Habitat selection and populations of Corynosoma (Acanthocephala) in the intestines of sea otters (Enhydra lutris) and seals.

K Shanebeck,K Lehnert,J Lakemeyer,U Siebert

doi:10.1017/s0022149x20000747

K Shanebeck, K Lehnert + Show 2 more

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https://doi.org/10.1017/s0022149x20000747

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Abstract

Acanthocephalans are common intestinal parasites of marine mammals, the most widespread of which is the genus Corynosoma. In this study, parasite infrapopulations of two closely related species of Corynosoma were examined: Corynosoma enhydri from sea otters (Enhydra lutris) in Alaska (n = 12) and California (n = 19), and Corynosoma strumosum from seals in Germany (n = 22). Prevalence of C. enhydri was 100% in Californian otters, with a mean abundance of 30, and 83% in Alaskan otters, with a mean abundance of 232. In seals, C. strumosum had a prevalence of 65%, with a mean abundance of 33. Female C. enhydri dominated both Californian (82%) and Alaskan (79%) infections, while, in seals, female C. strumosum made up 68% of the parasite population. Reproduction rates for C. enhydri, with 16% (California) and 18% (Alaska) of females mated, were low compared to C. strumosum in seals, of which 40% of females were mated. Habitat selection also differed significantly between the two species. Corynosoma enhydri was found most frequently in the second and third fifths of the small intestine, while C. strumosum was found most frequently in the fourth. The differences in habitat selection and prevalence analysed in this study may be related to a trade-off between growth and reproduction between the two species.

Highlights

Corynosoma enhydri (Acanthocephala) is the most common parasite of sea otters (Enhydra lutris) and the only one known to use them as their main definitive host (Hennessey & Morejohn, 1977; Margolis et al, 1997; Mayer et al, 2003)
Females made up 80.7% (±12.5) of southern sea otter intestinal parasite infrapopulations, with 16.9% (±6.7) of females mated
While there were limitations to this study, both in time and sample size, this project gave an invaluable look into an Downloaded from https://www.cambridge.org/core

Summary

Introduction

Corynosoma enhydri (Acanthocephala) is the most common parasite of sea otters (Enhydra lutris) and the only one known to use them as their main definitive host (Hennessey & Morejohn, 1977; Margolis et al, 1997; Mayer et al, 2003). C. strumosum infections can cause enteritis, damage to the villi and blockage of the lumen (Lehnert et al, 2007; Amin et al, 2011; Lakemeyer et al, 2020). It is unclear how large-scale infections may affect hosts, and how immune suppression or metabolic disruption may influence health impacts; though infections with Corynosoma semerme have been associated with colonic ulcers in Baltic grey seals (Lakemeyer et al, 2020)

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