Richness and diversity of parasite communities in European eels Anguilla anguilla of the River Rhine, Germany, with special reference to helminth parasites

Abstract

A total of 121 European eels (Anguilla anguilla) from 2 sampling sites on the River Rhine were investigated in respect of their parasite communities. Special attention was given to the swim bladders, intestines, gills and fins of the fish. Twelve different parasite species were found to live in and on the eels. Data from each sampling site were kept separate. Parasites found in descending order of prevalence were: Anguillicola crassus, Trypanosoma granulosum, Myxobolus sp., Paratenuisentis ambiguus, Pseudodactylogyrus sp., Bothriocephalus claviceps, Myxidium giardi, Pomphorhynchus laevis, Trichodina sp., Raphidascaris acus, Acanthocephalus lucii and Acanthocephalus anguillae. Significantly different prevalences were reported for L3 larvae of A. crassus, adult P. ambiguus, B. claviceps and Myxobolus sp. at the 2 sampling sites. The highest number of parasite species was recorded from the intestine, which contained up to 6 different helminths. The coexistence of the acanthocephalans P. laevis and P. ambiguus, which showed clear patterns of distribution within the intestine of the respective hosts, was reported for the first time. Up to 3 different helminth species were found in the intestine of individual fish. Among those, acanthocephalans were the most prevalent worms with the eel-specific parasite P. ambiguus as the dominant species not only of the intestinal but also of the total component communities. Both infra and component communities exhibited low diversity and were dominated by this single species. The evenness reached only approximately 50% or less and it remained unclear why the helminth communities of the eels from the River Rhine with its huge catchment area exhibit such a low parasite diversity and high dominance.

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

“…The two strict eel specific microparasites found in our study, Myxidium giardi and Eimeria anguillae, are widespread parasites of the European eel (Copland 1981, Orecchia et al 1987, Køie 1988, Saraiva and Chubb 1989, Benajiba et al 1994 On the other hand, based on both measures of morphological features and sites of infection, neither of the Zschokkella species found seems to be Z. stettinensis, the only reported species in the European eel (Molnár et al 1986). An obvious difference between our study and previous ones is the total lack of the flagellate Trypanosoma granulosum in our study, but this species has been found in most other similar studies in very high prevalence (Orecchia et al 1987, Køie 1988, Saraiva and Chubb 1989, Mo and Sterud 1998, Sures et al 1999, Sures and Streit 2001, Outeiral et al 2002, Aguilar et al 2005.…”

“…During the last decades, extensive research on the parasite fauna of the European eel has been carried out in many European countries (e.g. Køie 1988, Kennedy 1997, Borgsteede et al 1999, Sures et al 1999, Saraiva et al 2005. To date, observations on parasites of Icelandic freshwater fishes have been limited; only few papers published, focusing on parasites of salmonids (Stephenson 1940, Brinckmann 1956, Baer 1962, Richter 1981, Richter 1982a, b, c, Malmquist et al 1986, Frandsen et al 1989, Kristmundsson and Richter 2002-2003 and threespined sticklebacks (Blair 1973).…”

Evaluation of an ELISA and immunoblotting for studying the humoral immune response in Anguillicola crassus infected European eel Anguilla anguilla

“…In this study it could be demonstrated that antibodies raised against Raphidascaris acus cross-react with at least 3 antigens from the body wall of Anguillicola crassus. As R. acus was also found at the sampling sites of the eels used in the present study (Sures et al 1999b), the cross-reactivity of antibodies against R. acus with body-wall-associated antigens of A. crassus probably contributes to the false positive results yielded by ELISA.…”

Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany

“…Conneely and McCarthy, 1986;Køie, 1988a;Kennedy, 1993Kennedy, , 1997Schabuss et al, 1997;Kennedy et al, 1998;Sures et al, 1999;Di Cave et al, 2001;Aguilar et al, 2005;Kristmundsson and Helgason, 2007). Investigations on the parasite fauna of European eels in marine habitats (Outeiral et al, 2001(Outeiral et al, , 2002Kristmundsson and Helgason, 2007) are scarce.…”