Published May 8, 2025
BY ABBY COE
With their velvety fur and playful personality, sea otters, the cuddly creatures of the coast, need some help.
Beginning in the 1700s, sea otters have been a staple of the California coast, with archaeological evidence supporting the fact that Indigenous people highly valued their presence, says the Monterey Bay Aquarium. From 1984 and beyond, the aquarium has been dedicated to educating the public on sea otters through their exhibition and rehabilitation efforts. As a result of their endeavors, they have made significant progress in restoring the southern sea otter population, but there is still more to be done.
Despite his specialty being in elephant seals, Dr. Patrick Robinson, the director of the Año Nuevo Natural Reserve, has facilitated several sea otter observations in the area.
Otters, the ever-fluffy charmers of coastal tourists and locals, spend on average five hours a day grooming and playing. courtesy of CREATIVE COMMONS
“Sea otters used to be quite abundant along the California, Oregon, Washington and Alaskan coastline and then [humans] hunted them to near extinction,” says Robinson.
Miraculously, a small group of otters survived near Big Sur, as the area was well-protected, and hunters were deterred from pursuing them. Later in 1972, the Marine Mammal Protection Act was implemented, allowing the otters to repopulate.
Marine-loving Southern California native Dr. Nicole Thometz-Tomoleoni, an associate professor at the University of San Francisco and specialist in marine mammal physiology, ecology and behavior, claims the species is vital to the coastal environment.
“They have this huge role in their ecological environment that makes them this keystone species that helps keep kelp forests healthy [and] seagrass ecosystems healthy,” Thometz-Tomoleoni says.
In addition to Fisherman’s Wharf, sea otters also find refuge in Elkhorn Slough, California’s second largest estuary. courtesy of CREATIVE COMMONS
A keystone species is a species that has such a drastic impact on the environment, that if they were removed, the ecosystem would collapse. Otters fall into this category not because there’s especially a lot of them, but because they eat such an exorbitant amount.
“They do have such a high metabolic rate and they require so much food [that] any sort of disturbance that’s going to limit their resting time or cause them to expend more energy than they need could be a problem for the sea otters,” Thometz-Tomoleoni adds.
Dr. Terrie Williams, director of Marine Mammal Research at University of California, Santa Cruz, affirms how the otters are at carrying capacity, meaning that there’s just enough food for the otters that are on the Monterey coast at present.
“Otters will go wherever there’s food,” says Williams. “They eat a lot, and because of that they’re just so food dependent so if there is a resource that they can take advantage of they will.”
The sea otters pictured here are of the Monterey Bay Aquarium, one of the highlights for tourists in California. courtesy of CREATIVE COMMONS
Once food runs out, it will become challenging for the otters to repopulate as much as they have been, which leads researchers to look at another cause for concern: sharks. A common predator in California’s central and southern coastal waters, white sharks commonly think of sea otters as prey, but it is often a matter of misidentification. This usually leads to higher mortality rates for the otters, says Robinson. Since the shark’s metabolism is increasing, notes Williams, it makes them a dangerous predator.
“There’s no evidence to suggest that white sharks are eating sea otters,” says Thometz-Tomoleoni, “but they are biting them and killing them in really high numbers so that’s one reason why they could be not expanding as far north as quickly as we think they should.”
In addition to sharks, killer whales are also becoming an increasing threat, with an uptick in their diet of sea lions and longer residences near the sea otters’ environment.
Tagged as “built wrong” by Dr. Williams, sea otters have a water repellent coat that allows them to float on water. courtesy of CREATIVE COMMONS
“Because of the events in Alaska I just wonder if there will come a time when the killer whales are coming down [and] might try to take a sea otter,” says a concerned Williams.
If killer whales learn that behavior, that will most likely change the entire dynamic of the ecosystem, including shifting food resources and environment alterations due to climate change.
In order to take action quickly and effectively, teams do an autopsy on some of the otters to deduce whether they died from anything other than sharks, whether environmental or human. With humans and warm water events threatening their ecosystem, otters can become susceptible to overexertion.
Williams confirms that a changing environment poses a challenge to the otters.
“It’s trying to figure out the otters’ role in all of this and then how these shifts that are happening with a lot of the sea otter prey that are occurring with warming water, how that would affect the sea otter survival also,” the UCSC director adds.
Ever the optimist, Thometz-Tomoleoni contends that her role is to contribute to the future survival of the species by reducing pollution and further human implications from the environment: “My hope is that we can keep our coastline healthy enough that over time sea otters recolonize those former parts of their range.”
