Can sea otters save the world

Leisurely resting in the kelp near Race Rocks, British Columbia, Odin, a lone male sea otter with an injured eye, is one of the few of his kind making their way back into the Salish Sea. Named after the Norse god who sacrificed his eye for wisdom, Shawn Larson believes Odin may be the savior the world needs to combat climate change.

“Sea otters are a keystone species,” Larson, curator of conservation research at the Seattle Aquarium and research curator for The Whale Museum, explained during her talk, “Sea Otter, Enhydra lutris, Conservation – Can They Save the World?” The presentation took place on Aug. 20 in a packed Whale Museum hall.

As a keystone species, Larson explained, sea otters play a critical role in their ecosystem. Before delving into that important function, however, she described sea otter basics.

“Sea otters are true marine mammals,” Larson said. She added that sea otters are close to her heart, and are the species on which she wrote her college thesis.

The main difference between sea and river otters, she continued, is how long they remain in the marine environment. Sea otters spend most of their life in the ocean while river otters merely frequent water. Size is another major difference as sea otters are up to four times bigger than their river relatives.

Unlike other marine mammals, sea otters, or Enhydra lutris, have no blubber layer. Instead, they rely on a dense coat, which, Larson said is the thickest in the animal kingdom.

“Evolutionary wise, it would have been nice if they had at least a thin layer of blubber,” Larson said, as they can struggle for warmth without enough food or if they have a poor quality coat. Instead, these marine weasels rely on fur. Local naturalist and founder of Maya’s Legacy Whale Watching Jim Maya told the Journal that there are approximately 1,000,000 hairs per square inch in an otters coat. In comparison, a dog usually has around 60,000.

During the fur trade that lasted from 1741-1911. During peak hunting years, during the mid-1800s, according to harvest records that Larson presented, between 1804 and 1807 nearly 15,000 sea otters were killed. The last known native sea otter in Washington state, Larson said, was shot in 1910 near Willapa Bay. The following year, the Fur Seal Treaty was signed and although the agreement was intended to protect fur seals, Larson said it protected the handful of otters left as well. Today, the Enhydra lutris remains listed as a threatened species in the western part of Alaska and throughout California.

In the late 1960s, sea otters were reintroduced to Washington. Since that time, according to Larson, the population has grown at a rate of approximately 10 percent annually. Researchers estimated in 2017 that the state had around 2,058 sea otters.

One of Larson’s projects was studying the effects the fur trade had on sea otter genetic diversity. Searching Native American middens for per-fur era sea otter DNA, her study found on average that historic populations had a 0.79 genetic diversity rate. After near extinction, present-day populations have a 0.47 genetic diversity rate. Most animals that are not inbred have a genetic diversity rate of 0.79 — 0.80, she noted.

Over the last decade or two, with the Washington population inching upward, sightings of these otters in the San Juans are increasing. Larson explained, however, these creatures were never abundant in San Juan County and the inland sea.

During the 20 plus years he has been boating around the Salish Sea, Maya told the Journal, he has seen sea otters, including Odin, a total of 10 times.

A few identifying tips, he noted, are a round head rather than the pointier head of the locally common river otter and the coloring is more brown, as opposed to the gray head of a seal. They are frequently found laying on their back amongst the kelp.

The few Maya has seen, he told the Journal, were solitary, however, and he guesses they were young males scouting for females. Larson noted that by nature sea otters tend to be highly social animals.

“They like to be in large groups, or rafts,” she said. “They don’t care if you’re a brother, sister, cousin. However, they do sexually segregate (males tend to hang out with other males and females with other females).”

While Washington’s population may be slowly increasing, the number of sea otters in Alaska is decreasing. Larson explained that researchers suspect transient orcas may be the culprits. Seal populations in Alaska are also dwindling as a result of the growing number of transient orcas, so it’s possible they are also eating otters as an alternative.

A decline in otter populations is concerning because they could hold a key function in at least slowing global warming, Larson said.

Sea otters need to consume approximately 7-9,000 calories daily just to maintain their body weight, Larson noted, and a sea otter’s favorite meal is the sea urchin. Meanwhile, the preferred food source of urchins is kelp. Larson explained that kelp forests provide shelter for fish, including salmon, and other ocean creatures, but also convert carbon to oxygen in a manner similar to trees. Without sea otters keeping urchins in check, kelp forests become decimated, and more carbon dioxide remains in the atmosphere. In fact, Larson said, data shows kelp forests with sea otters sequester, or absorb, carbon dioxide 100 times more than those without.

In order for Odin and his clan to save the world, they will need clean seas, Larson said, free of toxic chemicals, fertilizers, pesticides and herbicides.

Oil spills need to be prevented, Larson added. More than 800 Alaskan sea otters died after the Exxon Valdez spill in 1989.

Because sea otters tend to stay in one area, state and local governments can be more effective in managing them than larger governmental bodies, Larson continued. Further research could also assist in better understanding the animals, thereby aiding conservation efforts.

“There is a lot we know, but there is also so much to find out about them,” Larson concluded.

 

Lootas, a female sea otter at the Seattle Aquarium with her second pup. Contributed by The Whale Museum and Seattle Aquarium.

Lootas, a female sea otter at the Seattle Aquarium with her second pup. Contributed by The Whale Museum and Seattle Aquarium.

Homer, a 25-year-old sea otter, and survivor of Exon Valdez oil spill, relaxes on her back. Contributed by The Whale Museum and Seattle Aquarium.

Homer, a 25-year-old sea otter, and survivor of Exon Valdez oil spill, relaxes on her back. Contributed by The Whale Museum and Seattle Aquarium.

Sea otter mom holds hands with her young pup. Photo contributed by The Whale Museum and Seattle Aquarium.

Sea otter mom holds hands with her young pup. Photo contributed by The Whale Museum and Seattle Aquarium.