea ertr) r ocnrtdi h south- the in concentrated are territory), enezuelan t oeecpin,srelac n oto of control and surveillance exceptions, some ith lhuhms fteOioobsni rela- is basin Orinoco the of most Although is Venezuela in habitats aquatic of Conservation ri- including habitats, floodplain and Riverine tgi oaa,adDlaAauo Agri- Amacuro. Delta and Monagas, ategui, rc,adteesenpan of plains eastern the and arico, Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 aaeetscesstories success Management l u tpe,adilglntfihn a increased has fishing net illegal and stopped, have but patrols all these Venezuela, in conflicts social and provided which areas, ad these patrol periodically able was to from Nacional fuel Guardia the and groups, motors, sportfishing boats, of donations by aided pav´ of Protection laws. request fishing of to enforcement motivated increased sufficiently sportfish- were local interests cases, ing both is In company. mining power access government-run and where a Reservoir, EDELCA, by Na- Guri controlled Luzardo and Santos Park, of ex- tional border of the couple forming a River, cite pav´ to the able ceptions: only are We natural their habitats. or fishes freshwater of stocks enhanced or protected have that practices management specific euti aia etuto n ihby-catches high species. non-commercial and of destruction discarding and habitat of which in gear, trawling fishing result unselective include of use biodiversity and channels to the threats in delta, reductions causing also com- av that is evidence netting is mercial commercially There larger in quantities. the present attractive sizes that longer no indicate mesh are seines individuals Declining commercial catfishes. of the decline large in the of to contributed stocks and increased efficacy greatly has fishing nets of cast and use motors the outboard still fishery, Though technology low catfishes. n almost a predatory as for large classified the overexploitation various of fishery, to all Orinoco point the predators). in indicators attained has large been perhaps not yield (including sustainable maximum Although structure of trophic preservation to attention ad little with harvest, on by mercury. the with Bol´ and chain water food of aquatic the rivers contaminated has many Amazonas in and shape. better mining in are gold rivers However, and vegeta- less suffered the has Shield, tion Guayana the and draining state rivers Apure the southern 1996). settled sparsely al., still et the In (Winemiller of forests 80% existing over reached original has deforestation and regions lnsie uldb ml ot rcne with canoes or boats small by pulled seines ylon rg ieadaea auiy nteOrinoco the In maturity. at age and size erage iv ertal,Vnzeapoie e xmlsof examples few provides Venezuela Regrettably, osraino idvriyhsbe hindered been has biodiversity of Conservation nams xlsv ou yfihre managers fisheries by focus exclusive almost an eg nsok a h rmr ocr.Sometimes concern. primary the was stocks on rie sey eei nert,adbalanced and integrity, genetic fishery, ersified e fdtrec.Floigrcn political recent Following deterrence. of ree nsotfihre fteCinaruco the of fisheries sport on Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ıvar ssota eae(.. a aausReservoir Majaguas Las state). (e.g., Cojedes decade in a intervals as over short fishing as illegal by depleted pav´ been production have formation, initial those reservoir the after than following burst and, regulated rivers, better the no of are fisheries the these Unfortunately, having densities. areas population in human people highest to resource valuable fishery a new bring reservoirs These Coastal ranges. and mountain Andean the of regions piedmont within New pavones. the especially pav´ fishes, sport adapted g negative have to certain populations. is on impact this and Venezuela, al- pav´ to in of changed recently fishing was commercial law low The areas. both in ov Summary management: and Science Conclusions n dto fteVnzea e ito threat- of List Red (Rodr´ Venezuelan animals ened sec- the the of in edition combined) categories ond risk (all fishes listed 13 Only are species. fish most for sta- unavailable structure are population genetic and on parameters, data demographic tus, basic