Long-term investigation of the composition and richness of intestinal helminth communities in the stocked population of eel, Anguilla anguilla, in Neusiedler See, Austria

Abstract

Data from a long-term study of the intestinal helminth parasite community of eels, Anguilla anguilla, stocked into the shallow eutrophic Neusiedler See, Austria, were collected over an 8 year period (1994-2001). In total, 720 eels from 2 sampling sites were examined. The parasite community showed characteristics similar to those in the natural eel populations in rivers of the UK and mainland Europe: it was species poor, with only 5 species (Acanthocephalus lucii, Acanthocephalus anguillae, Raphidascaris acus, Proteocephalus macrocephalus, Bothriocephalus claviceps) comprising the component community and a maximum infracommunity richness of 4 species. Over the period, the intestinal parasite community of the sampling site in Illmitz, which was originally dominated by A. lucii, changed. As levels of A. anguillae increased to a point at which it dominated the community, diversity increased whilst dominance of a single species decreased. By contrast the community in the southern sampling site remained rather constant with a continuous high infection level of A. anguillae and low abundance of A. lucii. Both acanthocephalan species exhibited higher infection levels in larger eels and in different seasons of the year and the infection parameters were significantly different between the years of study. The significant differences in the infection levels of the 2 acanthocephalan species at the 2 sampling sites were surprising as both acanthocephalan species use the same intermediate host, Asellus aquaticus, and the sampling sites were in close proximity and were similar in terms of water quality, host size and invertebrate abundance. Differences in the fish communities of the 2 sampling sites and eel movements rather than interspecific competition are discussed as possible explanations for the differences in the parasite communities of the 2 sampling sites.

Parasite communities of eels Anguilla anguilla in freshwater and marine habitats in Iceland in comparison with other parasite communities of eels in Europe

“…Aguilar et al 2005, Saraiva et al 2005, or logarithm with log base two (log 2 ) (e.g. Norton et al 2003, Schabuss et al 2005). Calculations using these two different logarithms give considerably different values and hence comparing diversity characteristics data derived from calculations with different logarithms calls for recalculations or else the comparison is meaningless.…”

Linking species abundance distributions and body size in monogenean communities

“…The concept of numerical dominance has been widely used in parasite community ecology (e.g. Salgado-Maldonado and Kennedy 1997;Gutiérrez 2001;Sures and Streit 2001;Schabuss et al 2005). However, it is applied mainly as a descriptive tool to classify some species as dominant and others as rare based on arbitrary threshold values of prevalence or intensity of infection.…”

Do eel parasites reflect the local crustacean community? A case study from the Rhine river system

“…Until now, only two papers (Sures et al, 1999;Sures & Streit, 2001) have dealt with eel parasites in this large river system. The parasite fauna of the European eel throughout Europe is well investigated and all parasite species reported here are also known from other locations in Europe (see, for example, Kennedy, 1993;Sures et al, 1999;Sures & Streit, 2001;Norton et al, 2003;Schabuss et al, 2005), except for the unidentified acanthocephalan and trematode species. At freshwater locations, digenean trematodes are usually absent from eels, whereas in brackish water and seawater these trematodes are common parasites (Køie, 1988).…”