Having just moved to California last month, the first time I saw a sea otter in the wild was only a few weeks ago. I stood on the dirt road above North Harbor in Moss Landing, binoculars pressed to my eyes, watching a group of bachelor males. Some were napping, covering their eyes with their front paws as they floated on their backs, while others foraged, diving under the water and then reappearing with a mussel.
As I watched this group, what I was most struck by was their fur. Like rain on a raincoat, water beaded off it in rivulets after an otter resurfaced. It dried out quickly, returning to a luxurious chocolate brown fluff in just a few minutes of floating in the sun. It was at once beautiful and painful. I marveled at the sight, while at the same time realizing that this must have been what drew the attention of European fur traders when they first encountered sea otters – and what would ultimately lead to the loss of so many of them.
In the 18th and 19th centuries, sea otters were systematically hunted for their dense fur, so much so that they were nearly driven to the point of extinction. They suffered massive population depletions across their native range along vast stretches of the North Pacific rim from Japan to Baja, Mexico. In California, a small group of about 50 otters tucked away in the rugged Big Sur coastline near Bixby Creek managed to escape the fur trade. Since then, these southern sea otters (a subspecies now distinct from their northern relatives) have expanded their range to include the central California coast from Half Moon Bay to Point Conception.
More Than Just a Cute Critter
The loss of sea otters is more important than just the depletion of one species, because they play a disproportionately large role in their ecosystem – a trait qualifying them as keystone species. In fact, sea otters are the subject of one of the most well-known trophic cascade studies – research about what happens to an ecosystem when one species is removed.
In the 1970s, scientists demonstrated that areas without sea otters in the western Aleutian Islands were associated with kelp deforestation, while areas harboring local sea otter populations had healthy kelp forests. The link, they found, was that sea otters control the sea urchin population, one of their favorite meals, which translates to less kelp-munching by the urchins. By acting as the “guardians of the kelp,” sea otters also act as the protectors of the various species that depend on kelp forests, including several types of commercially important fish.
Recently, sea otters were discovered to also play a role in maintaining the balance in the eelgrass estuary ecosystems that they inhabit. By eating crabs, sea otters limit the ability of the crabs to consume sea slugs. In turn, the healthy sea slug populations are better able to limit algae growing on eelgrass, which allows the eelgrass to continue to take up sunlight in order to photosynthesize. Since sea otters have returned to Elkhorn Slough – an eelgrass marsh bordering Half Moon Bay – so has the eelgrass and all its dependent species.
The keystone role played by sea otters benefits more species than just the creatures and plants that share their ecosystems. By maintaining healthy kelp forests, for example, sea otters indirectly reduce the amount of greenhouse gases in the atmosphere, because kelp is capable of storing huge amounts of atmospheric carbon. Also, by limiting algae and allowing eelgrass to flourish, sea otters are combatting the effects of nitrogen-rich run-off from agricultural fields that cause harmful algal blooms.
Safeguarding Sea Otters
Defenders is working hard to protect these charismatic critters by collaborating with other organizations to install speed humps at popular sea otter road crossings and building partnerships with coastal businesses to advocate for sea otter range expansion efforts.
Without these furry, petite marine mammals, central California wouldn’t have its healthy coastal ecosystems or the profitable coastal tourism, recreation, and wildlife watching industries that depend on them. In honor of all that sea otters do for the ecosystems they inhabit, we are happy to celebrate Sea Otter Awareness Week (this week and every week!) and we hope you will too!
Here are some actions you can take to help sea otters repopulate the Pacific coast and continue to play their important ecological role:
- If you see wild sea otters in central California, do not disturb them. Rest is even more important for sea otters than it is for many other animals. This is because sea otters must spend so much time foraging to get enough food to maintain the high internal body temperatures they need to survive in the cold waters of the Pacific.
- Never approach sea otters that are hauled out on shore, and if you’re in a kayak, maintain a distance of at least five boat-lengths.
- Avoid pouring chemicals down the drain or flushing cat litter. These products contain harmful contaminants and disease organisms that can affect sea otters through wastewater disposal in the ocean, even after the water has been treated.
- If you file income taxes in California, you can check a box on your tax return under the Voluntary Contributions section to contribute to the California Sea Otter Fund. These proceeds help support sea otter research and public education projects by the California Department of Fish and Wildlife and the California Coastal Conservancy. Any amount helps!