Barry, J.Newton, M.Dodd, J. A.Evans, DerekNewton, J.Adams, C. E.2021-07-272021-07-272017-01-13Barry, J., Newton, M., Dodd, J. A., Evans, D., Newton, J. and Adams, C. E. (2017) ‘The effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite Anguillicola crassus in the European eel Anguilla anguilla’, Journal of Fish Diseases, 40(9), pp. 1213–1222. doi: 10.1111/jfd.12596.0140-77751365-2761 (electronic)https://doi.org/10.1111/jfd.12596Publication history: Accepted - 10 November 2016; Published online - 13 January 2017.Infection patterns of the invasive Anguillicola crassus nematode were investigated in a population of the European eel Anguilla anguilla where parasite invasion is very recent, Loch Lomond, Scotland. Intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. Although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder parasites compared to larger eel with a predominance of fish (>60% contribution) in their diet. Within affected fish, a significant negative relationship was found between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in this recently infected host–parasite system. From a management perspective increasing our understanding of how infection intensity and repeated exposure is linked to resource use in an ecosystem is important for the future management of this endangered species in Europe.en© 2017 The Authors. Journal of Fish Diseases Published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Anguillicola crassuseelforagingontogenyparasite prevalenceArticle