Abstract
An experiment was conducted to test the effect of the infection by the swimbladder nematode Anguillicola crassus on the survival of the European eel Anguilla anguilla when exposed to hypoxic conditions. Forty-four wild caught and naturally infected eels were placed in an aquarium filled with water from the fishing site (Vaccarès Lagoon, French Mediterranean coast). In this confined environment (271), under decreasing oxygen resources, the first eel death occurred after 45 h (O2 = 0.98 mg l−1) and the last one after 96 h (O2 = 0.48 mg l−1). After dissection and parasite examination, analyses revealed significant negative correlations between the time to death and various parameters of parasite pressure (e.g., number of lumen worms, parasite mass, health state of the infected organ). It was shown that the severity of damage to the swimbladder rather than the count of living parasites was the major contributing factor in explaining the variation in time to death. These semi-experimental data demonstrating an increased eel mortality rate under severe oxygen stress are discussed for their relevance under field conditions, especially during hot summer months.
[1] Ashworth S. T., Blanc G. 1997. Anguillicola crassus, un colonisateur agressif récemment introduit dans les stocks européens d’anguilles. Bulletin Français de la Pêche et de la Pisciculture, 344/345, 335–342. Search in Google Scholar
[2] Baruš V., Moravec F., Prokeš M. 1999. Anguillicolosis of the European eel (Anguilla anguilla) in the Czech Republic. Czechoslovak Journal of Animal Science, 44, 423–431. Search in Google Scholar
[3] Békési L., Hornok S., Székely C. 1997. Attempts to analyse Anguillicola crassus infection and the humoral host response in eels (Anguilla anguilla) of lake Balaton, Hungary. Acta Veterinaria Hungarica, 45, 439–445. Search in Google Scholar
[4] Burnham K.P., Anderson D.R. 1998. Model selection and inference: a practical information theoric approach. Springer-Verlag, New York. 10.1007/978-1-4757-2917-7_3Search in Google Scholar
[5] Csaba G., Láng M., Salyi G., Ramotsa J., Glávits R., Ratz F. 1993. The nematode Anguillicola crassus (Nematoda, Anguillicolidae) and its role in the death of eels in Lake Balaton during 1991. Magyar Állatorvosok Lapja, 48, 11–21. Search in Google Scholar
[6] De Casabianca M.-L., Laugier T., Marinho-Soriano E. 1997. Seasonal changes of nutrients in water and sediment in a Mediterranean lagoon with shellfish farming activity (Thau Lagoon, France). ICES Journal of Marine Science, 54, 905–916. http://dx.doi.org/10.1006/jmsc.1996.020110.1006/jmsc.1996.0201Search in Google Scholar
[7] Egusa S. 1979. Notes on the culture of the European eel A. anguilla in Japanese eel farming ponds. Rapport et Procès-Verbaux des Réunions du Conseil Permanent International pour l’Exploration de la Mer, 174, 51–58. Search in Google Scholar
[8] Gollock M.J., Kennedy C.R., Brown J.A. 2005. European eels, Anguilla anguilla (L.), infected with Anguillicola crassus exhibit a more pronounced stress response to severe hypoxia than uninfected eels. Journal of Fish Diseases, 28, 429–436. http://dx.doi.org/10.1111/j.1365-2761.2005.00649.x10.1111/j.1365-2761.2005.00649.xSearch in Google Scholar
[9] Haenen O.L.M., van Wijngaarden T.A.M., van der Heijden M.H.T., Höglund J., Cornelissen J.B.J.W., van Leengoed L.A.M.G., Borgsteede F.H.M., van Muiswinkel W.B. 1996. Effects of experimental infections with different doses of Anguillicola crassus (Nematoda, Dracunculoidea) on European eel (Anguilla anguilla). Aquaculture, 141, 41–57. http://dx.doi.org/10.1016/0044-8486(95)01213-310.1016/0044-8486(95)01213-3Search in Google Scholar
[10] Kirk R.S. 2003. The impact of Anguillicola crassus on European eels. Fisheries Management and Ecology, 10, 385–394. http://dx.doi.org/10.1111/j.1365-2400.2003.00355.x10.1111/j.1365-2400.2003.00355.xSearch in Google Scholar
[11] Knopf K., Mahnke M. 2004. Differences in susceptibility of the European eel (Anguilla anguilla) and the Japanese eel (Anguilla japonica) to the swim-bladder nematode Anguillicola crassus. Parasitology, 129, 491–496. http://dx.doi.org/10.1017/S003118200400586410.1017/S0031182004005864Search in Google Scholar
[12] Kobayaschi H., Pelster B., Scheid P. 1990. CO2 back-diffusion in the rete aids O2 secretion in the swimbladder of the eel. Respiratory Physiology, 79, 231–242. http://dx.doi.org/10.1016/0034-5687(90)90129-M10.1016/0034-5687(90)90129-MSearch in Google Scholar
[13] Lagler K.F., Bardach J.E., Miller R.R., May Passino D.R. 1977. Ichthyology. John Wiley & Sons, New York. 10.2307/1443299Search in Google Scholar
[14] Lefebvre F., Contournet P., Crivelli A.J. 2002a. The health state of the eel swimbladder as a measure of parasite pressure by Anguillicola crassus. Parasitology, 124, 457–463. http://dx.doi.org/10.1017/S003118200100137810.1017/S0031182001001378Search in Google Scholar
