The spring 1999 survey of 2,090 California sea otters indicates the population has declined overall by 1.14 percent since the 1998 spring survey, which revealed that there were a total of 2,114. There was, however, a disconcerting decline in the group categorized as independents, which includes all adults and subadults. That category of sea otters declined nearly 5 percent, from 1,955 in spring 1998 to 1,858 in spring 1999.
Spring surveys of California sea otters have shown a steady decrease from a high of 2,377 sea otters counted in 1995. The surveys, conducted cooperatively by scientists of the U.S. Geological Survey, California Department of Fish and Game and Monterey Bay Aquarium with the help of experienced volunteers, cover about 375 miles of California coast, from Half Moon Bay south to Santa Barbara.
"This continuing pattern of decline is of grave concern, especially given our lack of understanding of the cause. The information we gather from these surveys will be used by federal and state wildlife agencies in making important decisions about the management of this sea mammal," said Jim Estes, a USGS scientist with the Western Ecological Research Center in Santa Cruz.
Scientists do not understand why the California sea otter is declining, said Estes. Sea otter deaths, as indicated from beach-cast carcasses, have increased over the same time period that the survey numbers have declined. Additionally, during 1998, 213 stranded sea otters were reported, the highest number ever recorded.
Just what factors are responsible for the increase in deaths is
unclear. Disease, contaminants, starvation and entanglement or
entrapment in coastal fishing gear may be contributi
Contact: Gloria Maender
United States Geological Survey