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California Sea Otters—2007 Survey Count Reaches New High

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map of California showing sea-otter survey area
Above: The spring 2007 California sea-otter survey covered about 375 mi of the California coast, from Point San Pedro in the north to Rincon Point in the south. [larger version]

Observers led by scientists from the U.S. Geological Survey (USGS) counted a total of 3,026 California sea otters during the 2007 spring survey, marking a record high and a 12.4-percent increase over the 2006 count of 2,692. The previous high was 2,825 sea otters in spring 2004.

"The favorable viewing conditions—the best we've had in years during our spring surveys—likely contributed to the encouraging count," said survey organizer Brian Hatfield, a USGS biologist stationed in San Simeon, California.

Also rising slightly is the latest 3-year running average—the average of the totals from the spring counts of 2005, 2006, and 2007—which is up 2.4 percent over the previous average, to 2,818 sea otters. To assess overall population trends, 3-year running averages of spring counts are used to reduce the influence of anomalously high or low counts during any particular year, as recommended by the U.S. Fish and Wildlife Service (USFWS)'s Southern Sea Otter Recovery Plan. "We are guardedly optimistic about the slight increase in this latest 3-year running average," said Lilian Carswell of USFWS, "although the population remains a considerable distance from the delisting threshold. For southern sea otters to be considered for delisting, the 3-year running averages would have to exceed 3,090 for 3 continuous years."

graph showing the number of southern sea otters counted during spring surveys
Above: Number of southern sea otters counted during spring surveys.

graph showing number of southern sea otters counted during spring surveys, plotted as 3-year running averages
Above: Number of southern sea otters counted during spring surveys, plotted as 3-year running averages. (For example, values for 2006 are averages of the 2005, 2006 , and 2007 counts.)

"While a high count is always better news than a low count, these counts have varied quite a lot in recent years," said USGS scientist Jim Estes, whose sea-otter expertise spans more than 3 decades. He pointed out that last year's count was on the low side, for example, and noted that "We cannot infer much about the population until there has been a sustained trend."

Several segments of the coast surveyed this spring showed significant increases in the adult and subadult group of sea otters called independents. The greatest increase was 135 more independents this year for Monterey Bay. At the south end of the survey area, 39 independents were spotted east of Gaviota and 29 in the Naples Reef area, approximately 7 km west of Coal Oil Point (50 km east of Point Conception). By comparison, none were spotted east of Gaviota during the spring 2005 count, and only one in spring 2006.

The spring 2007 California sea-otter survey was conducted May 2-17 and covered about 375 mi of California coast, from Point San Pedro in the north to Rincon Point in the south. Overall viewing conditions were more favorable than those during the spring 2006 survey. The annual spring survey is a cooperative effort of the USGS, the California Department of Fish and Game's Marine Wildlife Veterinary Care and Research Center, the Monterey Bay Aquarium, and many experienced and dedicated volunteers. The information gathered from spring surveys is used by Federal and State wildlife agencies in making management decisions about this small sea mammal.

For additional information about the 2007 California sea-otter survey, visit URL http://www.werc.usgs.gov/otters/ca-surveyspr2007.htm.

Related Sound Waves Stories
California Sea-Otter Numbers Dip Again in 2006, But Overall Population Trend Remains Up
August 2006
California Sea Otters—2005 Survey Numbers Dip, But Overall Population Trend Remains Positive
August 2005
New USGS Video Available Online: "Precipice of Survival: The Southern Sea Otter"
October 2004
California Sea-Otter Numbers Climb for Second Consecutive Year
July 2004
Collapsing Populations of Marine Mammals the North Pacific's Whaling Legacy?
October 2003
California Sea Otter Numbers Are Up for the 2003 Census
July 2003
California Sea Otter Numbers Slide for Second Straight Year
July 2002
Congressional Briefing on California Sea Otter Research
March 2002
What's Wrong with the California Sea Otter?
February 2002

Related Web Sites
Spring 2007 Mainland California Sea Otter Survey Results
USGS (U.S. Geological Survey)

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Tar Seeps in the Santa Barbara Channel

California Sea Otter Count Reaches New High

Outreach Upcoming! "A Tale of Two Kelp Forests" Public Lecture

MIT Students Tour USGS Woods Hole Science Center

Coastal-Hazards Research Featured in First USGS Podcast

Meetings Scientists Meet Managers at Coastal Zone 2007

Airborne-Lidar Technology and Applications Workshop

Awards USGS Hydrologist Honored for Outstanding Community Outreach

Staff Upcoming! New Vice President of Pacific Section SEPM Helps Plan Fall Field Trips


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