example, For Orinoco basin. the in resources freshwater of man- management satisfy the hamper to gaps knowledge Various insufficient needs. agement currently is them, main- that tain processes ecological the and their distribution including basin, Orinoco the in habitats critical eety(00 nteCuaRvrbasin. River Caura the in (2000) recently conducted (AquaRAP) Program Aquatic Assessment the Rapid by illustrated as- is needs and management diversity sess map to appraisals biological rapid of feasibility The Venezuela. in implementation development and and await integrity) still protocols, biotic assessment rapid of quality indices habitat of species; metrics (indicator biotic freshwater as managing such and resources, evaluating for tools risk. sive of absence true V than rather on knowledge status of population Red lack the current in reflects The probably fishes List coast. Orinoco the of near representation sparse areas are populated rest the the densely and of basin from minority Orinoco the A from edition. is 1995 species 13 the in five from up aoyfihs a rae e aia o lentic- for habitat new created has fishes, ratory rosptnilyefcieadrltvl inexpen- relatively and effective potentially arious riwadpirt asadneeds and gaps priority and erview h raino as hl eattn omi- to devastating while dams, of creation The cetfi nesadn fdvriyhtpt and hotspots diversity of understanding Scientific nfihre aebe salse nreservoirs in established been have fisheries on ge n oa-urz 1999), Rojas-Suarez, and ıguez nfrtefis time first the for on npopulations on 149 Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 150 n etr u vnteeppltoshv enre- been have harvest- populations these withstand even to but better, seem produce ing eggs and of years 1-2 numbers and in large coporo mature The that abundance). species av- other stock reduced and (i.e., size overharvesting erage of signs show species first to the be to tend pavones and piscivo- catfishes rous Large fishers. subsistence by Shield and exploitation commercial Guayana heavy escaped the have of Amazonas and regions remote in pop- ulations Only ranges. their throughout fully overexploited been or have already stocks com- sportfish and major mercial the of Most Venezuela. throughout lem especially fishes, juveniles. and invertebrates den- aquatic high of support sities turn in that macrophytes, aquatic floating and emergent of growth dense support erally gen- and rivers whitewater of channels habitats Lentic within floodplains. habitats low-velocity in produc- tivity secondary and rivers primary high These show normally ecosystems. nutrients, whitewater and sediments in trap especially also nurs- Dams as areas. function ery that floodplains in sea- wetlands of sonal on creation and depend cues spawning for fishes floods flows. spawning annual low periodic, has or normally that Seasonal, during period flow dry increase annual the often and normal periods, during high-flow reaches downstream in flows to reduce tend Dams 1989). (Winemiller, pulses flood sonal sea- to response which in spawning of seasonal for most adapted are fishes, for consequences Venezuela serious in has regimes hydrological river Al- of migrations. teration fish of blockage and sedi- transport, of ment hydro- reduction cycles, natural nutrient and of regimes logic alteration including life, aquatic these regions. in extensive as not in usually is effects regions; siltation however, Shield same Amazonian/Guayana and the llanos has the Deforestation and webs. habitats food instream of of alteration and siltation desiccation, stream and and radiation solar erosion greater rivers, and in streams An- results the piedmont in Deforestation dean basin. Orinoco the life within aquatic on impacts most far-reaching the and widespread perhaps has through- Deforestation exist country. now to which the added of out be most threats can of tilapias, list as this introduction such The species, 1996). exotic al., of et Winemiller in (summa- rized pollution and defor- overfishing, threats: dams, major estation, four with associated are basin sdsusdaoe vrsigi eiu prob- serious a is overfishing above, discussed As and rivers on impacts multiple have Dams Orinoco the in fishes for priorities