After taking an experimental bite and finding a mouthful of fur instead of blubber, the shark usually lets go and moves on. Eelgrass is one of the rarest habitats in California, with only about 11,000 to 15,000 acres estimated to remain, according to the National Oceanic and Atmospheric Administration. Related Articles Otters can provide several ecological benefits to local estuaries and could help the restoration of eelgrass beds that are vital to marine animals and migratory birds, researchers say. Since the 1990s, the southwestern stock of Alaskan sea otters has experienced a dramatic (up to 70% population) decline, most likely due to increased predation by killer whales. The southern sea otter ( Enhydra lutris nereis) is descended from one of these remnant colonies that survived along the Big Sur coastline of central California, and contained perhaps as few as 50 individuals at the beginning of the 20th century (Riedman and Estes 1990). “To maintain their core temperature, they have to eat 25% of their weight every day to stay alive,” Hughes said. “Over the longer term, it’s not just sea otter numbers we’re after, but the restoration of ecological relationships,” said Carswell. A separate ground-based survey of the sea otter population at San Nicolas Island was completed earlier (April 15–18). It’s not a long-term solution. Only 13 remnant sea otter colonies existed from Russia to Mexico when the International Fur Seal Treaty, which banned the hunting of sea otters and fur seals, was established in 1911. Most species are entirely dependent on aquatic habitats for food. So it’s not like you can throw sea otters into the bay right now and it wouldn’t be without any risk to the sea otter.”. 1). Young great white sharks are usually the biting culprits, mistaking the otters floating on the surface for more blubbery prey such as seals or sea lions, Hughes said. By 1976 the population contained an estimated 1,789 individuals, but then declined to 1,443 by 1979 and to 1,372 by 1984. This has been made possible by legal protection — in 1977 sea otters became protected under the Endangered Species Act — and by the work of nongovernmental organizations to support growing the population of … Lemur theft suspect ordered to stay away from San Francisco zoo The Alaskan sea otter population numbered more than 100,000 in the 1980s. California sea otter population reaches record…, Click to share on Facebook (Opens in new window), Click to share on Twitter (Opens in new window), Click to email this to a friend (Opens in new window), Stanford pulls plug on the return of freshmen and sophomores to campus, California sea otter population reaches record high number, | Natural resources and environment reporter. Sea otters along the mainland were surveyed from Pillar Point in San Mateo County in the north, to Rincon Point in the south at the Santa Barbara/Ventura County line (fig. Post was not sent - check your email addresses! The decimation of North Coast kelp forests by urchins in recent years following significant losses of the predatory sea stars to wasting disease is an example of what can occur if populations are kept unchecked. A project in the 1970s to transfer some from the Aleutian Islands to southeastern Alaska succeeded. Otters could potentially provide that same function in San Francisco Bay.”. While superficial, these bites can often be fatal have a significant impact on limiting the population size as well as the range of the otters, Harris said. Historical evidence including archaeological finds supports that the bay once hosted a large population of otters prior to the mid-19th century, the study states. California sea otters were feared to be extinct until a small number, about 50, were discovered in remote coves off Big Sur in the 1930s. All Access Digital offer for just 99 cents! Once thought extinct, a small group of otters survived with their progeny making up the existing population. All Access Digital offer for just 99 cents! But an effort in the 1980s to move them to San Nicolas Island off the Southern California coast was considered a failure because many swam back to the mainland or died. California’s southern sea otter has been listed as a threatened species under the Endangered Species Act since 1977. The new study, published in “PeerJ: the Journal of Life and Environmental Sciences” in December, found that San Francisco Bay could support about 6,600 southern otters. However, their numbers at San Nicolas are finally growing and now near 100. The range-wide index, defined as the 3-year average of combined counts from the mainland range and San Nicolas Island, was 2,962, a decrease of 166 sea otters from the index for the previous year. “There’s not much there, just fur and bones. It has rebounded to around 3,000, still far below the estimated pre-fur trade population of 16,000. Tomales Bay, Humboldt Bay, San Francisco Bay, San Diego Bay and Mission Bay support more than 80% of the known eelgrass in the state, according to the agency. and about normal in the southern half. While Sawyer said he supports the recovery of threatened species such as the otter, the complexities and challenges that San Francisco Bay poses should be very thoroughly vetted and studied before any formal proposal moves ahead. Although they are most strongly associated with rocky substrates, sea otters can also live in areas where the sea floor consists primarily of mud, sand, or silt. By 1976 the population contained an estimated 1,789 individuals, but then declined to 1,443 by 1979 and to 1,372 by 1984. And recent research in Elkhorn Slough in Monterey County has found otters help boost sea grass, also a key home for fish, because they eat crabs. Sea otters live in coastal waters 15 to 23 metres (50 to 75 ft) deep, and usually stay within a kilometre (⅔ mi) of the shore. River otters (genus Lutra) inhabit all types of inland waterways, as well as estuaries and marine coves. With conservation efforts, California's sea otter population has slowly grown to around 3,000. One reason there may have been so many more sea urchins in recent years, scientists say, is because of a disease that killed huge numbers of sea stars, or starfish, along the West Coast. 41 years later and counting, their conservation status remains unchanged and their future uncertain. Listed in California on January 14 th 1977, the Southern Sea Otter, also known as the California Sea Otter, began to decline after almost 150 years of hunting for its fur. That said, there are still some troubling trends. Historically there were about 16,000 southern sea otters, commonly known as California sea otters, that lived from Oregon to Baja, Mexico. This is a challenging task due to year to year environmental variability and other external factors that may provide conflicting information. and about normal in the southern half. 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