Abstract
Short-beaked common dolphins are important top predators in marine ecosystems, and inevitably they encounter a range of pressures in their environment. Parasite infections pose one such possible pressure and examining parasite burdens of common dolphins, and any possible impacts of infection, enables us to better understand these pressures. Here we examined the stomach parasite burden of 69 stranded common dolphins collected along the Irish coastline between 2017–2019. After isolating the parasites from the stomachs, all were identified as nematodes belonging to the genus Anisakis. Additional to adult nematodes, L3 and L4 larval stages were observed. A total of 319,344 anisakid specimens were estimated from all stomach compartments of the animals. Parasite prevalence was 94%, mean abundance was 4,630 worms, and mean intensity was 4,910 worms. A generalised linear model with negative binomial error structure revealed that dolphin body length, nutritional status and year of stranding were significantly associated with parasite burden. The results presented highlight the high parasite burdens that may be carried by common dolphins and their potential interaction with health parameters such as nutritional status. To gain a comprehensive overview it is important to include parasite infection investigations along with other parameters when evaluating the health status of marine mammals.