Diversity of parasites of fish from the Upper Paraná River floodplain, Brazil.

The aim of the present study was to provide a current survey of the species of parasites found in the Upper Paraná River floodplain, as well as to investigate which strategies and mechanisms used by parasites, are favored and which environmental factors influence the parasite community in the studied environments. During a seven-year period from February 2000 to September 2007, 3,768 fish belonging to 72 species were collected and analyzed for the purpose of studying the parasite fauna. A total of 337 species of parasites were reported, including 12 new descriptions: one myxosporid, Henneguya paranaensis Eiras, Pavanelli and Takemoto, 2004; eight monogeneans, Kritskyia annakohnae Boeger, Tanaka and Pavanelli, 2001; Kritskyia boegeri Takemoto, Lizama and Pavanelli, 2002; Kritskyia eirasi Guidelli, Takemoto and Pavanelli, 2003; Demidospermus labrosi França, Isaac, Pavanelli and Takemoto, 2003; Demidospermus mandi França, Isaac, Pavanelli and Takemoto, 2003; Pseudovancleaveus paranaensis França, Isaac, Pavanelli and Takemoto, 2003; Tereancistrum curimba Lizama, Takemoto and Pavanelli, 2004 and Tereancistrum toksonum Lizama, Takemoto and Pavanelli, 2004; two digeneans, Sanguinicola platyrhynchi Guidelli, Isaac and Pavanelli, 2002 and Dadayius pacupeva Lacerda, Takemoto and Pavanelli, 2003 and one cestode, Nomimoscolex pertierrae Chambrier, Takemoto and Pavanelli, 2005. In addition, several other species were reported for the first time in new hosts or in the floodplain. Monogeneans presented the highest number of species, followed by digeneans. The infection site with the highest species richness was the intestine, with 127 species.

Diversity of parasites of fish from the Upper Paraná River floodplain, Brazil / Diversidade dos parasitos de peixes da planície de inundação do Alto Rio Paraná, Brasil

The aim of the present study was to provide a current survey of the species of parasites found in the Upper Paraná River floodplain, as well as to investigate which strategies and mechanisms used by parasites, are favored and which environmental factors influence the parasite community in the studied environments. During a seven-year period from February 2000 to September 2007, 3,768 fish belonging to 72 species were collected and analyzed for the purpose of studying the parasite fauna. A total of 337 species of parasites were reported, including 12 new descriptions: one myxosporid, Henneguya paranaensis Eiras, Pavanelli and Takemoto, 2004; eight monogeneans, Kritskyia annakohnae Boeger, Tanaka and Pavanelli, 2001; Kritskyia boegeri Takemoto, Lizama and Pavanelli, 2002; Kritskyia eirasi Guidelli, Takemoto and Pavanelli, 2003; Demidospermus labrosi França, Isaac, Pavanelli and Takemoto, 2003; Demidospermus mandi França, Isaac, Pavanelli and Takemoto, 2003; Pseudovancleaveus paranaensis França, Isaac, Pavanelli and Takemoto, 2003; Tereancistrum curimba Lizama, Takemoto and Pavanelli, 2004 and Tereancistrum toksonum Lizama, Takemoto and Pavanelli, 2004; two digeneans, Sanguinicola platyrhynchi Guidelli, Isaac and Pavanelli, 2002 and Dadayius pacupeva Lacerda, Takemoto and Pavanelli, 2003 and one cestode, Nomimoscolex pertierrae Chambrier, Takemoto and Pavanelli, 2005. In addition, several other species were reported for the first time in new hosts or in the floodplain. Monogeneans presented the highest number of species, followed by digeneans. The infection site with the highest species richness was the intestine, with 127 species.

O objetivo do presente trabalho foi realizar um novo levantamento das espécies de parasitos encontradas na planície de inundação do Alto Rio Paraná, bem como investigar quais estratégias e mecanismos utilizados pelos parasitos são mais favorecidos e quais fatores ambientais estão influenciando a comunidade parasitária nos ambientes estudados. Durante o período de fevereiro de 2000 a setembro de 2007, 3.768 espécimes de peixes pertencentes a 72 espécies foram coletados e analisados, visando o estudo da fauna parasitária. Até o momento foram registradas, 337 espécies de parasitos, sendo 12 novas espécies: uma de mixosporídeo, Henneguya paranaensis Eiras, Pavanelli e Takemoto, 2004; oito de monogenéticos, Kritskyia annakohnae Boeger, Tanaka e Pavanelli, 2001; Kritskyia boegeri Takemoto, Lizama e Pavanelli, 2002; Kritskyia eirasi Guidelli, Takemoto e Pavanelli, 2003; Demidospermus labrosi França, Isaac, Pavanelli e Takemoto, 2003; Demidospermus mandi França, Isaac, Pavanelli e Takemoto, 2003; Pseudovancleaveus paranaensis França, Isaac, Pavanelli e Takemoto, 2003; Tereancistrum curimba Lizama, Takemoto e Pavanelli, 2004 e Tereancistrum toksonum Lizama, Takemoto e Pavanelli, 2004; duas de digenéticos, Sanguinicola platyrhynchi Guidelli, Isaac e Pavanelli, 2002 e Dadayius pacupeva Lacerda, Takemoto e Pavanelli, 2003 e uma de cestóide, Nomimoscolex pertierrae Chambrier, Takemoto e Pavanelli, 2005. Além dessas novas espécies, várias outras foram registradas pela primeira vez em novos hospedeiros ou na planície. O grupo dos monogenéticos foi o que apresentou maior número de espécies encontradas, seguido pelos digenéticos. O intestino foi o sítio de infecção que apresentou a maior riqueza, com 127 espécies.

Host population density as the major determinant of endoparasite species richness in floodplain fishes of the upper Paraná River, Brazil.

A comparative analysis of parasite species richness was performed across 53 species of fish from the floodplain of the upper Paraná River, Brazil. Values of catch per unit effort, CPUE (number of individuals of a given fish species captured per 1000 m(2) of net during 24 h) were used as a rough measure of population density for each fish species in order to test its influence on endoparasite species richness. The effects of several other host traits (body size, social behaviour, reproductive behaviour, spawning type, trophic category, feeding habits, relative position in the food web, preference for certain habitats and whether the fish species are native or exotic) on metazoan endoparasite species richness were also evaluated. The CPUE was the sole significant predictor of parasite species richness, whether controlling for the confounding influences of host phylogeny and sampling effort or not. The results suggest that in the floodplain of the upper Paraná River (with homogeneous physical characteristics and occurrence of many flood pulses), population density of different host species might be the major determinant of their parasite species richness.