CREATURE FEATURE: Sea Otters (Enhydra lutris)
Native to the coastal waters of the North Pacific Ocean, sea otters are the heaviest members of the weasel family. They prefer to live along nearshore environments where they can dive down to forage and largely feed on sea urchins, mollusks, and crustaceans. Sea otters are one of the few mammal species that have been observed using “tools”, with rocks often used to dislodge prey and open shells.
Sea otters usually grow up to 5 feet (1.5 meters) in length and can weigh up to 100 pounds (50 kilograms). They have a streamlined body and a slightly flattened tail, with dense thick fur that comes in various shades of brown. While they have small front paws, their large hind limbs are like flippers and designed for swimming, rather than walking on land. They can often be seen floating on their back at the water’s surface or creating rafts of anywhere from 3 to 100+ individuals.
Despite their preference for cold waters, sea otters have little body fat to keep themselves warm and rely on their thick fur for insulation. They also have a high metabolic rate and eat a lot to maintain their body heat. Sea otters give birth to a single pup at any one time, with newborns usually traveling on their mother’s belly.
A friendly sea otter waves to a passing kayaker!
The Reintroduction of a Keystone Species
Across much of their range, sea otters are keystone species and play an important role in controlling sea urchin populations, which can otherwise have a devastating impact on kelp forests. But as several of its prey species are also important food sources for humans, thriving sea otter populations can have negative economic and cultural impacts.
Between 1741 and 1911, sea otters were hunted extensively for their fur and their population fell to between 1,000 and 2,000 individuals. This led to an international ban on hunting and conservation efforts that included reintroduction programs into previously populated waters. By the early 20th century, sea otters no longer existed in Canada, that was until they were successfully re-introduced off the west coast of Vancouver Island between 1969 and 1979.
Since that time, they have slowly repopulated along the coastline of British Columbia and their recovery is considered a success story of marine conservation. Today, sea otters can be found in exposed coastal areas and kelp beds on the west coast of Vancouver Island, from Clayoquot Sound to Cape Scott. They can also be found along the north coast of Vancouver Island and around island groups in Queen Charlotte Strait.
A small detail from a carved wooden totem pole showing two sea otters holding a large clam.
The Importance of Sea Otters to First Nations People
For some First Nations people, the flourishing sea otter population has driven other important food sources to scarcity, including crabs, clams, and abalone that were once abundant along the British Columbian coastline. For at least 10,000 years prior to colonization, British Columbia’s First Nations people harvested shellfish and hunted sea otters in a sustainable manner.
As a result, the number of otters in the region’s coastal waters never reached such high densities that they began searching for new things to eat, which is what is being observed today. As the sea otters exhaust their food sources, they are moving into new territory and beginning to prey more heavily on fish.
Sea otter furs were also culturally significant for the Nuu-chah-nulth First Nation as a status symbol to distinguish chiefs. Head chiefs of the Haida were known to line their beds with otter furs while clam gardens (watery raised beds) were established along the coastline so shellfish could be cultivated without predatory otters.
A raft of sea otters rest in bull kelp.
Sea Otters and Commercial Fisheries
The reintroduction of sea otters has also had a significant impact on sea urchin populations, which were previously devastating kelp forests. This resulted in “urchin barrens”, areas of the seafloor that are devoid of plant life and just covered in urchins. While this was great for sea urchin fisheries, which boomed prior to sea otter reintroduction, it was devastating for marine species that rely on kelp forests for protection and as nurseries.
Ravenous sea otters have since re-established this balance, although the negative impact on commercial fisheries harvesting urchins has been estimated at $7 million per year. While recovering kelp forests are projected to offset these losses due to their carbon sequestration, it is evident the impact of sea otter recovery has affected communities in British Columbia inequitably.