Spatio-temporal dynamics of the nematode Anguillicola crassus in Northeast Tunisian lagoons

Abstract

Anguillicola crassus, parasite nematode of the European eel Anguilla anguilla, was recorded for the first time in Tunisia (1999) in the Ichkeul lagoon. Its distribution has since spread toward Bizerte and Ghar El Melh lagoons. The monthly epidemiological survey reveals that A. crassus exists throughout the year in the Ichkeul lagoon. In this lagoon, its prevalence is low in winter (12% in December), with a marked increases in the spring reaching a maximum in March (35%), before it starts to decrease in summer with a minimum in July (4.35%), which in turn is followed by a pronounced new rise in autumn (30% in November). However, mean intensity values do not show such a marked variation. The majority of the values are between 1 and 1.5 parasites per host. In the Bizerte and Ghar El Melh lagoons, the presence of this nematode is limited only to one to three months. Investigations in the Tunis lagoon did not reveal until now the presence of A. crassus. It has been observed that the length of the eel influences the prevalence values: A. crassus becomes less common if the length of the eel increases. Comparatively with the global epidemiological values of A. crassus signalled subsequently (1999) in the Ichkeul lagoon, we note that the present values record a clean increase. To cite this article: L.

Macroparasite communities in European eels,Anguilla anguilla, from French Mediterranean lagoons, with special reference to the invasive speciesAnguillicola crassusandPseudodactylogyrusspp.

“…This finding may not be a general trend in nematode transmission because other studies showed a positive (Thomas and Ollevier, 1992b;Lefebvre et al, 2002b;Audenaert et al, 2003) or no relationship (Würtz et al, 1998) between parasite abundance and the size of eels. Our results are consistent with those of Schabuss et al (1997) and Gargouri Ben Abdallah and Maamouri (2006), who showed a negative relationship between the two parameters. We showed an increase in A. crassus abundance as the age of eels decreased.…”

Contamination, parasitism and condition of Anguilla anguilla in three Italian stocks

“…A. crassus has been extensively monitored in the Camargue Lagoon and in other Mediterranean inland and coastal waters (Lefebvre et al 2002(Lefebvre et al , 2003Lefebvre and Crivelli 2004;Maillo et al 2005;Genc et al 2005;Esteve and Alcaide 2009). Other than a few notable exceptions, the quality of eels fished and farmed in the coastal areas of the rest of the Southern Europe and Northern Africa is almost unknown (Maamouria et al 1999;Rahhou et al 2001;Gargouri Ben Abdallah and Maamouria 2006).…”

Non‐native fish impacts on Mediterranean freshwater ecosystems: current knowledge and research needs

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