Photograph by John Burgess/The Press Democrat
SOLUTIONS | 09.19.17
Fighting for a Foothold
White abalone are both critically endangered and crucial to their coastal ecosystems, so scientists have launched a Hail Mary effort to save them.
Today is Spawning Day—the one time each year when white abalone can be coaxed to release their sperm and eggs, giving researchers the chance to rear the next generation. Each of the 14 brood stock in their care, including the only wild-born white abalone female in captivity, sits in its own bucket, bathing in a hydrogen peroxide solution that, after a few hours, should stimulate the mollusk to spawn. “There’s a lot on the line,” Aquilino explains. With white abalone (Haliotis sorenseni) failing to reproduce in the wild, this program is essential to the species’ survival. But she doesn’t have high hopes for the new wild female, which released eggs out of stress when divers collected her in Southern California a few weeks earlier. “My guess is she’s done.”
After more than a decade of trial-and-error, white abalone are finally hitting their stride in captivity. By day’s end, the wild female will have spawned some 700,000 viable eggs—introducing new genes into the captive population for the first time in 14 years. In total, the team estimated they had created 8 million embryos—20,000 of which they expect to make it to the adult stage. That’s in addition to the tens of thousands of juveniles researchers have already reared in their nursery.
As scientists prepare to release the first captive-bred individuals into the wild in the next year or so, much remains unknown about the ecological role of the marine invertebrate and the rising threats to their long-term recovery: a mysterious disease brought on by warm waters, the predators that exploit naive captive-raised abalone, and the yet-to-be-determined impacts of climate change. Indeed, the coast is hardly clear for abalone in California.
white abalone typically live a hundred feet or more below the surface, so researchers often use remotely-operated submersible vehicles to study them. As a result, research on the basics of abalone biology and ecology has been slow, and scientists were largely unaware of the rapid decline of abalone populations until it was almost too late.
“Abalone’s ultimate downfall is that they’re delicious,” says Jenny Hofmeister, a marine scientist at the Scripps Institution of Oceanography. White abalone, highly prized by markets in Asia and restaurants in stateside Chinatowns, are said to be tastier than the red, black, pink, or green abalone species. In the 1970s, California opened up a commercial fishery for white abalone, and divers gathered the animals by the hundreds of thousands. As white abalone became rarer in the wild, the price per pound jumped from $2.50 in 1981 to $7 in 1993—roughly double the value of other abalone species. Before long, the abalone that remained on the seafloor were too few and far between to reproduce.
Fearing extinction, the California Department of Fish and Game banned commercial fishing of white abalone in 1996 and of all abalone species in 1997. Today, the only fishery that remains is for recreational fishing of red abalone in northern California, where their densities are still sustainable. But that hasn’t stopped white abalone from showing up in fishermen’s hauls. Today, a single white abalone can sell for hundreds of dollars—a temptation some divers are unable to resist. Aquilino says she’s heard people describe it as “finding a $100 bill on the ocean floor.”
“Something knocked them out,” says Buzz Owen, 82, a retired commercial fisherman and avid abalone researcher who first described hybridization among various species. “But there were multiple things at work.”
On top of illegal harvests, a disease called Withering Foot Syndrome first showed up near the Channel Islands off the southern California Coast in 1986, and by the 1990s it had spread to waters near the mainland. Once infected, abalone stop eating. The abalone is then forced to consume its own body mass, causing the foot muscle to wither and lose its life-giving grip on the rocky seafloor. The deadly disease affects every abalone species in California, but white abalone are particularly hard hit.
Even more troubling, the emergence of Withering Foot Syndrome is temperature-dependent. A white abalone in a lab, under optimal conditions, can be infected with the pathogen and not experience any symptoms. But as soon as the water temperature warms to between 18 and 20 degrees Celsius (64 and 68 degrees Fahrenheit), the disease kicks in, killing the mollusk within months.
To make matters worse, rising ocean temperatures are also wreaking havoc on the animals’ habitat and food sources. Kelp forests need temperatures between 5 and 20 degrees Celsius (41 and 68 degrees Fahrenheit) to thrive. When water temperatures increase, the amount of dissolved inorganic nitrogen drops, and kelp abundance begins to fall as well.
A Brief History of White Abalone
inside the California Department of Fish and Wildlife’s Shellfish Health Lab, the invertebrate pathologist is peering through a microscope, examining dyed tissue samples taken from captive white abalone. He’s hoping that by documenting the process of necrosis—what an abalone’s tissues do after the animal dies—he’ll be able to sort out the difference between changes caused by pathogenic disease and those that happen naturally after death. “It’s difficult for us to figure out when an abalone is really dead—often once [researchers] realize, it’s been dead for a while,” he says. This makes it hard to know if an infection took hold before the animal died (perhaps causing death) or after.
To keep Withering Foot Syndrome at bay in the nursery, Moore gives the animals a bath in an antibiotic called oxytetracycline and treats them with UV radiation as soon as they arrive. Researchers can douse the animals once more before stocking them in the wild, to protect them from the disease for a few more months, but without continual treatment the abalone are likely to become infected.
