Otters of the San Juan Islands

Otters are a welcome sight around the San Juan Islands

When thinking about the otters on San Juan Island, the first thing that comes to mind are the cute, cuddly sea otters. However, there are actually two different species of otters found in the waters of San Juan Island.

Sea otters are the smallest of the marine mammals found on the West Coast, but don’t let their size fool you: some male sea otters can weigh up to 99 lbs. Sea otters rely on their thick fur to keep them warm while out to sea. With 150,000 strands of hair per square centimeter, sea otters have the densest fur in the world and are always cleaning themselves to keep their coats ready for the cold waters. Though sea otters come onto land occasionally, they are adapted to spend a majority of their lives in the sea, even giving birth while floating in the water.

Extensive sea otter trapping began in the 1740s which severely reduced their wild population down to only one or two thousand. Previously, sea otters numbered in the hundreds of thousands. Noting the drastic impact of over-trapping, the governments of Japan, Russia, Great Britain/Canada, and the United States signed the North Pacific Fur Seal Convention of 1911. The convention outlawed open-water hunting practices and began the conservation of marine mammals like the fur seal and sea otter. This convention became the first international treaty promoting wildlife preservation.

Many of the otters found on the island are in fact the North American river otter. Though sea otters were once common in the San Juans, today their range is to the north in the Canadian Gulf Islands.

Unlike its seafaring cousin, the North American river otter is adapted more to terrestrial life. River otters can be found in a multitude of aquatic locations, including lakes, wetlands, and even marine habitats. Smaller than the sea otter, river otter males typically weigh around 25 lbs, and females weigh around 18 lbs. River otters also differ from sea otters in how they swim. Sea otters typically float on their backs while river otters swim primarily on their front. The North American river otter is a very social creature, often forming various groupings. A mother and her kits may form one such group, whereas some male river otter groups can reach around 20 members.

Like sea otters, river otter populations also declined with fur trading. However, because they have been slowly reintroduced after fur trading management and water quality standards began, populations have improved. Starting in 1976, 4,000 river otters have been reintroduced in the United States and Canada. Currently, 29 U.S. states and nearly all Canadian provinces hold steady river otter populations. If populations continue to rise, the future looks bright for the otters of San Juan Island.