In the case of otters, their eating habits help to control the population of crabs, sea urchins and other invertebrates. Why haven’t the hummingbirds flown south for the winter? With conservation efforts, California's sea otter population has slowly grown to around 3,000. 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. Why Are Sea Otters Important? Conception. The otters are listed as a threatened species under the Endangered Species Act. So using a variety of established study methods — radio tracking, veterinary exams, genetic analysis, diet observations — this collaborative group of scientists hopes to uncover new knowledge about this population of California’s iconic sea otters — a population that hasn’t been extensively studied for … A project in the 1970s to transfer some from the Aleutian Islands to southeastern Alaska succeeded. Once thought extinct, a small group of otters survived with their progeny making up the existing population. They help boost kelp beds, which provide a home to fish and other species, for example, because they eat urchins, which eat kelp. Most species are entirely dependent on aquatic habitats for food. The Otter Project produces an annual southern sea otter status report to characterize the current status of the population. “Just because of the massive size of San Francisco Bay and its existing habitat, it could still support a thriving sea otter population,” said Hughes, an assistant professor of biology at Sonoma State University. Why haven’t the hummingbirds flown south for the winter? 1). Southern sea otters (Enhydra lutris nereis), also known as California sea otters, were listed as threatened in 1977 under the Endangered Species Act. Sea otter population growth has stalled in recent years and many hurdles for full population … River otters (genus Lutra) inhabit all types of inland waterways, as well as estuaries and marine coves. 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. A century ago, by the unscientific estimate of crab fishermen along the central coast of California, more than 100,000 sea otters (Enhydra lutris nereis) populated the waters between Monterey Bay and Santa Barbara, a distance of about 250 miles. “That’s a lot.”. The sluggish recovery of the southern sea otter of California, a threatened population on the Endangered Species list, appears to have stalled once again. 41 years later and counting, their conservation status remains unchanged and their future uncertain. 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. 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. Scientists also believe that sea otters could be conservation allies, with their potential to help restore other polluted estuaries in California. Sea otter population growth has stalled in recent years and many hurdles for full population recovery remain. This year, for the first time since population goals were set in the 1980s, researchers have counted more than 3,000 sea otters and pups on California's central coast. Other estuaries such as those in Drakes Estero, Tomales Bay, Bodega Bay and Humboldt Bay could provide further habitat, the study states. 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. So using a variety of established study methods — radio tracking, veterinary exams, genetic analysis, diet observations — this collaborative group of scientists hopes to uncover new knowledge about this population of California’s iconic sea otters — a population … Sea otters live in shallow coastal waters off the northern Pacific. 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. “It would change the game in terms of how we look at sea otter … Giant otters (genus Pteronura) are found mainly in slow-moving rivers and creeks within forests, swamps, and marshes. 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). In fact, the otter population is likely at its highest level in at least 100 years, Tinker said. Extensive study would be required before any formal reestablishment proposal moves ahead, Hughes and Harris said. Having more sea urchins to eat has likely helped young otters survive because the urchins are nutritious and abundant. 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 … “And that’s good news because sea otters bring ecological benefits.”. Historically there were about 16,000 southern sea otters, commonly known as California sea otters, that lived from Oregon to Baja, Mexico. We’re highlighting that as kind of a big mistake,” Hughes said. 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. San Francisco Bay could triple threatened otter…, 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, San Francisco Bay could triple threatened otter population, study says, Lemur theft suspect ordered to stay away from San Francisco zoo, On National Bird Day, Trump administration rolls back more wild bird protections, Gull causes power outage for nearly 6,000 Santa Cruz residents. 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. “To maintain their core temperature, they have to eat 25% of their weight every day to stay alive,” Hughes said. “Eelgrass habitat is a critical nursery for small finfish and invertebrates,” Harris said. Southern sea otters, also called California sea otters, live in waters along the California coastline, ranging from San Mateo County in the north to Santa Barbara County in the south. For Hughes, the study is meant to provide decision-makers updated information and how they plan to use it is up to them. Their northern range is limited by ice, as sea otters can survive amidst drift ice but not land-fast ice By establishing new populations in estuaries, conservation agencies could expedite what could potentially take decades or even centuries if left to natural processes, Hughes said. “How long is that going to last? Today, there are about 3,000 otters found in central and southern California waters. 1). Population Historically, sea otters numbered between 150,000 and 300,000 animals throughout the Pacific Rim. A standardized method to survey sea otters (Enhydra lutris nereis) was developed by WERC scientists and put into use in 1982 in California. and about normal in the southern half. Overall viewing conditions this year were very good, better than those encountered during the 2018 spring census (View Score = 3.0 this year compared to 2.4 last year, where 0=poor, 1=fair, 2=good, 3=very good, and 4=excellent). The historic population of California sea otters was estimated at 16,000 before the fur trade decimated the population, leading to their assumed extinction. San Francisco Bay could act as a haven for California’s threatened southern sea otters and could potentially triple the existing population, according to a new study led by Sonoma State University. Today, the otters would face modern dangers of heavy vessel and boat traffic, hazardous waste, sewage spills, oil spills and a significantly larger human presence. Otters can be highly susceptible to pathogens and human interaction has been shown to have a detrimental impact on otters, especially pregnant females that constantly live on the “metabolic edge,” Harris said. 