Welcome back SUFB Crew, I hope you all had a great weekend! We wanted to follow up Canadian Thanksgiving by sharing some facts about the sea otter, a marine mammal that we are all thankful for (Listen to the podcast above to hear the 5 fun facts on sea otters). A descendant of the now-extinct B-otter, sea otters inhabit shallow coastal waters in the north Pacific. Historically they ranged from Japan, Russia, and the Aleutian Islands to Alaska, British Columbia, and the west coast of the U.S. Nowadays the majority of sea otters are found off the coast of Alaska, though some have been spotted as far south as Mexico. Coastal communities used to heavily hunt the sea otter for its thick fur, causing a steady decrease in the pacific population. In the early 1900s, sea otter populations reached a record low of only 1,000 – 2,000 individuals. However, since then hunting restrictions have been put in place. Though they remain endangered, sea otters have rebounded significantly. The current population estimates put them at 106,000 globally, with about 3,000 of the coast of California.
Rather than a single trans-Pacific population, there are actually three distinct subspecies of sea otters that exist in the region. The northern sea otter is isolated to the west coast of Canada and Alaska. The southern or California sea otter is (obviously) located in the coastal California waters. Finally, the Russian sea otter has monopolized the western Pacific, off the coast of Asia. All three of these subspecies spend the majority of their life in the water, giving them the marine mammal title. They can dive up to 330-foot depths while foraging for prey, which mostly consists of shellfish and other invertebrates. Because of the unique dexterity they possess in their paws, sea otters can manipulate and crack open clams, mussels, and other bivalves with hard outer shells to get to the meat inside. Which is a good thing, because sea otters need all the food they can get. In order to stay warm in the cold water, these mammals must eat between 25% – 40% of their body weight each day. This is because unlike most marine mammals, sea otters have very little fat. Most of their body heat is retained through their fur, rather than any sort of insulating blubber.
Sea otters are more than just a pretty face wrapped in a warm, waterproof coat. They play a vital role in the kelp forest ecosystems of the north Pacific. About twenty years ago, when sea otters were on the decline, researchers started noticing a decline in kelp numbers as well. After doing some more digging, they found that sea otters had been controlling the sea urchin populations. With less sea otters preying on the urchins, these spiny invertebrates had exploded in number and were eating all of the kelp. Kelp forests, much like any other plant community, help reduce the amount of CO2 in the environment and produce oxygen for the rest of us. Therefore, it’s vital that sea otters continue to reproduce and keep urchin populations in check. Which means a close eye will have to be kept on these otter populations, since females typically only give birth to one pup at a time. Because males are polygamous, they typically do not spend as much if any time raising their pups. The moms are the primary care provides of young otters, nursing them and carrying them on their chest for between three to six months. After this time, the pups are able to forage on their own and go out into the world to feast on urchins and, ultimately, hold hands with its own special sea otter.