In Sickness and in Health: Parasites of Stranded Pacific Harbor Seals ( Phoca vitulina richardii ) in Northern Oregon and Southern Washington
Parasites have the capability to infect virtually every living organism on the planet and have adapted to infiltrate every trophic level. Many species have complex indirect life cycles and rely upon hosts at different levels of the food web for growth and reproduction. In the marine environment, hav...
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| Format: | Text |
| Language: | English |
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PDXScholar
2022
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| Online Access: | https://pdxscholar.library.pdx.edu/open_access_etds/6074 https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=7145&context=open_access_etds |
| Summary: | Parasites have the capability to infect virtually every living organism on the planet and have adapted to infiltrate every trophic level. Many species have complex indirect life cycles and rely upon hosts at different levels of the food web for growth and reproduction. In the marine environment, having a high level of parasite diversity is thought to indicate a more stable ecosystem than an environment with low parasite diversity. As one of the top predators in their environment and because of their amphibious behaviors, pinnipeds (seals and sea lions) are exposed to a wide variety of parasites, making them ideal for parasite research. One of the most common and widely distributed pinnipeds is the harbor seal, Phoca vitulina. While parasitic infections are common in harbor seals, they are often overlooked unless they have a direct impact on human health or the fisheries industry. Although there have been recent studies conducted on the parasites of Pacific harbor seals, P. vitulina richardii, along the coasts of California, Washington, and Alaska, there have been no reports for Oregon since the 1970’s. Earlier studies in Oregon looked at parasite presence and diversity, but lacked any in-depth analyses on parasite prevalence with host characteristics like sex, age, health status, season, or over time. The Northern Oregon/Southern Washington Marine Mammal Stranding Program (NOSWSP; Portland State University, Department of Biology) responds to stranded marine mammals from Tillamook, OR through Long Beach, WA. These are routinely necropsied and all are examined for parasites. Pacific harbor seals are one of the most commonly stranded pinnipeds in the NOSWSP area. We examined and collected parasites from 53 stranded Pacific harbor seals between the years of 2018-2019. Parasites were collected from the heart, lungs, stomach, and intestines of each seal and found in 51 of the 53 processed seals (96% overall parasite prevalence). Nematodes were found in 43 seals (81% prevalence) and in each organ examined (heart, ... |
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