Endangered Species: Sea Otter

 The Sea Otter

The Sea Otter is a cute and actually the smallest marine mammal in North America. The can get up to 4 feet long and up to 50 pounds. South America's Sea Otter is the smallest marine mammal in the world. Unlike other marine mammals, the sea otter doesn’t have a thick layer of blubber. To stay warm in chilly ocean waters, it wears the world's densest fur — at its thickest, this two-layer fur is made up of more than a million hairs per square inch. Another way the sea otter stays warm is with its high metabolism — it will eat about a quarter of its body weight each day (A 150-pound person would have to eat 35 to 40 pounds of food a day to match that). This helps it maintain an average body temperature of 100 degrees Fahrenheit. The current southern sea otter population averages around 3,000 individuals.  Since the California population has a limited range and is close to human activity, they are considered endangered. 

Habitat/Range

Southern sea otters can be found along California's central coast, from San Mateo County in the north to near Santa Barbara in the south. Northern sea otters are found along the coast of Alaska and Washington, and Russian otters are found in the Pacific Ocean off Russia and Japan. 

Role in the Ecosystem

The Sea Otter plays an extremely important role in their ecosystem. It’s a keystone species, which means that the health of sea otters is a good indication of the health of other species and ecosystems nearby.In the kelp forest, it eats sea urchins and other animals that graze on giant kelp. When urchins go unchecked, they create areas called “urchin barrens” where nothing else lives. With sea otters helping to keep the urchins under control, kelp forests can thrive and support a rich community of plants and animals. Similarly, in estuaries, otters keep eelgrass healthy by eating crabs, which in turn allows the sea slug population to thrive. These sea slugs then eat algae that would otherwise coat and smother the eelgrass that fish need for food and shelter.

Cause of Decline

Historically, sea otters numbered in the hundreds of thousands in the North Pacific Ocean, but due to the fur trade, their numbers plummeted in the early 1900s. In addition to the fur trade, the threat to the southern sea otter posed by oil spills prompted its listing as a threatened species in 1977. Humans are the biggest threat to sea otter populations. Direct conflict with humans, through shootings, fishing gear entanglements and boat strikes, take a toll on sea otters, but oil spills, pollution, disease and loss of kelp pose major threats.

Why Should we Care?

The sea otter isn’t just cute — it keeps local ocean ecosystems healthy. In Monterey Bay, specifically, the sea otter is important for kelp forest and estuary ecosystems. The sea otter is also a good indicator of ocean health. Since it is a top predator of invertebrates along the California coast, changes in the health of its population can make scientists aware of variations in the ocean environment itself. This is why we consider the sea otter a keystone species. Without sea otters, these grazing animals can destroy kelp forests and consequently the wide diversity of animals that depend upon kelp habitat for survival.  Additionally, kelp forests protect coastlines from storm surge and absorb vast amounts of harmful carbon dioxide from the atmosphere. 

Current Conservation Efforts

Researchers are working hard to gain a better understanding of what’s threatening sea otters so we can find ways to help them recover.  Determining precisely how all of the factors driving elevated mortality are impacting the overall health of the southern sea otter population and the nearshore marine ecosystem on which they and other species depend is critical.  The goal is development and implementation of effective, long-term management and mitigation strategies that can lead to the recovery and delisting of the species.

How Geography Can Help

To protect sea otters that were crossing roads in Moss Landing, CA, Defenders helped make the case for placing crossing signs and establishing slow speed zones, and we worked with local sea otter protection organizations to install wildlife monitoring cameras.

Ways to help

1. Reduce, reuse, recycle
2. Dispose of hazardous waste properly
3. Use nontoxic household cleaning products
4. Don't dump litter or materials into storm drains
5. Pick up after your pets
6. Purchase sustainable, recycled, biodegradable goods