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Congressional Briefing on California Sea Otter Research
At the request of Congressman Sam Farr (D-17-CA), the Western Ecological Research Center (WERC) hosted a briefing in Sacramento on January 31, 2002, on the status of sea-otter research whose funding he initiated. The following were present at the briefing: Reed Addis, District Director for Congressman Farr; Debbie Maxwell, Center Director, USGS, WERC; Karen Phillips, Research Manager, USGS, WERC; Jim Estes, Research Scientist, USGS, WERC; Chris Brand, Research Manager, USGS, National Wildlife Health Center (NWHC); Nancy Thomas, Pathologist, USGS, NWHC; Dave Jessup, Veterinarian, California Department of Fish and Game (CDFG); and Greg Sanders, Sea Otter Coordinator, U.S. Fish and Wildlife Service. Jim Estes briefed the Congressman's aide on research currently underway at WERC's Santa Cruz Field Station to discover reasons why the threatened California sea-otter population has experienced several periods of recent decline and an overall slower-than-expected recovery. Research is looking at both the dead and live population for answers. As part of the sea-otter-monitoring program, beach-cast carcasses have been recovered and analyzed for trends in distribution, abundance, age and sex composition, and cause of death. In 2001, a comprehensive analysis of this information was completed for all carcasses recovered from 1968 to 1999. The analysis showed that mortality, not reproduction, is the primary driver of change in population abundance. Studies of the living population were initiated in 2001 in an effort to characterize key aspects of demography, behavior, and physiology in the California sea otter and to determine why so many animals are dying. This study is hoped to be a 5-year effort. Nancy Thomas discussed the necropsy program of NWHC. The principal goals of this program are to identify and monitor the major causes of death in sea otters, establish the relative frequency of different causes of death, and determine the impact of diseases and other causes of death on population recovery. Necropsies have been conducted on fresh, beach-cast sea-otter carcasses since 1992, initially at NWHC. Since 1998, 25 percent of the necropsies have been conducted at NWHC, and 75 percent at the CDFG Marine Wildlife Veterinary Care and Research Center. Causes of death among necropsied animals have primarily been attributed to various infectious diseases (more than 40 percent), and this rate of disease mortality has remained relatively consistent over time and for prime-aged adults. In addition, Nancy reviewed other projects conducted jointly with the CDFG, including assessment of the impacts of disease and other mortality factors on the population, and future joint studies of contaminants and epizootiology. Dave Jessup discussed various sea-otter research projects being conducted by the CDFG, including current joint projects with NWHC and the University of California, Davis (UCD), such as the necropsy collaboration and development of a joint database. The CDFG is also participating with WERC and UCD in studies of the living population. Various measurements are taken from each individual at the time of capture, including blood samples, swabs, and other biomedical samples for baseline health assessment and genetic studies and to determine immunologic function, exposure to selected infectious diseases, and selected contaminants. Dave also mentioned additional projects underway at CDFG and in collaboration with UCD, including investigations into pathogen pollution, contaminants in prey, and immunosuppressive factors.
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in this issue:
Radio Interview Explores African Dust Florida Coastal Storm Defenses Environmental Academy Web Site Congressional Briefing—Sea Otter Research John Hughes Clarke—"Imaging Water Mass Variability" |
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U. S. Department of the Interior | U.S. Geological Survey
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