MENEZES, M.S. A comparative analysis of biotic indices that use macroinvertebrates to assess water quality in a coastal river of Paraná state, southern Brazil. Biota Neotrop. 11(4): http://www. biotaneotropica.org.br/v11n4/en/abstract?article+bn00411042011.Abstract: Biotic indices to monitor water quality are helpful tools for evaluating the health of rivers and lakes. In Brazil water samples are mainly analyzed using physical and chemical attributes, because most biotic indices were developed in other countries and their effective application to Brazilian ecosystems requires significant research. This study compared four biotic indices commonly used to evaluate water quality via benthic macroinvertebrates in order to determine which index best reflects ecosystem health in a coastal river in Brazil's Paraná state. We also analyzed functional feeding groups. The indices studied were: 1) EPT (percent of Ephemeroptera, Plecoptera and Trichoptera); 2) BMWP' (Biological Monitoring Work Party System); 3) BMWP'-ASPT (Average Score per Taxon); and 4) HFBI (Hilsenhoff Family Biotic Index). All indices were calculated from five samples collected from April 2005 to April 2006 at two stations on the coastal do Pinto River. The river's headwaters are inside a protected area but impacts increase downriver (e.g., towns, cattle grazing, tourism). The HFBI index did the poorest job of reflecting water quality. No one index performed better than the others, and all indices yielded water quality scores that did not accurately reflect macroinvertebrate community structure because all of them had differences between ordination scores and the structure of assemblage. The functional feeding groups protocol classified the lower stretch of the river as disturbed due to human impacts, suggesting that this method is a good one to evaluate health in environments.

O presente trabalho visou compreender a estrutura da comunidade de macroinvertebrados bentônicos da bacia do rio Ribeirão no município de Paranaguá (Pr), com coletas realizadas no período de outubro/2002 e fevereiro/2003 durante as estações de primavera e verão, respectivamente. Chironomidae mostrou-se predominante na maioria dos substratos amostrados, com exceção de Vegetação Marginal onde Palaemonidae foi dominante. A ocorrência de fortes chuvas no período da coleta de verão levou a um aumento da diversidade devido a quebra de dominância dos grupos majoritários. ABSTRACT To understand the structure of the community of benthonic macroinvertebrates of the basin of the Ribeirão river in the city of Paranaguá (PR). The samplings were carried through from October/2002 to February/2003, during the Spring and Summer, respectively. Chironomidae predominante in the majority of substrata, except in the Marginal Vegetation, where Palaemonidae predominates. The occurrence of strong rains in the period of the Summer collection possibly contributed to the increase of the diversity due the decrease of the dominance in the majority of groups in the samples collected in the period from October/ 2002 to February/2003. RÉSUMÉ Le présent travail visait etablar la structure de la population de macroinvértebré bentoniques de la bassin du riviere Ribeirão dans les ville de Paranaguá (PR), avec collectes ayant eté realisé dans les période de octobre de 2002 et fevrier de 2003 au cours des la saison de la printemps et été respetivement. Chironomidae montrait predominante dans les majorité des types ayant été echantillonné, avec la exception de la végétation marginal, où Palaemonidae etait dominant. L’ocurrance de fort pluie dans le période de la collecte d’été portait l’une elévation de la diversité dû la casse de la predominance des groupes majoritaires.