The liver fluke Campula oblonga from harbour porpoise Phocoena phocoena stranded on the Danish North Sea Coast: updated morphometric and molecular characteristics

One female specimen of the cetacean harbour porpoise Phocoena Phocoena (Linnaeus, 1758) was found dead on the North Sea coast of Denmark (Jutland) in May 2025. During necropsy severe pathological changes of the liver were observed (hepatic fibrosis, enlarged and thickened biliary duct walls) and when dissecting the biliary ducts six intact trematodes (total length 6.9-7.9 mm, width 1.9-2.0 mm) were recovered. Following conservation in formalin four parasites were haematoxylin stained, one specimen kept unstained but all five mounted for morphological analysis. The sixth specimen conserved in 70% ethanol was subjected to DNA purification and subsequent PCR and sequencing. All the parasites were identified as fully adult Campula oblonga (Cobbold, Trans Linnean Soc Lond 22(3):155-172, 1858). Morphometric, morphological and molecular data (NADH dehydrogenase, subunit 3 (ND3), mtDNA) are presented and indicate close relation with previous isolates from the North and Baltic Seas but a lower similarity to Pacific conspecifics.