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. 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. Sorry, your blog cannot share posts by email. Population abundance of the California sea otter has steadily increased through the twentieth century, except for two periods. “… We’re just highlighting that there is a lot of benefits and managers should consider estuaries in the future should they want to expand the range.”, Get Morning Report and other email newsletters. This triangle-shaped patch of ocean stretching between Big Sur and Bodega Bay has one of the highest concentrations of great white sharks. According to the Otter Foundation, the California sea otter population declined from July 2008 to July 2011. California’s southern sea otter has been listed as a threatened species under the Endangered Species Act since 1977. Of the cases where trauma is determined as the cause of death, shark bites account for about half of them, Harris said. In 1938, the population in California was only about 50 animals. A CDFW scientist using a telescope to search for sea otters. California sea otters are found off the coast of central California, from Half Moon Bay to Pt. At some point, there may be efforts to move some otters to new locations, like San Francisco Bay or farther up the California coast toward Oregon, he said. Tinker said no scientists are calling for white sharks to be killed to protect the otters because that would cause other environmental problems. Sea otters are what’s known as a keystone species in that an ecosystem would become drastically changed if they were no longer present. The textbook example of this is otters controlling sea urchin populations, which in turns reduces the urchins’ consumption of kelp forests. No one knows for sure why shark bites have become the chief source of mortality for California sea otters. “It is a two-way street,” Tinker says. Sea slugs eat the algae that builds up on sea grass from human runoff of fertilizer and other nutrients. The ultimate goal of southern sea otter recovery is to reestablish ecological relationships in the ecosystems where sea otters and other nearshore species coevolved. from shore. With conservation efforts, California's sea otter population has slowly grown to around 3,000. Enhydra lutris was placed under the Endangered Species Act (ESA) in 1973 and is now listed on CITES Appendix I and II. 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. Otters are usually found no more than a few hundred meters from water. Otters are a keystone species, and they affect all levels of the food chain. The southern sea otter (Enhydra lutris nereis) population at San Nicolas Island, California, has been monitored annually since the translocation of 140 sea otters to the island was completed in 1990. Related Articles The state has been monitoring sea otters for more than 50 years and typically finds between 460 to 490 dead sea otters each year. 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. This is a challenging task due to year to year environmental variability and other external factors that may provide conflicting information. 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. Gull causes power outage for nearly 6,000 Santa Cruz residents Prior to European settlers, the otters in the bay were hunted by Native American tribes, but the waters themselves were relatively undisturbed, Hughes said. Decadelong restoration of Año Nuevo Island deemed a success, ‘Fossil water’ may be vanishing from California, Dungeness crab season can finally get started; fleets, wholesalers agree on price, Rare snowfall blankets Spain, closes Madrid airport. The populations of those animals soared, particularly off Año Nuevo and Piedras Blancas near Hearst Castle. Other attempts to move otters have met with mixed results. And for the first time, the otter numbers have exceeded 3,090, the total that the U.S. In this photo taken Monday, March 26, 2018, a sea otter is seen at the Monterey Bay Aquarium in Monterey, Calif. California sea otters, once … Since 1982, a standardized method has been deployed to survey the sea otter population in California. Sea otters were presumed extinct in California after the 19th century fur trade years, but were rediscovered in the 1930s by the public, when as few as 50 animals were documented persisting in nearshore areas off the coast of Big Sur. The 2019 census of southern sea otters (Enhydra lutris nereis), also known as California sea otters, was conducted from early May to early July along the mainland coast of central California and in April at San Nicolas Island in southern California. “There’s not much there, just fur and bones. He also has worked as managing editor of the Science team at KQED, the PBS and NPR station in San Francisco, and has taught science writing at UC Berkeley and UC Santa Cruz. “The work that Hughes has done in Elkhorn Slough suggests that otters can play this ecosystem service role by helping to reestablish a healthy environment through their foraging pressure. Two sea otter subspecies occur in the United States, the southern sea otter (Enhydra lutris nereis) and the northern sea otter (E.l. kenyoni). “They’re fascinating, high-maintenance animals and they’re incredibly powerful,” he said. They were protected by the Endangered Species Act in 1977 and began a slow comeback. Moving otters would likely be controversial, particularly among fishermen, since they eat abalone, crabs and urchins, all of which are fished commercially. In the U.S., there are two distinct sea otter subspecies, the Northern sea otter and the Southern (or California) sea otter. Estimates suggest a California population of approximately 2700 individuals. By 1976 the population contained an estimated 1,789 individuals, but then declined to 1,443 by 1979 and to 1,372 by 1984. The annual survey, conducted by the USGS, U.S. 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. 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.”. Reduced range and population size, vulnerability to oil spills, and oil spill risk from coastal tanker traffic were the primary reasons for listing. “However, there are a bunch of risks and we highlight that in the paper. 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. 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. With less algae, the sea grass prospers, providing a nursery for young fish. 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. Michael Harris, a California Department of Fish and Wildlife senior environmental scientist who has studied sea otters for nearly 30 years, said otters have had difficulty expanding beyond their range for various reasons, but great white sharks are high on the list. Using existing studies and modeling of sea otter growth, the researchers concluded that the San Francisco Bay could support about 6,600 sea otters, more than twice the current estimated population of 3,000.