Acanthocephalans are intestinal parasites that use amphipods as their intermediate host. In the UK, greatest attention has been given to Pomphorhynchus laevis, which matures in freshwater fish such as chub (Leuciscus cephalus) and barbel (Barbus barbus), and cycles through Gammarus pulex. The larval stage (cystacanth) causes an orange spot to develop within the body of the intermediate shrimp host, increasing visibility to fish. Recent taxonomic studies have suggested two previously synonymised species of Pomphorhynchus, P. laevis and P. tereticollis, are genetically distinct. This has raised uncertainty over the identity, distribution and impact of these parasites in English rivers. This study provides clarity on the status of this parasite in England and Wales through application of citizen science to assist with sampling of infected shrimps. Morphological examinations of archived parasites (previously recorded as P. laevis) combined with genetic analysis of recently collected cystacanths have so far revealed only P. tereticollis. Work is underway to progress our understanding of the distribution, impact and ecology of this parasite in fisheries in light of these recent taxonomic changes.
