July 2006
Canaries of the Sea
Hidden Plagues Beneath the Waves
By Hallie Gardner
The Marine Mammal Center — an expansive complex of buildings, huts and more than two dozen salt-water tanks — sits on a hilltop north of San Francisco overlooking the Marin County coastline. I’m enjoying this panoramic view while I wait for Dr. Tracey Goldstein to complete a necropsy (the veterinarian’s equivalent of an autopsy) on a sea lion.
Dr. Goldstein, a young woman with hair swept back in a blonde ponytail, emerges to greet me, and we set off on a trek through the mud to meet the Center’s marine inhabitants. I’m introduced to Ohno, a large adult California sea lion, who waddles up to the chain link fence surrounding her enclosure — an open-air pen that contains a small swimming pool with a ramp for easy access. Ohno regards us with imploring eyes, as if hoping for a tasty fish.
Ohno is being treated for domoic acid poisoning, a marine affliction that has been exterminating marine mammals in increasing numbers. During the phenomenon known as “red tide,” when algae grows fast and blooms red, the chemical domoic acid, produced by some species of algae, can accumulate in the oceanic food chain until it reaches poisonous concentrations.
It also crosses the species barrier. The first reported case of humans succumbing to this toxin occurred in Canada in 1987, when three people died after eating contaminated mussels. In 1998, sick and dying sea lions, the first known marine mammal victims, were found washed up on central California beaches. And in the eight years since, domoic acid has killed thousands of sea lions, whales and dolphins along the Pacific Coast.
Although red tide events are increasing in frequency and severity worldwide, scientists have yet to determine precisely why they occur. Evidence suggests red tides are caused by some toxic cocktail of factors including fertilizer runoff, over-fishing and global warming.
Domoic acid poisoning is just one of many killers that have begun to infiltrate our oceans since the 1980s, when researchers first began reporting mass die-offs among marine animals around the world. A 1999 Science survey of marine epidemics between 1931 and 1997 found that nearly 80 percent had occurred after 1980. The researchers warned that, “Epidemics must also be affecting less apparent species, many of which may be disappearing without notice.”
In the last 20 years, more than 50,000 harbour seals (roughly 10 percent of the world’s population) have washed up dead on the coast of Europe, the victims of phocine distemper virus, an affliction associated with organochlorine pollution. Periodic outbreaks of brevetoxins, another poison produced during red tides, have been killing endangered Florida Manatees. Infectious germs and toxins have killed bottle-nosed dolphins along the eastern and southern coasts of the US. And diseases affecting coral reefs have increased exponentially worldwide.
Ocean Epidemics
When it comes to treating victims of ocean epidemics, toxic spills or ship collisions, the nonprofit Marine Mammal Center is a critical first-responder. The Center is dedicated to the rescue and rehabilitation of sick and injured marine mammals and to the study of diseases that impact their health. Marine mammals found stranded on beaches throughout California are brought to the Center by volunteers. To date, more than 10,000 seals, sea lions and dolphins have been treated at the Center’s four facilities in Sausalito, Anchor Bay, Monterey and San Luis Obispo.
Speaking loudly over the din of barking seals, Goldstein explains that Ohno was found writhing with seizures on a beach in San Luis Obispo a month earlier, but her recovery looks promising. Unlike most of domoic acid’s victims, Ohno stands a good chance of being released back to the ocean.
A nearby sea lion pen houses Pisces, who was found suffering domoic acid-induced seizures on a beach in Santa Cruz. “Pisces is still very disoriented,” reports Goldstein. “She can’t coordinate her flippers up the ramp properly; she still doesn’t really have her wits about her and isn’t sure what’s happening.” Pisces was brought to the Center a few days after Ohno and has a less optimistic prognosis.
As we watch, Pisces’ body suddenly starts shaking from head to tail. “This is what we typically see,” Goldstein explains. “When they first come in, they have full-on seizures and, as they are treated, they get tremors from time to time.”
The world’s oceans cover three-fourths of the Earth’s surface and are the Earth’s primary life-support system. So, if the oceans are in trouble, we are, too. The tremors afflicting Ohno and Pisces are flashing danger signs. “Marine animals are providing early clues of our unseen impact on the sea,” says Paul Sandifer, senior scientist for the US National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science. “There is mounting evidence that our activities on land are taking a toll on the health of the oceans, and, in turn, on our own wellbeing.”
Scientists have investigated the fossil record in vain to find historical precedent of a catastrophe comparable to current ocean outbreaks. Their research suggests that marine diseases today are more destructive than any in our geologic history. “Marine diseases have always been with us,” says Richard Barber, a biological engineer with Duke University. The chilling difference is that “they used to be unusual.”
Bumps and Blind
In Hawaii, I meet with Marlu West, president of the Oahu-based Save the Sea Turtles International, a foundation she runs from her home on the Island’s North Shore. West is affectionately known as “the Turtle Lady,” for her relentless work advocating sea turtle protection. Agile and energetic at 60, and an avid body boarder, West appears 20 years younger. From her balcony overlooking Chun’s Reef, a world-famous spot in Kaneohe Bay for surfers and sea turtles, we ponder blue-green waves crashing into bubbles on the beach.
“I grew up in Mexico,” she recounts, “and my father had a sea turtle farm. He used the turtle skin and turtle meat to make all kinds of products. There were so many turtles every place in Mexico. When you went to the beach, you’d have to step on turtles to get to the water. It never crossed my mind that there would be a problem with them.”
Sea turtles have been swimming the world’s oceans for approximately 200 million years. They’ve survived the rise and fall of the dinosaurs. Once abundant, by the 1970s they had been hunted to the brink of extinction. Since all seven species of sea turtles were granted protection under the Endangered Species Act of 1973, these magnificent creatures have been on the path to recovery. Unfortunately, however, a number of Hawaiian green turtles are still afflicted with tumors.
These tumors, known as fibropapilloma, begin as small, localized lesions, but they rapidly grow so large that they can interfere with — or actually prohibit — swimming, feeding, breathing or seeing. Death is the common outcome. Fibropapilloma has affected all seven species of sea turtles to a greater or lesser extent, and up to 92 percent of those in a small Kaneohe Bay reef were afflicted in 1991. It’s not just Hawaii that has this problem. On Florida’s east coast, where the Indian River lagoon has been poisoned by pollution from development and agriculture, more than 72 percent of green turtles were affected in 1998.
George H. Balazs of the Marine Turtle Research Program at the Pacific Islands Fisheries Science Center in Honolulu is quick to point out that, “The disease today is declining in both prevalence and case severity. So far it has had no detectable adverse affect on the population growth and biological recovery of the Hawaiian green turtle.” However, he adds a caveat that, “It may never be completely ‘dead’ but rather persist for the foreseeable future at modest-to-low levels.”
West regularly brings stranded, tumor-riddled sea turtles to the veterinarians at the Marine Fisheries Science Center. While there’s no cure for the disease, the vets can help by removing the growths. “If the turtles are sick, we should be paying attention to why they are sick,” West says passionately. “They are our canary in the sea. Fibropapilloma is a wake-up call for humanity.”
As we watch the sun setting over Chun’s Reef, I ask West if she is optimistic about the sea turtles’ future. “Humans are the ultimate problem for turtles,” she replies. “The world is so interconnected now that we really have no boundaries anymore. If human beings can get it together and stop polluting our oceans, maybe they will make it.”
Hallie Gardner, a Bay Area environmental writer, has an MA in Environmental Studies from USC.
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