The challenge that remains is figuring out how and where to return the captive-bred abalone to the wild once researchers receive federal approval to release them—possibly within the next year. Even if scientists manage to protect abalone from poachers and disease, predators threaten to undo all the gains achieved so far.
rolls in the choppy waters off San Diego as pelicans dive like sharpshooters around the boat, snapping up fish and gulping them down quivering gullets that reverberate with each flop. Sea lions and porpoises swim by, taking advantage of the ocean’s bounty. On the horizon, a California Department of Fish and Wildlife enforcement officer patrols the protected waters, on the lookout for possible poachers. But today, most of the action is happening far beneath the waves.
After 45 minutes, a stream of fizzing bubbles rises to the water’s surface, signaling the return of divers Jenny Hofmeister and Arturo Ramirez. The two waterlogged black shapes emerge from a cloud of tuna crabs and weedy kelp and haul themselves from the cool water along with mesh bags filled with a collection of sea creatures. After a quick swig of ginger tea to warm up, Hofmeister begins sifting through her scavenged treasures: an empty cowrie shell; five Kellet’s whelks; a starfish; and a half-dozen red abalone shells, their occupants long-since eaten.
Octopuses are abalone’s most voracious predators in deep water, but crabs, lobsters, and fish will target them, too. Captive-bred abalone released into the wild, researchers theorize, are stressed in their new environment and haven’t developed fast-acting fear responses yet. The abalone’s first lines of defense are passive: camouflage and a hard shell. If pursued by a slow-moving predator, like a starfish or predatory snail, abalone can retreat, if only at a literal snail’s pace. When faster-moving threats approach, abalone can engage their mollusk death grip, clamping down on a rock and holding on for dear life. But studies show that farm-raised abalone don’t clamp down fast enough. And even if they do, some predators, like octopuses, are able to bore through their shells.
So far, about 700 of the 7,200 outplanted red abalone from the trial have been accounted for across nine sites in coastal Los Angeles and San Diego, 400 of them dead and 300 alive. The site Hofmeister is monitoring today seems to be showing better survival rates than other locations as well as fewer predators. As she packages each abalone shell in a small plastic bag, another dive team swings by in their boat and passes over a white plastic bucket containing a California two-spot octopus (Octopus bimaculoides) collected at one of their survey plots.
Hofmeister pulls out her measuring stick and takes a read of the size of the octopus’s mantle. Then she checks for any physical damage; tentacle R2 is missing its tip, but it will regrow. Last, she sexes the octopus and estimates her to be six months old. By year’s end, she’ll double in size. “Don’t ink, don’t ink, don’t ink,” Hofmeister mutters as she returns the animal back to the bucket of water.
Photograph by Gloria Dickie
our boat is harbor-bound, speeding over dark blue waters. The clouds that hung low throughout the morning have dissipated, and the mansions of San Diego loom large above the shoreline. Mitt Romney has a $12 million beachfront vacation home here, not far from John McCain’s $1 million luxury condo.
In this part of southern California, where white abalone have all but disappeared, sea urchin populations have exploded over the past 20 years, forming so-called “urchin barrens.” With no abalone around to compete for habitat and vital resources, urchins move out of subtidal cracks and crevices to mow down kelp and the ecosystems the plants support. In California, it’s these kelp forests that protect coastlines from wave action. “They absorb a lot of the ocean’s energy,” explains Hofmeister. As sea levels rise, waves will likely be able to travel farther inland, even during calm conditions, eroding away land. Storm surges bring larger waves, and with them, the potential to cause catastrophic damage. “Without kelp forests, Romney’s house is going to be gone,” she says.
“The kelp forest is an ecosystem that supports a lot of different species,” explains Hofmeister. Remove one of those species, and the whole ecosystem can crumble. When sea otters disappeared in the Aleutian Archipelago in southeast Alaska, for example, urchins exploded and ate all the kelp until the forest disappeared, and with it many of the species it supported, such as seals, sharks, and sea lions. But when sea otters were extirpated in southern California, where other species that preyed on the urchins still existed, the forests remained resilient. “The more biodiverse an ecosystem is, the more resilient it is to change,” Hofmeister says. “Diversity saved the kelp forests then, and diversity is what is going save the kelp forests now.”
Interactive by James Davidson
Header: A white abalone at the Bodega Marine Lab. Photograph by John Burgess/The Press Democrat
The Bodega Marine Lab on Horseshoe Cove.
The Shellfish Health Lab.
A dyed sample of diseased abalone tissue.
Homes overlooking the waters of San Diego. Photograph by Gloria Dickie.
Footer: The rocky coast of Northern California.
ABOUT THE Author
Gloria Dickie is a freelance science and environmental journalist based in Boulder, Colorado. Her work has appeared in National Geographic News, High Country News, Hakai Magazine, Quartz, Outside, Discover, and many other publications. Follow her on Twitter @gloriadickie and read more of her work at www.gloriadickie.com.
ABOUT THE Photographer
Kathryn Whitney is the Photo Editor and Photographer for the California Academy of Sciences andbioGraphic
, where she is able to combine her passions for science and photography every day. She is always ready for adventure, whether it’s outlasting a hailstorm while on assignment or galloping semi-wild horses across the Mongolian Steppe.
Gloria Dickie Kathryn Whitney
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