This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Populations of southern, or California, sea otters (Enhydra lutris nereis) have declined for the second year in a row, including a dramatic drop in births, according to new numbers released by the U.S. Geological Survey (USGS). At the same time, the money necessary to study and help save the sea otters could soon evaporate amidst California's budget crisis.
The USGS monitors sea otter populations that live off the coast of central California every year and then averages the new count with tallies from the previous two years. This helps compensate for any over- or undercountingdue to weather or other unfavorable conditions that the survey might encounter in any given year. The newest average count for 2010 shows 2,711 sea otters, a 3.6 percent drop from last year's average. More alarming, the number of pups has dropped 11 percent, to 2003 levels. Meanwhile, the otters' range along the California coastline has shrunk by 50 kilometers, for reasons that have not yet been discovered.
Although no clear reason for the decline or range reduction is known, the USGS points to several possible contributing factors: "Our data suggest that breeding-age females are dying in higher than usual numbers from multiple causes, including infectious disease, toxin-exposure, heart failure, malnutrition and shark attacks," Tim Tinker, lead scientist for the USGS survey project, said in a prepared statement. Tinker is an adjunct professor of ecology and evolutionary biology at the University of California, Santa Cruz (UCSC).
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There are some questions about the new count. The Otter Project, based in Monterey, Calif., points out that the actual 2010 otter total was 2,719, slightly up from last year when removed from the three-year average. But the Project doesn't think that is a sign the animals are healthy: "The count is ever so slightly up—a good sign. The pup count is sharply down—a bad sign. And year-to-date strandings are sharply up—another bad sign," Otter Project founder Steve Shimek told the Monterey County Herald.
Tinker is leading a new study at UCSC to learn more about what factors can harm sea otter health, but funding could soon be hard to come by. Some of the money available to study sea otters and help save them comes from California's Sea Otter Fund, which pays for much of the research on the species and is voluntarily funded by California taxpayer contributions. This year's donations are $31,000 short of target, leaving the fund vulnerable to termination by the state tax board. Board spokesman John Barrett told The Sacramento Bee that the fund likely will be eliminated this year if donations do not increase immediately.
California sea otters have been protected under the Endangered Species Act since 1977. They can only be removed from the endangered species list if the population exceeds 3,090 for three consecutive years.
