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Toxic kitties (and other otter tales)

Are felines killing otters by elimination, or is this just another environmental ruse?


In order to really understand the often-precarious biological position of the California sea otter, it is necessary to first swim a figurative mile or two in the skin of one of these unique mammals.

Not really a bad assignment, considering you will then be able to relax in the azure blue waters of one of the finest ocean environments on earth, encased in a waterproof pelt of luxuriously thick, wondrously soft fur, munching the finest, freshest, and rarest abalone sushi to be found anywhere, all the while enjoying a warm Pacific sun toasting your tummy to a terrific tropical tan.

It just doesn’t get any better.

Unless, of course, you’re floating in cat feces.

While this might not cause a sense of big concern among the otters, it has been disturbing to some scientists and environmentalists to discover of late that a microorganism found most commonly in the feces of cats–both feral and domestic–has been killing a measurable number of otters.

Researchers from the U.S. Geological Survey National Wildlife Health Center, the University of California-Davis, and the California Department of Fish and Game recently revealed the cat scat clues in a joint scientific report compiled by the agencies.

But is this a big problem, or just an interesting phenomenon with the root of its cause emanating from more than one source?

In a world where the Southern sea otter regally reigns, however, such a situation cannot go unnoticed by the general population.

"The only way we know this toxin can be introduced is through cats," said Mike Harris, a sea otter biologist and environmental scientist for the California Department of Fish and Game. "But we don’t know. There could be another source out there that we haven’t learned about."

"We think the oocysts from cat waste may get transported to the ocean from fields and yards by surface runoff after storms, or due to landscape irrigation," said Dr. Melissa A. Miller, co-author of the study, in a statement. "Sea otters generally live near the shoreline, so they would be directly in the path of these biological pollutants if they reach the ocean."

Some scientists trace the possible source of the cat waste to "flushable" cat litters, a relatively new product in the pet supply industry.

Harris, who divides his time between an office in Morro Bay and the Marine Wildlife Veterinary Care and Research Center in Monterey, said he considers himself to be more of a long-term thinker, and doesn’t see a major crisis, at the moment, in the possibility of cat scat contamination.

"Like other otter issues, this is a situation where only some information reached the public," said Harris, suggesting that media attention to the circumstances may have been overblown.

The story "snowballed in the media from ‘this is what we suspect the problem is’ to ‘this is what the problem is.’ Only as our base of knowledge expands will we get a better handle on this matter."

Fur traders nearly wiped out the sea otter along the Pacific Rim in the 18th and 19th centuries. And last April biologists expressed concern for the species after they noticed a growing number of dead otters washing ashore in California.

Joint state-federal studies recently found high proportions of Toxoplasma gondii infection in dead and sick otters, generally in areas where fresh-water runoff enters the sea. The study showed a high rate of infection: 42 percent of live otters, 62 percent of dead otters. Cats are the only animals known to carry the gondii organism.

For those who view these kinds of things with alarm, the cat feces infection possibility points to a larger, more global problem.

"Otters are very important bio-indicators that give us indications about the whole health of the marine shore environment," said Harris.

This "canary in the mine" concept serves as an early warning for scientists who keep tabs on the ocean’s health.

It is providential, perhaps, that otters have reached their lofty social status as monitors of the earth’s environmental quality.

At one time, the Southern sea otter numbered more than 25,000, scientists believe, although the California species has never been as plentiful as those found north of this range, in British Columbia and along the coast of Washington state. That was before humans discovered the superlative fur that covered the bodies of these marine mammals, and hunters began a wholesale slaughter that lasted for decades.

During the late 1960s, federal biologists noted a rapid decline in the numbers of the sea otter and started the "otter stranding program" to document the number and causes of death among otters.

That puts Harris and his colleagues on the beaches of Central California, recovering the dead carcasses of otters and providing them for necropsies, the animal equivalent of an autopsy.

Otters die of many things, not the least of which are shark attacks and pollutants.

From a large plastic storage chest, Harris removed the tanned pelt of an adult otter, pointing to multiple puncture wounds through the skin.

"Sharks do not eat otters, but they will hit them on the surface of the water. Then they spit them out, just like humans. But with our limited database we just don’t know if these sharks are attacking healthy animals or were drawn to a sick animal that might be convulsing on the surface," Harris said.

So much remains a mystery about the life cycles of otters. But about one thing there is no mystery: California’s sea otter is the darling of conservationists. Its public popularity–attributable, said Harris, to its "cute and cuddly appearance"–has helped it achieve a place of distinction in federal and state law. The heavy weight of sanction awaits those who try to reduce the otter population through unlawful means.

