Skip to main content
U.S. flag

An official website of the United States government

Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system

December 1, 2014

The processes promoting disease in wild animal populations are highly complex, yet identifying these processes is critically important for conservation when disease is limiting a population. By combining field studies with epidemiologic tools, we evaluated the relationship between key factors impeding southern sea otter (Enhydra lutris nereis) population growth: disease and resource limitation. This threatened population has struggled to recover despite protection, so we followed radio-tagged sea otters and evaluated infection with 2 disease-causing protozoal pathogens, Toxoplasma gondii and Sarcocystis neurona, to reveal risks that increased the likelihood of pathogen exposure. We identified patterns of pathogen infection that are linked to individual animal behavior, prey choice, and habitat use. We detected a high-risk spatial cluster of S. neurona infections in otters with home ranges in southern Monterey Bay and a coastal segment near San Simeon and Cambria where otters had high levels of infection with T. gondii. We found that otters feeding on abalone, which is the preferred prey in a resource-abundant marine ecosystem, had a very low risk of infection with either pathogen, whereas otters consuming small marine snails were more likely to be infected with T. gondii. Individual dietary specialization in sea otters is an adaptive mechanism for coping with limited food resources along central coastal California. High levels of infection with protozoal pathogens may be an adverse consequence of dietary specialization in this threatened species, with both depleted resources and disease working synergistically to limit recovery.

Publication Year 2014
Title Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system
DOI 10.1073/pnas.0806449106
Authors Christine K. Johnson, M. Tim Tinker, James A. Estes, Patricia A. Conrad, Michelle M. Staedler, Melissa A. Miller, David A. Jessup, Jonna A.K. Mazet
Publication Type Article
Publication Subtype Journal Article
Series Title Proceedings of the National Academy of Sciences of the United States of America
Index ID 70136064
Record Source USGS Publications Warehouse
USGS Organization Western Ecological Research Center