The impact of Anguillicola crassus on European eels

Abstract

The impact of the parasitic swimbladder nematode, Anguillicola crassus Kuwahara, Niimi & Itagaki, on European eel populations is assessed with reference to published research on its origin and rapid dissemination, life cycle and transmission dynamics, and its pathogenic effect. The parasite was originally endemic to East Asia, but has transferred from its native host, the Japanese eel, Anguilla japonica Temminck & Schlegel, to the European eel, Anguilla anguilla (L.) and American eel, Anguilla rostrata (Le Seur). Anguillicola crassus is a very successful colonizer and is now known to occur in four continents (Asia, Europe, Africa and America). The nematode can severely impair swimbladder function and has caused mortalities in both farmed and wild populations in the presence of other stressors. Anguillicola crassus may impair the capacity of European eels to complete the spawning migration, although direct evidence is not available to support this hypothesis. Areas for future research are recommended.K E Y W O R D S : Anguillicola crassus, eels parasite, nematode, pathology, swimbladder.

Assessing the freshwater distribution of yellow eel

“…However, today it is declining sharply throughout its distribution area (Moriarty and Dekker, 1997;Dekker, 2003b). Although we do not understand the exact causes of this decline, it is speculated that the main factors involved are probably changes in oceanographic conditions that are assumed to be linked to climate changes (Desaunay and Guérault, 1997;Knights, 2003;Bonhommeau et al, 2008), habitat changes and the obstruction of migration by dams and other physical obstacles (Feunteun, 2002;Laffaille et al, 2004Laffaille et al, , 2007, and the impact of parasites and chemicals (Robinet and Feunteun, 2002;Kirk, 2003). In this context, Russel and Potter (2003) suggested that the precautionary approach is the most appropriate way to consider European eel stock management.…”

Biogeographical Relationships of the Eel Parasite Anguillicola Crassus Revealed by Random Amplified Polymorphic Dna Markers (Rapds)

“…We did not find any significant correlation between the genetic distances and the dates of introduction of A. crassus in the different sites of this work (p = 0.48) (according to MORAVEC, 1992;BLANC, 1994;RAHHOU et al, 2001 andKIRK, 2003). On the other hand, we observed a significant correlation between geographical distances and dates of introduction of A. crassus in the different sites of this work (Mantel test with 1 000 permutations, p = 0.03).…”

“…Many works have shown that the effects on the European eels are much more important than those on the native Japanese eel (MORAVEC and TARASCHEWSKI, 1988;KENNEDY and FITCH, 1990;KØIE, 1991;MOLNAR et al, 1991;KNOPF and MAHNKE, 2004;MÜNDERLE et al, 2004). The rapid spatial extension of Anguillicola crassus has been reported (KIRK, 2003). The aim of our study was to compare parasite populations from the original population (providing from Anguilla japonica) and from different places where the parasite is now found in abundance, in order to discuss the dynamic of the invasion.…”

“…The first case of anguillicolosis in Europe has been described in Germany (NEUMANN, 1985;PETERS and HARTMANN, 1986). Since then, the data relative to its extension have been regularly published and has recently been update by KIRK (2003). The recent association between Anguillicola crassus and Anguilla anguilla is characterized by an important pathogenicity (KNOPF and MAHNKE, 2004;MÜNDERLE et al, 2004;SURES and KNOPF, 2004).…”

Un Outil D’aide Á La Gestion De L’anguille : Le Tableau De Bord Anguillle Du Bassin Loire

“…Soit par le Groupe National Anguille (ELIE et CLEMENT, 1984 ;RIGAUD, 1997 ;LAMBERT et FEUNTEUN, 1998), soit par divers auteurs (BRUSLE, 1994 ;, ces constats ont été maintes fois répétés au niveau national depuis 20 ans, mais aussi au niveau international (CASTONGUAY et al, 1994 ;MORIARTY et DEKKER, 1997 ;KIRK, 2003) avec, en parallèle les hypothèses émises pour expliquer ce déclin : causes marines, pollutions, pertes d'habitats, changements climatiques, surexploitation, parasitisme, contaminations chimiques, barrages, etc. (Figure 2).…”