Central PugetSound Marine Mammal Stranding Network

Do Pacific Northwest marine mammals carry antibiotic-resistant bacteria from land animals?

Antibiotic resistance, a global concern, is a significant health issue of animals and humans. Resistant bacteria, a growing presence in marine life, are derived from land via humans, animals, and agriculture. Antibiotic resistance is documented in multiple marine species. Data on resistance in marine species in Washington State's inland waters, known as the Salish Sea, is relatively limited.

Preliminary work reported resistance in young harbor seals (Phoca vitulina) in rehabilitation and in breath from local southern resident killer whales (Orcinus orca), as well anecdotal reports from stranding necropsies. A larger dataset with multiple species, age classes, and locales is warranted to determine if resistant bacteria exhibit patterns within this urban marine ecosystem, and if they pose a threat to other marine mammals and human health. So we set out to answer the question: What is the prevalence of resistant bacteria present in marine mammals of an urban ecosystem, the Salish Sea, in Washington State?

This crowdfunded and Wildlife Disease Association-supported project seeks to: detect and describe the presence and distribution of antibiotic resistance in two key Salish Sea marine mammal species; determine differences in resistance between harbor seals and harbor porpoises (Phocoena phocoena); and document geographic patterns. These species were selected because they are abundant and relatively site-specific within the Salish Sea. A cross-sectional sampling study is being conducted to calculate prevalence (%) of resistant bacteria from 69 dead-stranded harbor seals and 69 porpoise, of all age classes and sexes. The study area is divided into northern and southern sampling regions. We hypothesize that resistance prevalence will: be < 5% overall, differ between harbor seals and porpoises and between the two sampling regions. Sterile swabs of the intestines and lesions noted on necropsy are submitted for aerobic culture and sensitivity to a suite of 16 commonly used antibiotics using standard laboratory techniques.

Samples have been collected from ten harbor seals and 5 harbor (Table 1). Preliminary results (% of each species sampled to-date) indicate multi-drug resistant bacteria were detected in four seals (40%) and two porpoises (40%), respectively, with all age classes and sexes involved (see table attached at the end of this report). Swabs for culture and sensitivity were submitted by Central Puget Sound Marine Mammal Stranding Network (n=1), Washington Department of Fish and Wildlife (n=1), Cascadia Research Collective (n=4), The Whale Museum/San Juan County Marine Mammal Stranding Network (n=3), Sno-King Marine Mammal Response (n=2), Seal Sitters (n=1) and Port Townsend Marine Science Center/East Jefferson County Marine Mammal Stranding Network (n=1).

Genotyping and sequencing of E. coli cultures are ongoing. Study results will better define antibiotic resistance prevalence patterns and risk factors in Salish Sea marine mammals. In addition to Orca Network and Central Puget Sound Marine Mammal Stranding Network, project partners include Marine-Med , Washington State Department of Wildlife , Cascadia Research Collective, The Whale Museum/San Juan County Marine Mammal Stranding Network, Whatcom County Marine Mammal Stranding Network, World Vets, Port Townsend Marine Science Center, and Sno-King Marine Mammal Response. Initial support for this project was through Experiment.com , with additional support by the Wildlife Disease Association. 

YOUR SUPPORT through GlobalGiving provides additional funding for Dr. Norman's work to carry out this project, as well as her work with the Central Puget Sound Marine Mammal Stranding Network to respond to and investigate marine mammal strandings, perform necropsies and conduct research on the health of marine mammals of the Salish Sea. 

Links:

• More information about our Antibiotic Resistance Project here
• Hakai Magazine: Antibiotic-Resistant Bacteria in Marine Mammals
• Learn more about our Stranding Network from our website

• Antibiotic Resistance results as of March 2019 (PDF)
  

Central Puget Sound Marine Mammal Stranding 2018 Report

The Central Puget Sound Marine Mammal Stranding Network had a busy year despite reports of harbor seals being down by almost 27% from last year’s count of 209. However, the total number of reports this year was actually close to the average of the last five years. Seals are very mobile and come and go as they please, so this was no surprise - and since we have had an increase in the presence of Transient (mammal eating) orcas in our region in recent years, this likely is affecting the seal population as well.

From the chart accompanying this report you can see an increase in the number of calls of elephant seals and gray whales. Actually, many of these calls were duplicates about the same animal.  We had a gray whale wash up dead on West Beach, Whidbey Island in April. The necropsy showed that it died of malnutrition and heavy external and internal parasitism. Frequent follow up reports were made by our stranding network observers who were tracking the timing and stages of decomposition several times per week. Unfortunately the research was terminated before it was completed by the high tides that took the carcass out to sea.

There were few calls on molting elephant seals this year. The majority of calls received were from concerned residents and volunteers about our two elephant seal pups born on Whidbey. Elsie Mae, the female born in March of 2018, left her birthplace and swam about 70 miles to the San Juan Islands where she has been hanging out. She was tagged so her identification is absolute.

Ellison, the young male elephant seal born on Whidbey Island in March of 2015, has spent most of his time on a tiny nearby island where he is monitored by the local residents. He disappeared for several weeks and those “adoptive parents” became very concerned. There has been a rash of illegal shootings of California sea lions in Puget Sound this year, possibly because some folks think they eat too many salmon. Elephant seals do not eat salmon, but it would be quite difficult to tell the difference between an elephant seal and a California sea lion swimming in the water. Elephant seals eat deepwater invertebrates and fish, ratfish, rockfish, squid and octopus. Also they are capable of staying at sea anywhere in the temperate ocean for months at a time. Fortunately, after a few weeks Ellison returned to the island that he shares with a group of harbor seals. One resident monitor described Ellison, who will soon be a full-sized adult male, as “looking like a trident submarine that had been beached”. We hope to tag Ellison sometime early next year so he can be tracked when he leaves home.

Most of the reports of live whales go to our Orca Network Whale Sighting Network. However, we added a new category on the chart this year for 4 reports of sperm whales nearby. It is always exciting to have new species show up.

Included in the “other” category, not charted, were reports of several river otters, which are prevalent on our islands, but not marine mammals.  Also, an unknown container which turned out to be a portion of a floating dock, a 6-gilled shark, a mola mola, a walrus (no way), and an exciting find uncovered by an 8 month old yellow lab puppy. The artifact was identified by experts at the Burke Museum in Seattle as a mammoth tooth dating from the last ice age 13,000 years ago. Whidbey Island was formed by “glacial dump” as the ice receded, leaving many interesting finds as the ice melted. 

And we don’t even have to dig for them. 

Thanks for your support in keeping our Marine Mammal Stranding Network afloat!

Links:

• Central Puget Sound MMSN Webpage

• 2014 - 2018 Stranding calls by Species Chart (PDF)