"Change is inevitable... Survival is not"

photos courtesy Alan Studley

"If (otters) pick it up, we have the potential of picking it up as well, because we share the neighborhood," Murray said.

Otters are a convenient way of getting at the bigger picture because they are an excellent sentinel species. To help stay warm in cold seas they eat 25 percent of their body weight a day in clams, crabs, snails, starfish, abalone and 40 other marine animals. That makes them a "bio-accumulator" of their environment, Murray said.So what shows up in otters is likely common to that environment. Like the canary in the coal mine that will die from poison gas before humans detect it, a sick otter may indicate a sick ecosystem.And prominent scientists though they are, the study's researchers are aware of the sentimental attachment many people have for the otter, the Central Coast's unofficial mascot."All of us have a feeling that otters are aesthetically pleasing and important from a conservation perspective for Monterey Bay and the Pacific Ocean, (but) we also feel they are a very effective sentinel species that allows us to gauge the health of the near-shore marine ecosystem," Jessup said. "They're doing us a tremendous service."

Here are pathogens found for the first time in otters and that are found in the feces of infected humans, with information on them from the U.S. Food and Drug Administration and the Centers for Disease Control.

Sewage May Be Harming Sea Otters

Researchers are starting to compile evidence that land runoff or sewage spills may be harming sea otters, possibly even reducing their numbers. And, the researchers warn, otters are a "sentinel species" that can indicate wider harm done to their environment.A recently completed study, funded by a Pacific Grove sewage-spill fine, found several types of bacteria and parasites in otters that are similar or identical to those that cause gastrointestinal disease in humans. One of the study's authors says it's "highly unlikely" that the bacteria and parasites found in the otters originated in the sea, although researchers say they haven't yet found a "smoking gun" linking the presence of those pathogens in otters to sewage spills or coastal runoff.

Human gastrointestinal diseases found in species

The study, conducted in 2000-2001 by researchers with the Monterey Bay Aquarium, the state Fish and Game Department's Marine Wildlife Veterinary Care and Research Center in Santa Cruz and the University of California at Davis' School of Veterinary Medicine, analyzed 40 samples of otter feces, mostly from Monterey Bay, to seek direct evidence of pathogens also found in humans and domestic animals from cats to cows. It found many, several detected for the first time in otters.Over the past several years, examinations by the research center of otter corpses found along the Central Coast had implicated infectious diseases in more than 40 percent of those deaths, the study summary said. That's "a very high percentage for a wild animal," said David Jessup, Fish and Game senior wildlife veterinarian and supervisor of the research center.Jessup said "diseases appear to be the big cause" for sea otter population declines in recent years. According to census numbers compiled by Friends of the Sea Otter, a Monterey-based advocacy and education group, California sea otters have dropped from mid-1990s highs of close to 2,400 to about 2,000. The California sea otter is found in coastal waters from Half Moon Bay to near Santa Barbara.Preliminary data had suggested that some of the deaths from infectious diseases were caused by bacteria and parasites found in humans and domestic animals. The recently completed study was undertaken as a first step in seeking a definitive link.Researchers involved in the study are careful to say that further studies are needed to establish whether the pathogens found in otters originated from human or domestic-animal waste, spilling into the sea from sewage or runoff from storm drains and agricultural land. But the study demonstrates the need for further and more elaborate research, they say.

"We simply were looking at whether pathogens associated with human gastrointestinal illness are found in sea otters," Jessup said "They are."

Whether there's a definitive link is a question "we want an answer to," said Monterey Bay Aquarium veterinarian Michael Murray, another of the study's five collaborators/authors. Researchers are now seeking funding for studies involving more advanced techniques, such as DNA comparisons, to pinpoint the source of pathogens found in the otters."Circumstantially there seems to be a relationship" linking the pathogens to human sources, Murray said. "We need more of a smoking gun."The city of Pacific Grove contributed $35,000 for the study just completed, which covered about 90 percent of its cost, Jessup said. That funding came from a $70,000 fine the city was assessed by the Monterey Regional Water Pollution Control Agency for a spill two years ago that dumped 70,000 gallons of sewage into Monterey Bay. In paying the fine, Pacific Grove Public Works Director Stephen Leiker said the city had the option of directing it to state Supplemental Environmental Program projects, instead of having it go into a larger statewide pool."I would rather have the money the city contributed to go to something that could be productive at a local level, especially as it impacts the (Monterey Bay) sanctuary and its health," Leiker said.The full implications of the study go beyond sea otters, affecting the near-shore marine environment as a whole - which means that humans using the sea for recreation and seafood may find that what they've been putting into the sea could come back to harm them.

Cryptosporidium, a single-celled protazoal parasite found in two otter feces samples. It is also common in the intestines of people and herd animals, domestic and wild, and causes a disease called cryptosporidiosis that 80 percent of North Americans have had at one time or another, characterized by diarrhea, abdominal cramps, fever and dehydration. It generally lasts two to four days in people with healthy immune systems but can be long-lasting and life-threatening for AIDS patients.- Giardia lamblia, another protazoal parasite, found in one otter feces sample. Found in humans, dogs and cats, mostly commonly from drinking contaminated water. The intestinal illness usually lasts one to two weeks for those with healthy immune systems. - Salmonella, a bacteria found in a dead otter in Santa Barbara County - the otter had suffered from "explosive diarrhea" before death, according to the study. Humans usually get salmonellosis from spoiled or undercooked foods, especially eggs, and symptoms can be severe. - Plesiomonas shigelloides, a bacteria humans get from water-borne sources and that also occurs in many animals. Causes gastroenteritis. Found in seven of the 40 otter feces samples.- Clostridium perfringens, an anaerobic bacteria found in eight of the otter feces samples. People get it from food poisoning, and it causes distress that generally lasts 24 hours.- Camplyobacter, the most common bacterial cause of diarrheal illness in the United States. The illness typically lasts a week for those with healthy immune systems. Found in one otter feces sample.

If trouble is ahead for the sea otter, it won't be the first time.

Heavily hunted for their luxuriant fur in the 1800s, sea otters were thought to be gone forever from the California coast by the early 20th century until a group of about 300 was unexpectedly found 13 miles south of Carmel in 1938.Today's population is descended from that group, and slowly grew to the peak of about 2,400 in the mid-1990s. However, a "low genetic variability" may make them more susceptible to diseases and environmental changes and may contribute to their slow growth since the 1930s, said Matt Rutishauser, science director for Friends of the Sea Otter.Before the hunters arrived, about a million sea otters lived along the coast from Baja California up to Alaska and over to Russia and Japan. The survivors have formed three subspecies isolated from each other - the southern, or California, the Alaskan and the Russian.The California sea otter was placed on the Endangered Species list in 1977, classified as "threatened." In addition to its role as sentinel, otters are considered a "keystone" species that plays a vital role in ecosystem balance by eating sea urchins and other animals that graze on kelp. By helping enhance kelp forests, otters indirectly foster growth of fish stocks that associate with kelp.The study just completed "really illustrates the link between the land and the near-shore ocean environment," Rutishauser said. "They found human pathogens in sea otters, and they came from a terrestrial source of some kind.

 

By DENNIS MORAN
dmoran@montereyherald.com
Dennis Moran can be reached at:
831-646-4348.