Sea otters are a beloved marine mammal, native to the coasts of the northern and eastern North Pacific Ocean. Otters were hunted extensively for their fur during the 18th-20th centuries, leading to a population fall and reduction of their historic range. A subsequent international ban on hunting, combined with conservation efforts and reintroduction programs have contributed to numbers rebounding, and the species now occupies about two-thirds of its former range. Although considered a conservation success, sea otters remain vulnerable to human activities, disease, and changing climates, and are listed as Special Concern by both SARA and COSEWIC.
Sea otters are a classic example of a keystone species, having a profound effect on their ecosystem. By preying on benthic herbivores such as sea urchins, they help to maintain grazing in check and enable kelp forests to thrive. Before conservation efforts were put in place, a decline in sea otters in British Columbia enabled urchin populations to grow unchecked, and kelp forests along the rocky coastlines died off. The loss of habitat and nutrients provided by kelp can lead to profound cascade effects throughout the marine ecosystem.