But not everyone likes the sea otter, or the way the species is managed. Wildlife management sometimes creates, rather than solves, problems.

When federal biologists wanted to reintroduce wolves into the wild in Wyoming and other mountain states several decades ago, the response from ranchers was heated. More wolves, enjoying the strictest of game protections, were combing the ranges and decimating sheep and cattle herds, and in some cases creating huge financial crises for ranchers.

There are many people who think the otter is just a seagoing wolf.

Sea otters along the California coast have been increasing their range slowly over the same period of time, and as they move, entire fishery populations are put at risk.

Over a single generation, the abalone–a favorite food of the sea otter and once amazingly abundant–has almost been rendered extinct along this state’s coastline.

The world-famous Pismo clam, a delicacy that once enjoyed immense popularity with clam diggers on the coastal city’s beach, is a fishery that now finds itself in extremely sad shape.

And scientists generally agree that the sea urchin, another creature that finds itself on the otter’s daily plate, is the next fishery slated to feel the hunger of the cute carnivore.

Harris readily acknowledged the impact otters can have on existing fishery resources, because the animal is known to have a voracious appetite, will eat until it can find no more food, and then move on, expanding its range as numbers increase.

"There was a big family tradition in clamming and abalone hunting," said Harris. "That is what people did for recreation. And the otter has had a very clear impact on prey bases."

He shook his head slowly.

"Next, it’s going to be the lobsters in Southern California" as the otter expands ever southward, Harris added.

Those "prey bases" are also part of a larger ecosystem, the health of which impacts entire economies.

Harris, a 1990 graduate of Cal Poly who has been with the otter program throughout his entire professional career, said he was working on the project when the otter "began expanding its range down into the Shell Beach area."

The Pismo clam fishery felt the impact immediately, Harris noted.

The scientist said he thinks the public is not well served by the media when it comes to otter education.

"You have a segment of people who see the otter as just this cute critter that needs to be protected at any cost," he said. "Others see the importance of otters in the marine system and the value of having otters back in their historic range, for the biological diversity they create. Then there are those who just do not like the otter. We have a diverse group that you have to deal with in relation to management."

That’s putting it mildly. For every group of ecologists interested in helping the otter propagate, there is another advocating population control for the preservation of other marine species.

The goal of some conservationists in relation to the future of sea otters is very broad. For example, one prominent California group called The Otter Project sees as its mission a healthy sea otter population; a productive, diverse, and healthy marine ecosystem; and sustainable fisheries along the California coast.

If the occasional purposeful killing of an otter is any indication, others have a future quite different in mind for the sea otter.

Harris worries about a popular misconception that otters are in a dangerously diminishing population cycle.

Take this comment, published on the web site of the American Veterinary Association: "Over the past 10 years, southern sea otters have been dying at an alarming rate, according to experts, who say emerging diseases, shark predation, pollution, and human interference are threatening the future of this ecologically important species."

Just as this kind of information settles into the public psyche, along comes a whole new set of statistics:

A recent count of California sea otters showed a regenerating population of 2,505, a number that has biologists breathing more easily and commercial-fishing operators hyperventilating. That’s about 400 more than a year ago.

But Harris notes that many factors can affect the final numbers in a survey of animals that is constantly on the move.

"Weather conditions, the skill and experience of the people counting, the speed at which the animal is moving along the coast–all these have an impact on the final numbers. So to think that the otter population is healthier and growing is only to speculate. We have to see the numbers over a period of years to reach any kind of conclusion," he said.

But there is some reason for glee for otter fans.

"This is the highest total count and the highest count of adult and young adult sea otters, 2,270, since current standardized methods came into practice in 1983," USGS biologist Brian Hatfield said in a recent statement.

Otter management may be a little bit like cat wrangling, because the critters just won’t do what is expected of them.

The federal government came up with a plan that would keep all of Southern California free of the sea otter in order to protect that fishery.

"That turned out to be a much larger job than anyone imagined. The feds are now in the process of reviewing that plan. It is likely there will be changes. Fishermen are really opposed to the plan," said Harris. "I like fishing, too, so I really see where these people are coming from."

But federal law calls for the rigid protection of California’s marine mammals, including the sea lion, the seal, and the otter, and it is unlikely, said Harris, that the public would allow any changes in the status quo.

So for the time being, here’s a message for Southern California’s delicate lobster fishery: Watch your tails. The otters are coming. Æ

New Times News Editor Daniel Blackburn can be reached at

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