Threatened Pinnipeds and Sea Otters
in the Southern California Planning Area

Six species of pinnipeds, seals and sea lions, live in southern California waters. Two of these, the Steller sea lion and Guadalupe fur seal, are listed as threatened under the Endangered Species Act. The California population of the sea otter is also listed as a threatened species.

Steller, or northern sea lions range along the North American coast from Alaska to southern California. Their world population has recently been estimated at approximately 116,000, of which only 2,000 to 3,000 are found in California. Steller sea lions breed on rookery islands from the Pribilof Islands in Alaska south to Año Nuevo Island in central California. Pupping and breeding occur from late May through July. Following the breeding season, animals from the California and Oregon rookeries move northward, some as far as Alaska. Steller sea lions feed on a variety of prey in estuarine and marine waters, including many species of fishes, sharks, squids, octopus, and shrimp. In Alaska, Stellers are also known to prey upon the pups of other seal species.

The Steller population has declined sharply in recent decades, particularly in Alaska, where local decreases of up to 90 percent have occurred. As a result, the species was listed as threatened in 1990. Possible factors contributing to the decline include disease, decreases in prey species, commercial harvests conducted in Alaska before 1973, entanglement and drowning in marine debris and fishing nets, or killing by fishermen. Sixty years ago, Steller sea lions bred on the Channel Islands and were the most common sea lions in southern California. Now, however, Stellers are rare south of Point Conception and have not bred on San Miguel Island, the last southern California rookery, since 1980.

Guadalupe fur seals once ranged from Mexico north at least as far as Point Conception. Like other fur seal species, their numbers were severely reduced by commercial hunting in the nineteenth century, and for many years they were thought to be extinct. The Guadalupe fur seal was listed as threatened in 1985. At present, the species breeds only on Isla de Guadalupe off the coast of Baja California. The population is still small, perhaps numbering as few as 7,000, but is growing. Although the movements of Guadalupe fur seals at sea are unknown, they do venture into California waters. Strandings have been reported from as far north as Sonoma County. Although Guadalupe fur seals are now rare in southern California, evidence from Native American middens suggests that they once were abundant on San Miguel Island. Each year, a few Guadalupe fur seals are sighted in the area, almost all on San Miguel and San Nicolas Islands. Guadalupe fur seals breed in summer, from late May to early August. Females and pups are found around the island through much of the year, when adult males and many juveniles are at sea. Little is known of the diet of Guadalupe fur seals, although it is known that they feed on pelagic squids and fish such as mackerel and sardines.

Sea otters originally inhabited the North Pacific coast in an almost continuous band stretching from Baja California across the Aleutians to northern Japan. There once may have been as many as 300,000 sea otters. By 1911, when sea otters were protected by international treaty, only 13 isolated otter colonies remained; most of these became extinct. From this low point, the species slowly began to recover. Several surviving Alaskan populations reoccupied former habitats. The surviving California population also began recovering from a low of about 50 animals. Beginning in 1965, efforts were made to recolonize former habitats by translocating Alaskan otters to areas in Alaska, British Columbia, Washington, Oregon, and California.

Sea otters now occupy most of their historical range west from Prince William Sound in Alaska to the Russian Kurile Islands. They are also found in southeast Alaska, Vancouver Island, northern Washington, and central and southern California. Recent estimates of the species' total population have ranged as high as 168,000. The California sea otter population was listed as threatened in 1977. The range in central California now stretches from about Point Año Nuevo south to the Santa Maria River. The population is growing and currently numbers more then 2.000

In 1987, the Fish and Wildlife Service began translocating sea otters from central California to San Nicolas Island in southern California. By 1991, 139 sea otters had been translocated, of which only 10-15 were still present at the island. The remainder were back on the mainland coast, dead, or missing. Twenty-one pups had been born at San Nicolas. Although this is a decline of almost 90 percent, similar declines have occurred in the first year or two following all other translocations, most of which eventually succeeded.

Sea otters breed and pup throughout the year, and there appears to be one or more peaks in most parts of the range. Females typically give birth to a single pup, and pups remain with their mothers for 4 to 8 months. In California, otters live in waters less than 65 feet deep and rarely move more than a mile offshore. California sea otters feed almost entirely on large invertebrates, including abalones, crabs, sea urchins, clams, snails, mussels, octopus, barnacles, scallops, sea stars, chitons, and worms. Sea otters in California rarely eat fish.