Discussion

Over the last 30 years, the recorded parasite diversity of British freshwater fish has significantly increased as a consequence of greater detection efforts and the introduction of new species with global fish movements. For those managing freshwater environments understanding changes in the parasitological fauna represents a significant challenge, and there is a need to balance surveillance efforts with risk of disease. Globally, the Monogenea are among the most successful and widespread group of aquatic parasites, which have the potential to cause significant fish mortalities. However, our current estimate of mongenean diversity is thought to be a gross underestimate. Here, we highlight current issues with detecting and identifying monogeneans, and use Pellucidhaptor pricei, Thaprocleidus vistulensis and Gyrodactylus sprostonae as examples of recent additions to the British parasitological fauna. We also discuss the potential implications of these and other newly emerging monogeneans for British freshwater fisheries.