[15] Lefebvre F., Contournet P., Priour F., Soulas O., Crivelli A.J. 2002b. Spatial and temporal variation in Anguillicola crassus counts: results of a 4 year survey of eels in Mediterranean lagoons. Diseases of Aquatic Organisms, 50, 181–188. Search in Google Scholar
[16] McCallum H., Dobson A. 1995. Detecting disease and parasite threats to endangered species and ecosystems. Trends in Ecology and Evolution, 10, 190–194. http://dx.doi.org/10.1016/S0169-5347(00)89050-310.1016/S0169-5347(00)89050-3Search in Google Scholar
[17] Molnár K. 1993. Effect of decreased oxygen content on eels (Anguilla anguilla) infected by Anguillicola crassus (Nematoda: Dracunculoidea). Acta Veterinaria Hungarica, 41, 349–360. Search in Google Scholar
[18] Molnár K. 1994. Formation of parasitic nodules in the swimbladder and intestinal walls of the eel Anguilla anguilla due to infections with larval stages of Anguillicola crassus. Diseases of Aquatic Organisms, 20, 163–170. Search in Google Scholar
[19] Molná K., Baska F., Csaba G., Glávits R., Székely C. 1993. Pathological and histopathological studies of the swimbladder of eels Anguilla anguilla infected by Anguillicola crassus (Nematoda: Dracunculoidea). Diseases of Aquatic Organisms, 15, 41–50. Search in Google Scholar
[20] Molnár K., Székely C., Baska F. 1991. Mass mortality of eel in Lake Balaton due to Anguillicola crassus infection. Bulletin of the European Association of Fish Pathologists, 11, 211–212. Search in Google Scholar
[21] Molnár K., Székely C., Perényi M. 1994. Dynamics of Anguillicola crassus (Nematoda: Dracunculoidea) infection in eels of Lake Balaton, Hungary. Folia Parasitologica, 41, 193–202. Search in Google Scholar
[22] Moriarty C., Dekker W. 1997. Management of the European eel. In: Fisheries Bulletin (Eds. C. Moriarty and W. Dekker). Marine Institute, Dublin, 1–110. Search in Google Scholar
[23] Nagasawa K., Kim Y.G., Hirose H. 1994. Anguillicola crassus and Anguillicola globiceps (Nematoda: Dracunculoidea) parasitic in the swimbladder of eels (Anguilla japonica and A. anguilla) in East Asia: a review. Folia Parasitologica, 41, 127–137. Search in Google Scholar
[24] Nemcsók J., Bálint T., Fazakas J., Kátai F., Kiss I., Hieu L.H., Kufcsák O., Láng G., Polyhos C., Szabó I., Szegletes T. 1999. The contribution of a pyrethroid insecticide to the massive eel (Anguilla anguilla) devastation, in Lake Balaton, in 1995. Acta Biologica Hungarica, 50, 161–173. Search in Google Scholar
[25] Neumann W. 1985. Schwimmblasenparasit Anguillicola bei Aalen. Fischer und Teichwirt, 36, 322. Search in Google Scholar
[26] Schabuss M., Kennedy C.R., Konecny R., Grillitsch B., Reckendorfer W., Schiemer F., Herzig A. 2005. Dynamics and predicted decline of Anguillicola crassus infection in European eels, Anguilla anguilla, in Neusiedler See, Austria. Journal of Helminthology, 79, 159–167. http://dx.doi.org/10.1079/JOH200528110.1079/JOH2005281Search in Google Scholar
[27] Schmidt-Nielsen K. 1997. Animal physiology: adaptation and environment. Cambridge University Press, Cambridge. 10.1017/9780511801822Search in Google Scholar
[28] Sindermann C. 1987. Effects of parasites on fish populations: practical considerations. International Journal for Parasitology, 17, 371–382. http://dx.doi.org/10.1016/0020-7519(87)90112-310.1016/0020-7519(87)90112-3Search in Google Scholar
[29] Smith D.G., Duiker W., Cooke I.R.C. 1983. Sustained branchial apnea in the Autralian short-finned eel Anguilla australia. Journal of Experimental Zoology, 226, 37–43. http://dx.doi.org/10.1002/jez.140226010610.1002/jez.1402260106Search in Google Scholar PubMed
[30] Sures B., Knopf K., Kloas W. 2001. Induction of stress by the swimbladder nematode Anguillicola crassus in European eels, Anguilla anguilla, after repeated experimental infection. Parasitology, 123, 179–184. http://dx.doi.org/10.1017/S003118200100823X10.1017/S003118200100823XSearch in Google Scholar
[31] Székely C., Molnár K., Rácz O. 2005. Radiodiagnostic method for studying the dynamics of Anguillicola crassus (Nematoda: Dracunculoidea) infection and pathological status of the swimbladder in Lake Balaton eels. Diseases of Aquatic Organisms, 64, 53–61. Search in Google Scholar
[32] Würtz J., Taraschewski H. 2000. Histopathological changes in the swimbladder wall of the European eel Anguilla anguilla due to infections with Anguillicola crassus. Diseases of Aquatic Organisms, 39, 121–134. Search in Google Scholar
[33] Würtz J., Taraschewski H., Pelster B. 1996. Changes in gas composition in the swimbladder of the European eel (Anguilla anguilla) infected with Anguillicola crassus (Nematoda). Parasitology, 112, 233–238. http://dx.doi.org/10.1017/S003118200008481X10.1017/S003118200008481XSearch in Google Scholar
© 2007 W. Stefański Institute of Parasitology, PAS
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.