Parasitic infections in the East Asian finless porpoise Neophocaena asiaeorientalis sunameri living off the Chinese Yellow/Bohai Sea coast

Parasitic disease is among the major causes of health problems in marine mammals. However, little information on parasitic species composition and infection levels in finless porpoises (Neophocaena spp.) is available. In this study, we report the first systematic survey on parasitic infections in the East Asian finless porpoise N. asiaeorientalis sunameri (EAFP) living off the Chinese Yellow/Bohai Sea coast. Using both morphological and molecular methods, 5 parasitic helminths were identified: Campula oblonga in the liver and pancreas; Synthesium seymouri in the pyloric stomach and duodenum ampulla; Anisakis pegreffii in the forestomach, main stomach, and esophagus; Halocercus sp. in the lungs; and Crassicauda magna in the mammary glands and muscle. Among these helminths, C. oblonga (80.7%), S. seymouri (80.7%), A. pegreffii (80.7%), and Halocercus sp. (77.4%) were the most prevalent, whereas C. magna (6.5%) were only ob served in 2 EAFP individuals. All juvenile and adult EAFPs were parasitized by at least 3 parasites species (C. oblonga, S. seymouri, and A. pegreffii), whereas in neonates, only Halocercus sp. were detected. We observed no significant difference in parasite prevalence between males and females. In addition, A. pegreffii and C. magna represented new infection records in Neophocaena. A pathological examination associated with parasitic lesions in EAFPs showed damage or destruction of cells or tissues to some extent. This study represents the first systematic survey on parasitic infections in EAFPs, providing important and valuable parasitological information for the research and conservation of this coastal marine mammal.