04999naa a2200505 a 450000100080000000500110000800800410001902000180006010000190007824501540009726000090025130000130026049000770027350002430035052031920059365000110378565000090379665000130380565000130381865000280383165000180385965000330387765000120391065000100392265000130393265300110394565300170395665300170397365300170399065300160400765300140402365300150403770000180405270000240407070000160409470000160411070000190412670000170414570000190416270000200418170000150420170000180421670000160423477302430425018043552000-11-30       2000    bl uuuu     u00u1 u    #d  a1-881173-35-61 aWILLINK, P. W.  aFishes of the Rios Negro, Negrinho, Taboco, Aquidauana, Taquari, and Miranda, Pantanal, Brasilbdiversity, distribution, critical habitats and value.  c2000  ap.63-81.  a(Conservation International. RAP Bulletin of Biological Assessment, 18).  aTitulo em portugues: Diversidade, distribuicao, e habitats criticos dos peixes dos rios: Negro, Negrinho, Taboco, Taquari e Miranda, e sua importancia para conservacao e desenvolvimento sustentavel do Pantanal, Mato Grosso do Sul, Brasil.  aFish were sampled from 77 localiteis in the Rio Negro, Upper Rio Taquari, Upper Rio Aquidauana and Upper Rio Miranda drainages. A total of 193 fish species were collected. Of these fish species, 90 (47%) were Characiformes, 72 (37%) were Siluriformes, 15 (8%) were Perciformes and 11(6%) were Gymnotiformes. Cyprinodontiformes (2 species, 1%), Beloniformes (1 species, 0.5%), Synbranchiformes (1 species, 0.5%) and Pleuronectiformes (1 species, 0.5%) were also represented. The family with the most species was Characidae (67 species, 35%), followed by Loricariidae (29 species, 15%) and Cichlidae (15 species, 8%). Of these 193 species, 36 (19%) are believed to be new to science. The specimens collected are believed to be a reasonable representation of the area's ichthyofauna, although additional species are likely to be found in the headwaters and large-bodied fishes were probably undersampled. Endemicity was higher in the headwaters than in the floodplain, probably because of the relatively greater difficulty in dispersing from one headwater drainage to another. The parts of streams located above waterfalls are less productive and diversified than those below. Otherwise, two types of situations were noticed in the headwaters. 1) Relatively unmodified streams with a large number of ecological niches and a high biodiversity. Biodiversity and abundance were particularly high in the clear water limestone areas of the Rio Miranda drainage in Bonito and adjacent areas. 2) Streams heavily impacted by pollution, siltation, and/or deforestation. These streams had few microhabitats and were inhabited mainly by opportunistic species. Biodiversity in the Negro drainage (67 in the Upper Negro to 113 in the Lower Negro, 26 in the Upper Taboco to 77 in the Middle Taboco). This increase in biodiversity is correlated with increases in river size and habitat complexity, with hatitat complexity correlated with the degree of seasonal flooding. Some taxa were collected throughout the drainage, whereas others were collected only in restricted areas. Many juvenile fishes were collected in the bracos mortos (a lateral arm of a river where the upriver channel has been closed), swamps and baias (seasonal lakes or ponds generally isolated from the river system except in times of flooding), emphasizing the importance of these as nursery areas. Terrestrial input of nutrients from riparina vegetation and as a consequence of the seasonal flooding is believed to be critical to the aquatic food chains which support the Pantanal fishes. The majority of an individual's annual growth occurs during the period of high water. Seasonal floods also serve as a cue for many fishes to reproduce, and help to maintain the habitat complexity of the region by rejuvenating the swamps, bracos mortos and baias. These areas, now rich in nutrients function as the nursery areas for fishes. Deforestation is a severe threat because in removes the vegetation from alongside the rivers, decreasing allochthonous input and increasing sedimentation. Disruption of the seasonal flooding (e.g., from local dredging or the Hidrovia Paraguai-Parana) would be catastrophic to the fishes of the Pantanal.  aBrazil  afish  aPantanal  aresearch  asustainable development  aConservação  aDesenvolvimento Sustentável  aHabitat  aPeixe  aPesquisa  aBrasil  aConservation  aDistribuicao  aDistribution  aDiversidade  aDiversity  aIctiofauna1 aFROEHLICH, O.1 aMACHADO-ALLISON, A.1 aMENESES, N.1 aOYAKAWA, O.1 aCATELLA, A. C.1 aCHERNOFF, B.1 aLIMA, F. C. T.1 aTOLEDO-PIZA, M.1 aORTEGA, H.1 aZANATA, A. M.1 aBARRIGA, R.  tIn: WILLINK, P.W.; CHERNOFF, B.; ALONSO, L.E.; MONTAMBAULT, J.R.; LOURIVAL, R., ed. A Biological assessment of the aquatic ecosystem of the Pantanal, Mato Grosso do Sul, Brasil. Washington, DC: Conservation International, 2000. capitulo 6