13th Annual Sea Otter Awareness Week
September 20th to September 26th, 2015
This week, I discovered it was Sea Otter Awareness Week and I learned how vulnerable and important they are to our planet. In fact, since 1977 the southern sea otter has been listed as a threatened species under the Endangered Species Act. Today, the IUCN Red List states the status of sea otters (Enhydra lutris) as endangered.
Chuck Abbe (chuckthephotographer on flickr) / CC-by-2.0Besides being cute and playful, sea otters are incredibly important to the maintenance of shoreline ecosystems. Without sea otters, sea urchins and similar invertebrates can wipe out kelp forests.
Numerous species depend on kelp forests. I was amazed to find out from the NOAA that kelp forests are home to marine mammals, fish, invertebrates, and even birds. Plus, kelp protects shorelines from erosion and storm damage. For us, kelp forests remove massive amounts of carbon dioxide from the environment.
Up next is a succinct 2:38 minute YouTube video by BBC Earth Unplugged that brilliantly highlights amazing facts about sea otters.
Sweet Shell Smashers - Amazing Animal Babies - Sea Otters
Episode 7: Earth Unplugged (Published on December 27th, 2012)
The Challenges and Threats Sea Otters Face
When I perused the National Recovery Strategy for the Sea Otter (Enhydra lutris) in Canada, I was astounded by the following:
In California, disease in sea otters accounts for 40 percent of their mortality which compounds their low rate of population growth compared to other sea otter populations (Thomas and Cole 1996; Estes et al. 2003).
Oil spills, even small ones, have a devastating effect on sea otters. Oil destroys the water-repellent property of their fur and eliminates its air layer. It reduces their fur's protective insulation by a whopping 70 percent (Williams et al. 1988). And sadly, sea otters literally freeze to death.
Small oil spills can wreak havoc with the health of sea otters. In fact, sea otters are the most vulnerable to the harm caused by oil spills than any other marine mammal (Williams and Davis, 1995).
Oil gets into sea otters three ways: ingestion, skin absorption, and inhalation which harms many internal organ systems. What's more, fresh crude oil irritates the webbing of their hind flippers and sensitive membranes around the otters' eyes, nose, mouth, and urogenital tissues.
David Merrett (davehamster on flickr) CC-by-2.0According to a June 1st, 2012 post by Randall W. Davis titled Sea Otters and Oil: Avenues of Exposure and Health Effects, the five most important causes of death for oiled sea otters are:
1) Hypothermia (freezing to death)
2) Shock and secondary organ dysfunction
3) Interstitial emphysema
4) Gastrointestinal ulceration
5) Stress during captivity
Which Diseases Affect Sea Otters?
In order to maintain their high metabolic rate, sea otters must eat up to 30 percent of their body weight each day. And their diet consists mainly of invertebrate "filter-feeders" such as clams and mussels. Because clams and mussels literally filter particles out of sea water, they accumulate high levels of pollutants and diseases. When otters consume them, they are ingesting potentially lethal doses of contaminants, bacteria, and/or parasites.
But that doesn't explain it all. And in my article Opossums Are Beneficial to Have Around, I learned that birds, horses, and sea otters are at high risk of contracting a deadly disease known as sarcocystosis if they ingest opossum feces.
Well, it turns out that in the early 1900s, opossums were introduced to California. And as noted in other Paw Mane Fin articles, species that are introduced (and not native) to a region can have detrimental impacts on various species and their ecosystems.
Sarcocystosis can kill otters or cause brain damage that makes them more prone to deadly encounters with shoreline structures, boats, or sharks. Apparently, many otters do survive this parasitic infection, so scientists feel other factors are at play.
Cyanobacteria has also been linked to the deaths of California sea otters. This bacteria produces a potent microtoxin. It often appears like green neon-colored scum on the surface of lakes and waterways.
Lilian Carswell/USFWS on flickr / CC-by-2.0As mentioned in my Feeling Ducky? Fun Facts About Waddlers, throwing white bread into waterways (to feed ducks, for example) encourages the growth of harmful levels of algae and bacteria.
Massive amounts of microtoxin have been documented in areas like Santa Cruz County’s Pinto Lake and eventually this runoff flows into the ocean and accumulate in sea otter food.
Remember too, sea otters spend a great deal of time on the surface of coastal waters. And sadly, microcystin (or cyanoginosins) cause liver failure, heart and brain damage in otters.
"Here, around Monterey Bay, the storm sewers and lots of street drains go directly into the ocean. Since oil floats on water, the tons of oil that cars leak onto the streets, and the toxic chemicals and metals that it contains, go into the ocean. More oil reaches the oceans from street runoff every year by far than all oils spills in any year combined."
Wow, I think that with all the factors cited, I can now understand why sea otters (especially in California) are struggling.
A Southern Sea Otter Gets Weighed at Monterey Bay Aquarium
One of the key resources I found incredibly helpful for this piece was SeaOtters.com. And I couldn't have worded it any better than in Erin Loury's article The Land-to-Sea Link: Disease and Contaminants:
"Clusters of sea otter deaths tend to occur around areas of high human population. However, the influence of people may also offer otters some reasons for hope. Since humans are the source of many sea otter problems, we can also take actions to stop or lessen their impacts."
Some key ways we can help sea otters and all aquatic life are:
- Reduce your use of any plastic items (including plastic grocery bags and bottles).
- Use local hazardous waste sites to dispose of pesticides, solvents, medications, paint, batteries, electronics or caustic materials.
- Purchase only non-toxic, environmentally friendly household detergents and cleaners.
- Do not dump anything into storm drains. Keep in mind that everything that flows into a storm drain eventually makes its way into the ocean.
- Check your car for leaks and recycle the oil (if possible). Wash your car on an unpaved surface.
- Sweep your driveway and sidewalk instead of hosing them down.
- Buy biodegradable, recycled, compostable, sustainable, organic products whenever possible.
- Do not throw bread or food into waterways.
- Pick up litter along waterways or get involved in shoreline cleanups.
Taxpayers in California can donate to the California Sea Otter Fund via their income tax form 540. On line 410, labeled CA Sea Otter Fund (under contributions) you can fill out the amount you wish to donate. The California Sea Otter Fund has been extended until 2021.
This Sea Otter is Applauding Our Efforts, I Think
Chuck Abbe (chuckthephotographer on flickr) / Licensed under Creative Commons Attribution 2.0 Generic