Ecological aspects of nematode parasites of introduced salmonids from Valdivia river basin, Chile

Abstract

Between 1986 and 1987, 666 fishes distributed among the following species introduced in Chile, and from different sectors of the Valdivia river basin (39 degrees 30'-40 degrees 00'S, 73 degrees 30'-71 degrees 45'W), were examined: 348 Salmo trutta, 242 Salmo gairdneri, 24 Cyprinus carpio and 52 Gambusia affinis holbrooki. The presence of Camallanus corderoi and Contracaecum sp. in S. gairdneri and of C. corderoi in S. trutta is recorded in Chile for the first time. Cyprinus carpio and G. a. holbrooki did not present infections by nematodes. The prevalence and mean intensity of the infections by nematodes presented significant differences among some sectors of the Valdivia river basin. In general, the prevalence and intensity of the infections by C. corderoi were greater than those by Contracaecum sp. The infections in S. gairdneri were higher than in S. trutta. The sex of the hosts had no influence on the prevalence and intensity of the infections by both nematodes. The length of the hosts did have an influence, except in the case of the infections by Contracaecum sp. in S. gairdneri. The infrapopulations of both nematode species showed over-dispersion in most cases. The diet of the examined salmonids suggests that they would become infected principally through the consumption of autochthonous fishes.

Infections by Helminth Parasites in "Puyenes", Galaxias maculatus (Galaxiidae, Salmoniformes), from Southern Argentina with special reference to Tylodelphys barilochensis (Digenea, Platyhelminthes)

“…This mechanism has been proposed for G. maculatus and salmonids for Contracaecum sp. and C. corderoi, in Chile (Torres et al 1991). According to our results, the role of G. maculatus population in transmission of parasites to the salmo-sites and contradicts the argument of salmonids as paratenic hosts.…”

Helminths ofMilvago chimango temucoensis(Aves: Falconiformes) from Los Ríos Region, Chile: New Records for Neotropical Raptors

“…There are several reports of Contracaecum spp. L3 in fi shes from Chile, Argentina and Malvinas (Torres et al, 1991a;Brickle & MacKenzie, 2007;Alarcos & Etchegoin, 2010;Carballo et al, 2011;Fernandez et al, 2012). The predation, viscera intake or spreading of these fi shes by the fi shermen are contributing to the fi sh-eating birds infection (Torres et al, 1991b).…”

Camallanus maculatus n. sp. (Nematoda: Camallanidae) in an ornamental fish Xiphophorus maculatus (Osteichthyes: Poeciliidae) cultivated in São Paulo State, Brazil

“…(Lyan and Seng, 1979), Camallanus corderoi Torres, Teuber andMiranda, 1990 (Torres et al, 1990) and Camallanus cotti Fujita, 1927 (Font andTate, 1994;Rigby et al, 1997;Kim et al, 2002). On the other hand, the mean intensity was higher than the one registered by Torres et al (1991), in salmonids.…”

“…National and international transport of fish contributes on world and, in Brazil, Camallanus acaudatus and Camallanus tridentatus were found in Osteoglossum bicirrhosum and Arapaima gigas by Ferraz and Thatcher (1990). They could be seen into reared and native fish intestines (Amin, 1978;Baker, 1979;Ferraz and Thatcher, 1990;Lakshimi et al, 1990;Moravec 1994;Torres et al, 1991;Moravec, 1994;Martins et al, 2007). Their prevalence may reach 83.3% for both salmonids (Torres et al, 1990) and Poecilia reticulata (Kim et al, 2002) and 2.6% in Xiphophorus maculatus from ornamental fish in Florianópolis-SC (Piazza et al, 2006).…”