The biodiversity of many Brazilian rivers is seriously threatened by industrial and municipal pollution, and Rio Paraiba do Sul, located between two major industrial centers is one example of this situation. A survey of the fish assemblage was conducted from October 1998 to September 1999 and the data were used to develop an index of biotic integrity (IBI). We sampled three zones in bracketing a large urban-industrial complex to evaluate water quality changes and the usefulness of the IBI as a monitoring tool. Water quality was classified as poor upstream of the effluent discharges, very poor near the discharges, and poor-fair downstream of the discharges, with this latter situation revealing the current biological capacity of the river. Physical and chemical habitat characteristics were also measured at each site to construct an independent environmental index to validate the IBI. The habitat and IBI indices were highly correlated, suggesting this IBI would be applicable to other large rivers in southeast Brazil.
Rineloricaria daraha, new species, is described from the rio Daraá, tributary of rio Negro, northwestern Amazonas State, Brazil. The new species is diagnosed by having seven branched pectoral-fin rays, finger-like papillae on the lower lip, a large multi-angular preanal plate, and at least four quadrangular plates of variable size surrounding the preanal plate. The new species is known only from rio Daraá and its waterfalls.Rineloricaria daraha, espécie nova, é descrita do rio Daraá, um afluente do rio Negro, noroeste do Estado do Amazonas, Brasil. A nova espécie pode ser diagnosticada por apresentar sete raios ramificados na nadadeira peitoral, lábios inferiores com papilas digitiformes, uma grande placa pré-anal multi-angular e, pelo menos, quatro placas de diferentes tamanhos circundando a placa pré-anal. A nova espécie é conhecida apenas do rio Daraá e suas cachoeiras.
ABSTRACT. Spatial Variation in Fish Assemblage in the Paraíba do Sul River (Barra Mansa, Barra do Piraí), Rio de Janeiro, Brazil. The Paraíba do Sul is a major running water system in southeastern Brazi I (22°24 ' -22°26 ' S; 43°43' _44° 16' W), draining one of the most important industrial regions in the country. Because of its location, it has suftered a large amount 01' alteration due to discharges of urban and industrial eftluents with direct innuence in the ichthyotàuna. The aim ofthis study is to up-to-date information on fish assemblage structure and its variation in the vic inity 01' a major industrial effluent outfall at Volta Redonda industrial complex. A standardized fishing sampling program, using seines, casting nets, gill nets and net trays, was carried out from October 1997 to September 1999, at six sites in three zones of the river (upstream, nearby and downstream lhe industrial complex), aiming to compare variation in fish assemblage due to anthropogenic alteration. Fifty-two species in 13 families were identified in the total of 7286 fish specimens. Characidae was the most divel'se family contributing with 28,85% to total number of species, followed by Cichlidae (17,31 %). Overall 15,38% ofthe species were introduced from other watershed systems, four exotic cichl ids (genera Oreochromis Günther, 1862 and Tilapia A. Smith, 1840) and three aloctone (CieMa oeellaris Bloch & Schneider, 1801 , Hyphessobrieol1 eallis/us (Boulenger, 1900) e Me/yl1l1is maeula/us (Kner, 1860)). Lebistes retielllatlls (Peters, 1859) was the most abundant tish species contributing to 39,7% of the total number of fish, followed by Geophagus brasiliellsis (Quoy & Gaim ard, 1824) amounting to 27,4%. Fish abundance was higher in the industrial zone, but only a few very dominant species were captured, while the upstream zone showed the most even community. Species replacement tolerance along the altel'ations gradient in the three zone seems to be a strategy to use the limited resources in the area. KEY WORDS. Rivers, tish taxocenose, pollution, ichthyofauna, fish ecology o rio Paraíba do Sul é um ecossistema de grande importância, pois suas águas são utilizadas, tanto para consumo doméstico e industrial, como para a produção de energia, suprindo cerca de 90% da demanda do município do Rio de Janeiro e arredores (SILVEIRA el a!. 1979;BARROSO 1989). Apesar desta importância, poucas são as informações atualizadas sobre a biota, tais como as assembléias de peixes, organismos estes importantes como indi cadores da qualidade ambien tal do rio. O trecho mais utilizado, e portanto mais alterado do rio, situa-se entre Barra Mansa e Barra do Piraí, onde o rio atravessa o complexo industrial
Este trabalho teve como objetivo avaliar o ciclo reprodutivo do bagre de água doce Parauchenipterus striatulus, na represa de Ribeirão das Lajes, Rio de Janeiro. Foram descritos aspectos morfológicos dos estádios de maturação gonadal bem como variações no índice gonadossomático, relação peso:comprimento, fator de condição e condição gonadal. A amostragem dos peixes foi feita bimestralmente entre abril de 1996 e maio de 1997 com o uso de redes de espera de 100m de comprimento, 4m de altura e com malha entre 25 e 65mm de distância entrenós. Os 339 indivíduos capturados ao longo do período de amostragem corresponderam a 40% do total de peixes. Cinco estádios de maturação gonadal foram determinados por meio de análise macroscópica para ambos os sexos: imaturo, maturação I, maturação II, maduro, desovado (fêmeas) e esvaziado (machos). O índice gonadossomático foi mais elevado entre outubro e março para ambos os sexos, sugerindo amplo período de desova enquanto o fator de condição atingiu seu máximo entre fevereiro e junho, mostrando uma relação inversa entre essas duas características. A relação peso-comprimento para machos foi de W= 0,0095L3,0862 e fêmeas de W= 0,0116L3,0126, não tendo sido encontradas diferenças significativas entre os coeficientes de alometria para ambos os sexos.
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