Metazoan endoparasites diversity of Pseudoplatystoma corruscans (Siluriformes: Pimelodidae) as an indicator of environmental alterations on a tropical aquatic system

Abstract

The aim of the present study was to detect the alterations of Pseudoplatystoma corruscans parasite infracommunity structure, after the construction of the Porto Primavera dam on the high Paraná River floodplain. The execution of this research was based on 119 host specimens collected between March 2011 and September 2012, and the results were compared to studies performed on periods before the reservoir's construction, when 110 fishes were collected between March 1992 and February 1993. Five parasite species still remain on the environment, despite the environmental modifications: Choanoscolex abscissus, Spasskyelina spinulifera, Nomimoscolex pertierrae, Harriscolex kaparari and Contracaecum sp 2. The Berger-Parker dominance index, calculated to the parasite fauna of 1992, did not show the dominance of any species, while, on the present days, this same index accused the dominance of Nomimoscolex pertierrae (49%) and Choanoscolex abscissus (50%). The present study reports the disappearance of Megathylacus travassosi, Contracaecum sp. 1, Contracaecum sp. 3, Procamallanus (Spirocamallanus) sp. and Cucullanus pseudoplatystomae, suggesting the possibility of a local extinction or a host switch of these species. It has also been registered an Acanthocephala specimen, a genus not observed on this host yet. The results here presented show that the antropic influences on natural systems alter the environmental conditions, what is reflected on the richness and diversity parasite levels.

<b>Fish parasite diversity in the Amambai river, State Mato Grosso do Sul, Brazil

“…The cestode Choanoscolex abscisus was observed to be dominant in P. corruscans. According to Rego (2002), proteocephalid cestodes are the major helminth found in this species and have been reported in the genus Pseudoplatystoma by Rego (2002), Campos, Fonseca, Takemoto, and Moraes (2008) and Ribeiro, Lizama, and Takemoto (2014), among others. The presence of adult cestodes in P. corruscans indicates that these hosts are part of the top level of the food chain, where they feed on fish, which are used as intermediate hosts in the life cycle of proteocephalids, and, in general, support parasitism by adult cestodes because they only remove the food necessary for their survival (Pavanelli et al, 2008).…”

Annotated checklist of fish cestodes from South America

“… Pseudoplatystoma corruscans ( Actinopterygii : Pimelodidae ); freshwater; intestine; adult; Paraná and São Francisco River basins; Brazil, Paraguay ( Riggenbach 1895 , 1896b ; La Rue 1911 , 1914 ; Rego and Gibson 1989 ; Rego 1990 , 2002 ; Pavanelli and Machado 1991 ; Machado et al 1994 , 1995 , 1996 ; Mariaux 1998 ; de Chambrier and Vaucher 1999 ; Zehnder and Mariaux 1999 ; Ceccarelli et al 2006 ; Kohn et al 2011 ; Ribeiro and Takemoto 2014 ; Ribeiro et al 2014 ).…”

“… Pseudoplatystoma corruscans ( Actinopterygii : Pimelodidae ); freshwater; intestine; adult; Paraná River basin; Argentina, Brazil, Paraguay ( Rego 1990 , 2002 ; Pavanelli and Machado 1991 ; Machado et al 1994 , 1995 , 1996 ; de Chambrier and Vaucher 1999 ; Santos et al 2003 ; Ceccarrelli et al 2006 ; Kohn et al 2011 ; Ribeiro et al 2014 ; de Chambrier et al 2015b ).…”

“… Pseudoplatystoma corruscans ( Actinopterygii : Pimelodidae ); freshwater; intestine; adult; Paraná river basin; Brazil ( Pavanelli and Rego 1992 ; de Chambrier et al 2006b ; Ribeiro and Takemoto 2014 ; Ribeiro et al 2014 ).…”