Serologic Surveillance of Pathogens in a Declining Harbor Seal (Phoca vitulina) Population in Glacier Bay National Park, Alaska, USA and a Reference Site

A declining harbor seal population in Glacier Bay National Park, Alaska, showing over 70% decline since 1992, was found to be immunologically naïve to distemper viruses and other pathogens. Serologic surveillance conducted between 2007 and 2008 revealed low prevalence of antibodies against Leptospira spp., with no detectable serum antibodies for Toxoplasma gondii, morbilliviruses, or Cryptosporidium in fecal samples. Giardia was detected in 6% of fecal samples from Glacier Bay, while no antibodies were found in reference samples from Kodiak Island. The study suggests that pathogens are unlikely to be the primary cause of the population decline, highlighting potential vulnerabilities to emerging diseases due to limited immunological exposure.

Hueffer, K., Holcomb, D., Ballweber, L. R., Gende, S. M., Blundell, G., & O’Hara, T. M. (2011). Serologic Surveillance of Pathogens in a Declining Harbor Seal (Phoca vitulina) Population in Glacier Bay National Park, Alaska, USA and a Reference Site. Journal of Wildlife Diseases, 47(4), 984–988. https://doi.org/10.7589/0090-3558-47.4.984