| Summary: | 34th European Cetacean Society Conference, O Grove, 16-20 April 2023 Anisakis nematodes are parasites that infect cetaceans worldwide, but can accidentally infect humans and are a growing cause of human health concern. They infect fish and squid as paratenic hosts, and are transferred to cetaceans when they consume infected prey. Once in the cetacean stomach, they can penetrate the mucosa where they grow until reaching maturity, having pathological effects such as ulceration. Anisakis eggs are dispersed by cetaceans, thus closing their life cycle. However, parasite flows from prey to individual cetaceans and populations have not been quantified. In this study, we used a dataset spanning 20 years on common dolphin diet in Galicia, as well as an epidemiological survey of commercial fisheries from 2013-2015 in the area, coupled by means of generalized additive models (GAM) predicting Anisakis abundance based on fish length. We estimate that around 70 Anisakis/day or around 26000 Anisakis/year are being transferred on average to common dolphins in the Atlantic waters of the Iberian peninsula from their main prey species (species making up ~87% of their diet), with blue whiting being an especially important source, followed by hake, sardine and mackerel. Extrapolating these numbers to the population level suggests a yearly transfer of over 4000 million Anisakis from fish to common dolphins. While results are congruent with previously reported high prevalence of infection in stranded delphinids from the NEA and the Mediterranean, it is also apparent that numbers found in individual dolphin stomachs represent only a small proportion of the numbers ingested, suggesting substantial throughput. Further investigation of the trophic transfer of Anisakis is important to understand infection levels in marine biota and risks to human consumers of marine fish No
|
|---|