Management Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ilt opeeyetraeetr ouain from se- populations w entire of extirpate completely induction to tial Thus, season. v rainy spawn the to marshes during flooded seasonally refu- into dry-season move these gia from fishes adult Normally, into for habitat waste dry-season ag organic re- critical liquid provide llanos that of western streams amounts the large in Sugar lease Venezuela. plants in processing hypoxia streams cane aquatic and rivers severe several in sewage in results from waste agriculture Organic (Nico and organisms 1994). aquatic Taphorn, other and and acute miners, fishes particularly gold to a threat by poses exploited contamination regions mercury In rivers. into elements and chemicals cause toxic large gold introduce Shield, and and siltation Guayana iron, bauxite, the for im- In operations negative mining stocks. severe fish have on which pacts of most sources, e black- unproductive in w populations Fish (Winemiller b). pulse 1996a, flood annual the from derived dynam- ics ecological and changes habitat in with decline concert catastrophic and growth pressure, explosive expe- rience fishing normally populations to these resilient because probably relatively llanos be western to the migrating seem in every populations virtually Fish the catch individual. across can stretched channel gillnets river where areas in duced se,adfisheries and habitats, fishes, for potential and trends Future rnc i et hc pn h ttso Gu´ the of states Second, the spans rangeland. which belt, and oil Orinoco land cre- to agricultural forests of ate clearcutting and burning and ing), min- peat and networks, wetlands, drainage construction, of road channeling of development (dredging, the by infrastructures degraded be likely will delta notice. F special merit the future the in to development rapid economic by migrations new threatened potentially zones massive seeking Three opportunities. north- people to of large led region the Guayana has in cities country. opportunities the ern of for decline priority development The high a fore V potto eg,pav´ (e.g., xploitation r yoi uigtedysao a h poten- the has season dry the during hypoxia ere rt qai niomnsi h creypopulated scarcely the in environments aquatic irst, nzealvsi oet,adti eini there- is region this and poverty, in lives enezuela atersheds. to sensitive more be to appear rivers ater P oeta afo h ouaini southern in population the of half than More etdvriyo se Wnmle ta. 1996). al., et (Winemiller fishes of diversity reat luini eeul eie rmseveral from derives Venezuela in ollution ndsusdabove). discussed on arico, Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 ieypooefihcluewielseigrs to risk lessening environment. while the culture effec- fish could promote producers of tively scale cultivation small by Extensive species culture. these fish and advice on provide guidance to programs extension of ab- sence and fingerlings quality high of unavailability the culti- centers in v research ventures Commercial strong funding. of steady with absence partly the promotion, of and because research of decades despite the in changes collapses irreversible, stock fishery. possibly prevent other, help and can regulations fish- of ery enforcement Timely if opportunity. quickly the sizes habi- given population low lost from recover of recover and can typical tat drainage seasons Orinoco dry and entire wet the the the of to pulse adapted annual exploited fishes lightly Furthermore, only unexploited. are or basin Orinoco sec- the many of because tors hope for decades is, reason There last some conditions. however, the these con- under in worsen but seen likely gradual will harvests fish The in capture limits. decline and tinual size sizes, legal mesh the illegal below season, with of out nets operate use fishers result, in- a been As have Barrancas, law effective. fishery and the implement Cabruta, to Apure, attempts de as such Fernando centers San fishing major Venezuela’s Near of fisheries. future inland bleak a for bodes law the en- force to will institutional of lack the legislation, fishery for need the reduce may dredging. delta. vessels the low-draft in of intrusion Use groundwater saltwater promote affect