Sea Otters in the Literature: Strep Syndrome

Date: 1/17/2022

Hours: 1.5

Event: Reading sea otter papers

Today I read the 2 sea otter papers that Caroline sent:

Burek Huntington, K. A., Gill, V. A., Berrian, A. M., Goldstein, T., Tuomi, P., Byrne, B. A., Worman, k., and

Mazet, J. (2021). Causes of Mortality of Northern Sea Otters (Enhydra lutris kenyoni) in Alaska

from 2002 to 2012. Frontiers in Marine Science, 8, 105.

Gerlach-Miller, J., Esslinger, G. G., and Weitzman, B. (2018). Aerial Surveys of Sea Otters (Enhydra lutris)

in Lower Cook Inlet, Alaska, May, 2017. US Fish and Wildlife Service.

Gerlach-Miller et al., 2018 did an aerial survey in 2017 of the Western Lower Cook Inlet, Eastern Lower Cook Inlet, and Kachemak Bay. They found that Western LCI had an abundance of 10,737 sea otters, Eastern LCI had an abundance of 3,164, and Kachemak Bay had an abundance of 5,988.

They also added a table to show how over the years, the Kachemak Bay population of sea otters has been increasing. That being said, they believe that the sea otter population may be at its carrying capacity.

This is a good sign, as sea otters were almost extirpated during the fur trade. The authors suggest foraging studies be conducted in order to be able to estimate energy intake rates of sea otters which could tell us population status relative to carrying capacity.

Although sea otter populations have recovered since the 1900s, Burek Huntington et al., 2021 discussed how as sea otter populations increase, diseases also increase. In 2002 to 2012, there was an unusual amount of sea otters washing up in Homer, AK.

After performing lab tests on the carcasses, strep syndrome was the number one cause of death during this time. Strep syndrome is a bacterial infection most commonly caused by the bacteria Streptococcus infantarius subsp. coli. It was speculated that sea otters contacted this bacterium from their food. I looked more into this and found a study done by Counihan-Edgar et al., 2012 that found that blue mussels in the found near the Northern Sea otter stock of Alaska was found positive for this infection. They also found that these bacteria could live freely in the water, which is another way the sea otters were possibly contracting the infection. Another hypothesis on why these sea otters are from this infection was due to a possible infection from the phocine distemper virus. This virus causes harm to the brain and the heart and weakens the immune system which leaves the body defenseless against strep syndrome (Burek Huntington et al., 2021).

Counihan-Edgar, K. L., Gill, V. A., Doroff, A. M., Burek, K. A., Miller, W. A., Shewmaker, P. L., Jang, S.,

Goertz, C.E., Tuomi, P.A., Miller, M.A., Jessup, D.A., and Byrne, B. A. (2012). Genotypic

characterization of Streptococcus infantarius subsp. coli isolates from sea otters with infective

endocarditis and/or septicemia and from environmental mussel samples. Journal of clinical

microbiology, 50(12), 4131-4133.

Overall, I think that this information is very useful for creating a brochure for public outreach in order to give the public a population estimate, as well as help them understand what is happening with the sea otter population. These findings can also help the public in understanding how important it is to distance yourself from these animals, as they could be carrying a dangerous disease transmittable to humans and/or dogs. Burek Huntington et al., 2021 also mentioned how trauma such as boat strikes are another cause of death among sea otters since they can't always get out of the way of boats. Since there are sea otters in/near the harbor, it is important to notify the public so they can take appropriate measures to avoid hitting these animals. I hope to get started on making brochures, as well as continue to learn about sea otters and the threats that they face.

Date: 1/22/2022

Hours: 1.5

Event: Reading about strep syndrome in sea otters

Debbie sent us some more information regarding strep syndrome in sea otters:

N. Rouse et al.-AMSS Poster 1_2018 final 48x36 full size.pdf

Download PDF • 522KB

Rouse, N. M., Counihan, K. L., Boege Tobin, D. D., Goertz, C. E., and Duddleston, K. N. (2021).

Habitat associations between Streptococcus bovis/equinus complex and Streptococcus phocae,

the causative agents of strep syndrome in sea otters, and the marine environment. Marine

Ecology, e12689.

She also sent us another poster evaluating sea otter scat in the winter:

Scat_poster_final-Doroff,Corbell et al..pdf

Download PDF • 1.11MB

From the poster, there is a graph showing the diet of sea otters during the winter months, as this is less studied. The graph shows that mussels are less prevalent in their diet in the winter opposed to the fall, spring, or summer.

This made me wonder if strep syndrome was less prevalent in the winter months, since sea otters are feeding on mussels less in the winter. Some other questions I had include

• Is Streptococcus bovis/equinus and Streptococcus phocae found in other species that sea otters consume such as crabs, clams, and urchins?

• Are seals and other marine mammals also affected by this syndrome?

• How did the bacteria causing strep syndrome get to Kachemak Bay in the first place?

• Why did the mass stranding event end if the bacteria is still present?

These are questions I hope to find more research on in order to really understand this syndrome because it has/still is affecting sea otter populations in Kachemak Bay. Diondre and I have started to make a trifold on sea otters and are including strep syndrome as a threat to their populations.

Debbie also shared a Google Drive with us which includes a variety of sea otter references such as posters, presentations, theses, scientific papers, and so on. I looked at a presentation focusing on harmful algal blooms and how that can cause shellfish to accumulate domoic acid which can cause harm to sea otters as they consume the contaminated shellfish. Domoic acid poisoning causes a higher risk for cardiomyopathy which affects the ability for sea otters to move their lower limbs, making it hard to dive and hunt, ultimately leading to their death. I think these are important topics to discuss and Debbie mentioned how there is a Marine Mammal Forum in April and that Diondre and I could possibly present on sea otters.

Next Week

Next week I hope to meet with Debbie and/or Caroline to talk about education materials as well as get a map to see where appropriate places to perform beach walks are. We also need to meet with Jeff to get access to a truck for sea otter responses. It was interesting that there were no sea otter stranding reports this week. We also performed a beach walk for 2 hours on Wednesday (1/19/2022) on Bishop's Beach and, although we didn't see any marine mammals, we saw some cool kelp, oysters, worms, and a sea star. Using Debbie's sea star guides, we identified it as a true sea star.

As cool as invertebrates are, I hope to next week find sea otters or other marine mammals to get more internship hours as well as continue to practice responding to both live and dead marine mammals.