John Ugoretz, US Navy biologist on San Nicolas Island, discusses how the island’s kelp forests provide an ideal habitat for sea otters and many other aquatic animals.
Kelp forests are found around the world. They are formed by a variety of marine algae. In Southern California, kelp forests occur in most nearshore rocky habitats. They are mostly made up of brown algae, commonly known as giant kelp. Giant kelp can grow as much as two feet per day in water depths from about five to 70 feet depending on the ocean depth and clarity of the water.
Because of its remote location, San Nicolas Island has clearer water than along the mainland coast, and much of the ocean around the island is the ideal depth for kelp growth. San Nicolas is home to one of the largest kelp forests of all the Channel Islands.
Kelp forests create a vertical habitat and canopy cover, similar to forests on the mainland, and provide shelter for a wide variety of fish. Common San Nicolas Island kelp forest fishes include California sheephead, lingcod, Garibaldi, kelp bass, señorita, a variety of surf perch, and other types of rockfish.
The kelp forest is also home to a variety of marine invertebrates including spiny lobster, crabs, sea urchins, abalone and many others. San Nicolas Island has greater populations of many of these fish and invertebrates than most other locations in Southern California.
Sea otters feed, sleep, and spend the majority of their lives in or near kelp forest habitats. They use the kelp canopy as shelter and will even wrap themselves in kelp while resting on the surface. Otters feed on many of the invertebrates found in the kelp, especially snails, urchins, and crabs. Sea urchins are so abundant around San Nicolas Island that they make up more than one quarter of the diet of island sea otters
Otters on San Nicolas have been found to be healthier than those near the California mainland coast. The abundant kelp and associated animals around San Nicolas provide an ideal location for sea otters to thrive.