Infection levels ofAustrodiplostomum compactum(Digenea, Diplostomidae) metacercariae inPlagioscion squamosissimus(Teleostei, Sciaenidae) from the Nova Avanhandava reservoir, São Paulo State, Brazil

Abstract

This study was aimed at evaluating the infection levels of Austrodiplostomum compactum metacercariae in 378 specimens of Plagioscion squamosissimus ('corvina' or 'pescada branca') from the Nova Avanhandava reservoir, low Tietê River, São Paulo State, Brazil. High prevalence, mean intensity of infection and abundance were observed in P. squamosissimus during most of the study, with the exception of March 2004. The relative condition factor (Kn) did not differ between parasitized and non-parasitized fish. A statistically significant positive correlation was observed between host standard length and intensity of infection. The analysis of biotic and abiotic variables showed that no abiotic variable correlated with parasitic infection levels. Moreover, P. squamosissimus status was demonstrated to be unaffected by A. compactum metacercariae infection.

Austrodiplostomum compactum (Lutz, 1928) (Digenea, Diplostomidae) in the eyes of fishes from Paraná river, Brazil

“…Machado et al (2005) registered a positive correlation between C. britskii size and the prevalence of A. compactum and attributed this fact to the possibility of larger fish being easier targets for cercariae. The parasite load in P. squamosissimus increased with fish length, as reported by Paes et al (2010). These authors also attributed the cumulative process to a greater body surface available for cercariae infection.…”

“…The latter species achieved indexes up to 100% (Table 6). Plagioscion squamosissimus, also with mean high infection intensity, was the most parasitized fish species reported not only in current study but also in Santos et al (2002) Although no significant difference in mean intensity and abundance of metacercariae throughout the seasons has been reported in current research, P. squamosissimus examined in spring and autumn had the highest parasitic load when compared to findings by Paes et al (2010) in the same fish species in the Nova Avanhandava reservoir.…”

“…In contrast, analyzing P. squamosissimus from Nova Avanhandava reservoir in the state of São Paulo, Brazil, Paes et al (2010) did not report any influence either of aquatic parameters or of rainfall on the parasitic fauna. Since transmission is a major determinant of parasite fitness, perhaps other factors, such as local host population dynamics, fish feeding habits, strategies in cercarial release from first intermediate hosts and also the type of fresh water environments (lotic or lentic environment), would be primarily influencing success in parasite transmission.…”

“…Metacercariae of Diplostomum and Austrodiplostomum are frequently reported parasitizing freshwater fishes which are the second intermediate hosts in the parasite's life-cycle (RINTAMAKI-KINNUNEN et al, 2004;SEPPALA et al, 2004). Whereas the adult stage inhabits the digestive tract of piscivore birds, its larval cercariae stage may be found in aquatic mollusks.…”

“…Metacercariae have been found in Plagioscion squamosissimus Heckel, 1840(KOHN et al, 1995MACHADO et al, 2005;MARTINS et al, 2002;PAES et al, 2003PAES et al, , 2010SANTOS et al, 2002;TAKEMOTO et al, 2009), Hypostomus regani Ihering, 1905(TAKEMOTO et al, 2009YAMADA et al, 2008;ZICA et al, 2009), Cichla monoculus Spix and Agassiz, 1831 (MACHADO et al, 2000(MACHADO et al, , 2005TAKEMOTO et al, 2009), Cichla ocellaris Bloch andSchneider, 1801 (MACHADO et al, 2005;SANTOS et al, 2002), Pimelodus maculatus Lacepéde, 1803 (BRASIL-SATO;BACHMANN et al, 2007), Hoplias malabaricus Bloch, 1794 (MACHADO et al, 2005;TAKEMOTO et al, 2009), Satanoperca pappaterra Heckel, 1840(MACHADO et al, Acta Scientiarum. Biological Sciences Maringá, v. 34, n. 2, p. 225-231, Apr.-June, 2012 2005; TAKEMOTO et al, 2009), Geophagus brasiliensis Quoy andGaimard, 1824 (AZEVEDO et al, 2006;NOVAES et al, 2006) and Crenicichla britskii Kullander, 1982(MACHADO et al, 2005TAKEMOTO et al, 2009), Serrasalmus maculatus Kner, 1858, Schizodon borellii Boulenger, 1900and Auchenipterus osteomystax Mirando Ribeiro, 1918(TAKEMOTO et al, 2009YAMADA et al, 2008), Conorhynchos conirostris Valenciennes, 1840 (BRASIL-SATO;SANTOS, 2005), Cyphocharax Gilbert Quoy and Gaimard, 1824 (ABDAL...…”