and patterns, flow, modify siltation sediments, and the erosion in stored habitats, pollutants floodplain release and aquatic degrade may to plans addition such sectors, In unaltered rivers. in development Apure encouraging the and vessels, ocean- going accepts which Orinoco, the navi- both improve along gation to planned is the dredging Additionally, to waters Caura’s the Caron´ divert to high of or region biodiversity, the pristine in a River, dam Caura hydroelectric south-eastern a building for plans nally, Fi- alterations. hydrological and spills, soils, of oil salinization of risk the pose activities Extractive demand oil. worldwide for increasing exploitation, the scale given large especially to The subject soon bitumen. be and may oil belt extra-heavy of reserves huge Anzo´ to fccaaadrdtlpaaehnee by hindered are tilapia red and cachama of ation F modernize to efforts successful recent of spite In s utr nVnzeai tl underdeveloped still is Venezuela in culture ish tgi oaa,adDlaAauo contains Amacuro, Delta and Monagas, ategui, ıR iv r aebe ne td o ogtime. long a for study under been have er, Rodr´ ge ta./AutcEoytmHat n aaeet1 20)140–152 (2007) 10 Management and Health Ecosystem Aquatic / al. et ıguez ei,W .J. aitn .K,Ls,M . Rodr´ A., M. Lasi, K., S. Hamilton, Jr., M. W. Lewis, Rivers 1995. III, F. J. Saunders, K., S. Hamilton, Jr., M. W. Lewis, A., J. Maldonado-O., S., J. Usma, I., J. Mojica, A., C. Lasso, Lasso- C., DoNascimiento, D., Taphorn, D., Lew, A., C. Lasso, P´ A., Machado-Allison, C., Lasso, river tropical of Structure 2002. O., K. Winemiller, B., D. Jepsen, 2004. C., D. Taphorn, O. K. Winemiller, J., D. Hoeinghaus, Winemiller, A., D. Arrington, A., C. Layman, J., D. Hoeinghaus, Aquaculture Venezuela. in culture Cachama 1990. G., Ginelly, Mor- 1991. G., W. Saul, A., Machado-Allison, B., Chernoff, 1998. O., K. Winemiller, C., D. Taphorn, A., Duque, Barbarino segrega- Dietary 2003. O., K. Winemiller, A., Duque, Barbarino Com- 2005. A., C. Layman, O., K. Winemiller, A., D. Arrington, in changeover Diel 2003. O., K. Winemiller, A., D. Arrington, References .A,Sudr,J .II 00 clgcldtriimon 681–692. 50, determinism BioScience Ecological floodplain. 2000. Orinoco III, the F. J. Saunders, A., M. California. Berkeley, Press, California of University 256. G. Cummins, W. K. Cushings, C. In: America. South Northern of In sub-basin. by 95–158. distribution 5, and Colombiana Biota list Spanish). Species I: Part basin. y P Su´ R., Royero, A., Allison, Lasso- F., Provenzano, Alcal´ C., D. Taphorn, C., DoNascimiento, 105–195. 159–160, Naturales Ciencias Fundaci´ de la and Salle de La list Memoria Spanish). Species In I. basin. by Part distribution Venezuela. of biodiversity ological distribuci´ y especies de ictiol´ diversidad Alcal´ 109–129. 133–134, Salle Sociedad La Naturales la Ciencias de de Memorias Spanish). In basins. neighbouring Caron´ (Upper Sa- bana Gran the of fishes of zoogeography the on (Considerations Caron´ zoogeogr´ ciones 46–55. 96, Oikos ratios. isotope stable by revealed webs food R´ V the of gradient Andean floodplain the piedmont–Llanos along assemblages fish in change Compositional 126. of Movement V 2003. O., K. 52–65. 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A., Machado-Allison, F., Provenzano, O., a, )Vnzea u eainscnlscecsvecinas cuencas las con relaciones sus y Venezuela, ı) nprsbuna Fse fteOiooRiver Orinoco the of (Fishes subcuencas por on gc otnna eVnzea at .Lista I. Parte Venezuela. de continental ogica fia elspcsd aGa aaa(Alto Sabana Gran la de peces los de aficas )Vnzea n hi eainhp with relationships their and Venezuela, ı) ie n temEcosystems Stream and River rciou mariae Prochilodus nprcecs(otnna ichthy- (Continental cuencas por on oOioo at :lsad especies de lista I: Parte Orinoco. ıo rz . reaLr,A,2004b. A., Ortega-Lara, C., arez, suz . uo . Machado- M., Lugo, L., asquez, Cichla rz . 91 Considera- 1991. H., erez, p.(ihia)i a in (Cichlidae) spp. eoiu brunneus Leporinus (Characiformes, oPortuguesa, ıo , p 219– pp. ıguez, 151 on Downloaded By: [Canadian Research Knowledge Network] At: 16:43 15 June 2007 udeg .G,Lws .M r,Sudr,J .II Mago-Leccia, III, F. J. Saunders, Jr., W. M. Lewis, G., J. 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