About OSPR
Scientific Branch
Sea Otter Research

The Marine Wildlife Veterinary Care and Research Center (MWVCRC) staff have a number of projects related to the recovery of the southern sea otter listed as threatened under the Federal Endangered Species Act (ESA). These projects include:

Sea Otter Pup Survival

The MWVCRC staff is cooperating with the U.C. Davis Wildlife Health Center, United States Geological Survey/Biological Resources  Division (USGS/BRD), and the  Monterey Bay Aquarium (MBA) in a study of the survival of sea  otter pups that are orphaned,  raised in captivity and released and comparison free-ranging animals. This is the PhD thesis work of Krista Hanni and will compare activity budgets, foraging behavior and health parameters as determinates of survival. A separate serosurvey of adult animals is comparing exposure rates to various infectious diseases. A grant from the Oiled Wildlife Care Network (OWCN) and many other sources of funding and staff support this very labor intensive project.

Twice Yearly Sea Otter Counts

The combined efforts of employees of the USGS/BRD, CDFG-MWVCRC, the Monterey Bay Aquarium, Friends of the Sea Otter, U.C. Davis graduate students, and other groups work together to complete the spring 2000 range wide sea otter count done twice per year.  The spring 2000 survey of 2,317 California sea otters indicates an overall increase by 10.9 percent since the 1999 spring survey of 2,090 individuals. This is the first overall increase observed since spring 1995, when the threatened population reached its highest number of 2,377 individuals. At the same time more dead sea otters are being found than ever.  The general decline  has spawned a number biomedical research efforts.  For more information on what you can do to help go to our web page "Reporting a Live/Dead Sea Otter". For additional information on sea otter populations click here for the latest press release from USGS.

Protozoal Encephalitis

An important and apparently new emerging disease is caused by single celled parasites that grow in the brain of sea otters and cause convulsions, severe depression and death. This problem has been diagnosed in some animals originally thought to have died of boat strike or shark bites (they may have been too severely effected to avoid them). Dr. Melissa Chechowitz of the U.C. Davis Wildlife Health Center working with Drs. Pat Conrad and Linda Lowenstine (UCD) have identified two species of parasite, one of which, Toxoplasma, is most often associated with cat feces. They have successfully isolated the parasites for the first time from sea otter brains and are developing a serologic test to allow us to determine the local prevalence and range of this disease.

Thorny Headed Worm

Dr. Murray Dailey (The Marine Mammal Center) and his graduate student Karl Mayer (Moss Landing Marine Lab) are working with us on the thorny headed worm (acanthocephalan). It causes emaciation and peritionitis and kills a significant number of sea otters. Although this parasite has been around for some time, it has only fairly recently become a significant cause of mortality. There is interest in whether there has been a shift from relatively nonpathogenic species of thorny headed worms to more pathogenic species. Changes in sea otter diets to less preferred prey species (sand crabs) may play a role in this.

Contaminants

Under funding from the Oiled Wildlife Care Network prey species of sea otters in Elkhorn Slough and Moss Landing Harbor areas are being analyzed for pesticides, PCB's, heavy metals, and polyaromantc hydrocarbons. This work is being done at the CDFG-Moss Landing Marine Pollution Lab and the Rancho Cordova Water Pollution Lab. Serum from apparently health free-ranging sea otters is being analyzed for contaminants as well. This work is supported by Avila Beach oil spill settlement funds. Serum samples are being analyzed at UC Santa Cruz laboratories where they previously examined nearly a hundred Alaskan sea otter samples.

Post mortem Examinations

Three out of every four sea otters that die and are found fresh are autopsied at the MWVCRC. The USGS National Wildlife Health Laboratory looks at one in four fresh dead. All of the less fresh carcasses are also examined at MWVCRC. Since February 1999 the MWVCRC has had a full time pathologist. Our current contract Pathologist Dr. Melissa Chechowitz examines sea otters, sea birds that die in gill nets, wildlife that die as a result of oil spills, and assists the Marine Mammal Center with the examination of tissues from marine mammals.

Marine Ecosystem Health Research

Dr. Dave Jessup, the MWVCRC's program director has been working on the development of a program to use sensitive marine bird and mammal species to monitor marine ecosystem health. The objective is to combine existing data sets from CDFG and other agencies and organizations in a comprehensive way.