Alaska’s vast coastline is home to approximately 90% of the world’s sea otters. These adorable marine mammals are known to carry and use rocks to crack open certain prey like crabs, clams and mussels to eat while floating in the water. Sea otters also prey on sea urchins, octopus, fish and other small invertebrates.
Unlike most marine mammals, sea otters are primarily insulated by fur, not blubber. They have the densest fur in the animal kingdom, which led to them being hunted for their thick coat. Hunting, combined with other factors, led to the species extirpation from Southeast Alaska. Sea otters were reintroduced to the region in the 1960s.
Even though much work has been done to help these marine mammals, there are still some otterly wrong tails circulating out there. Join us as we crack into the truth and learn five awww-some facts about sea otters!
1. Fact: Northern sea otters are one of three subspecies of sea otter.
While sea otters (Enhydra lutris) are one species, there are three recognized subspecies. Each subspecies lives in a different region, is a different size and even uses different tools. The Asian sea otter’s (E. l. lutris) range is along Russia and Japan’s coastlines, and it is the largest of the three subspecies.
There are two subspecies living in the United States. One is the southern sea otter (E. l. nereis) — also called California sea otters — which lives in waters along the California coastline. This subspecies is the smallest of the three and is the smallest marine mammal in North America! Females weigh up to 50 pounds and males reach up to 70 pounds.
Northern sea otters (E. l. kenyoni) are the other subspecies in the U.S. and are found in Alaska, British Columbia and Washington. Within Alaska, specifically, many live in the waters surrounding Glacier Bay National Park, Kenai Fjords National Park, the Aleutian Islands, Southeast Alaska and Kodiak National Wildlife Refuge. Depending on where they live, the Alaskan northern sea otter subspecies is divided further, which leads us into Myth number 2...
2. Fact: There are three sub-populations, or stocks, of northern sea otters in Alaska.
The Southeast stock of northern sea otters live in the coastal waters of Southeast Alaska; Southcentral stock is located from west of Glacier Bay National Park to the eastern edge of Cook Inlet; and the Southwest stock live in the waters surrounding Aleutian Island, Kodiak Island and the Alaska Peninsula.
3. Fact: One stock of sea otters is listed under the Endangered Species Act.
Overall, the Southwest Alaska stock has declined by more than 50% since the mid-1980s and was listed as threatened in 2005. Predation by killer whales is suspected to be the primary cause of the decline, but further research is needed. The most recent 2023 stock assessment report lists the population estimate at 51,935 otters.
4. Fact: Sea otters are an essential keystone species.
A keystone species helps us understand the functionality and health of an ecosystem. Sea otters have a large-scale effect on the areas where they live! In Glacier Bay National Park, the expansion of sea otters into the area indicated a gradual return of a more diverse ecosystem. In other parts of their range, sea otters help control the sea urchin population and enhance seagrass beds, which are important for maintaining other fish and marine life!
5. Fact: Sea otters help restore and protect kelp forests and eelgrass beds that are crucial habitat of many fish species.
By helping to restore and protect kelp forests and eelgrass beds, that are crucial habitat for many fish species, sea otters benefit marine fisheries. Additionally, sea otters do not hunt or prey on finfish such as rockfish, salmon, ling cod or halibut and prefer shallow water habitats.
Overall, sea otters help increase diversity, productivity and resilience of marine ecosystems. They are crucial to the health of their ecosystems and continue to need our help and protection.
You can help sea otters throughout their range by sharing these sea otter fun facts with your friends and family. Always check your seafood and clothing to ensure its sourced sustainably. Plus, don’t forget to join the 2024 Sea Otter Awareness Week, which is happening now through September 28. Events are happening all week long!
Author
Ragen Davey
Ragen Davey received her Master of Science degree in Environmental Chemistry
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