biostudies-literatureUnknown151(7)Zintl AStranded seals are often infected with a broad range of parasites, although whether they are the cause of significant morbidity or an incidental finding is usually unclear. In this study we used stable isotope ratio analysis, a method frequently used to investigate food webs, to explore the extent to which common seal parasites feed directly on host tissue and fluids or absorb host-derived metabolites, which in turn may give an indication of their potential impact on the host's health. The trophic discrimination factor Δ¹⁵N for the nasal mite, <i>Halarachne halichoeri</i>, was mostly positive, ranging between −0.015 and 3.2‰ (<i>n</i> = 6), while for the Acanthocephalan worm, <i>Corynosoma strumosum</i> and the anisakid nematode, <i>Pseudoterranova decipiens</i>, Δ¹⁵NParasitology744-752https://www.ebi.ac.uk/biostudies/studies/S-EPMC11474010biostudies-literatureUse of stable isotope ratio analysis to investigate the biology and clinical significance of seal parasites.PMC11474010Schmidt OZhang HZintl ASaint-Marc AToomey OSchertzer JJahns HImlau MfalseUse of stable isotope ratio analysis to investigate the biology and clinical significance of seal parasites.Stranded seals are often infected with a broad range of parasites, although whether they are the cause of significant morbidity or an incidental finding is usually unclear. In this study we used stable isotope ratio analysis, a method frequently used to investigate food webs, to explore the extent to which common seal parasites feed directly on host tissue and fluids or absorb host-derived metabolites, which in turn may give an indication of their potential impact on the host's health. The trophic discrimination factor Δ¹⁵N for the nasal mite, <i>Halarachne halichoeri</i>, was mostly positive, ranging between −0.015 and 3.2‰ (<i>n</i> = 6), while for the Acanthocephalan worm, <i>Corynosoma strumosum</i> and the anisakid nematode, <i>Pseudoterranova decipiens</i>, Δ¹⁵N2024-01-01T00:00:00Z2024 Jun2026-07-15T04:02:16.023Z2025-04-04T23:50:49.071ZS-EPMC114740103932048310.1017/S003118202400074X