Will the King of the Rock Fall? - Pacific Standard
The fathers of ecology lavished attention upon it. The scientist who coined “keystone species” chose it as the prime example. What will happen to the Pacific Coast if its iconic ochre sea star wastes away?

Haystack Rock stands in a sometimes-underwater world set between ocean and beach in Cannon Beach, Oregon. Here, when the tide rolls out twice a day, leftover water sits in pools in the sand and, for a few hours, Haystack’s once-submerged life is revealed. Crabs named after pottery, chitons adorned by algae, mussels, and anemones with pink-tipped tentacles sit in the dripping, rocky nooks. Life in this drenched community of rock and sand is teeming— with the exception of one powerful creature.

“I would find their organs in the tide pools,” says Samantha Ferber, her petite stature swallowed by oversized muck boots and a red raincoat branded with “Haystack Rock Awareness Program.” Standing in the sand surrounding Haystack, Samantha says that it’s her first year as coordinator of the conservation group and already, she’s seen thousands of dead sea stars—popularly known as starfish—and heard of millions more.

You can tell the animal is infected when you spot that first white lesion, she says, pointing to some discoloration on a star’s damp, bumpy, and slightly deflated skin. The colorless cut seems so out of place on this deep burgundy body. As the wound expands, she says, it will tug at the star’s skin, restlessly pulling and tearing until, looking like bits of pinched-off bread dough, one bleached arm after another detaches from the body.

Arms crawl independently away from the animal’s core until disconnected stubs and limbs are found spread over the shallow pools. The dead stars eventually disintegrate into shapeless clumps of white tissue, she says — the formerly five-pronged figures unrecognizable.

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Haystack Rock is among the most photographed landmarks on Oregon’s coast, and a bit of a tourist destination with minor claims to fame like being the beachy backdrop to Steven Spielberg’s The Goonies, as well as a desktop image option shipped with Windows 7 computers. In the conservation community, however, Haystack is currently best known as the site of a mass death.

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Ochre sea stars are often found overlapping one another along the northern Pacific rocky intertidal zone. (Photo: Drew Harvell)

Compared to last year’s sea star population, Ferber says more than 90 percent of stars have disappeared—or, rather, dissolved—from the area.

“Sea star wasting syndrome” is killing stars at and far beyond this popular rock. To date, the wasting has taken millions of stars throughout the northern Pacific coastline, from Alaska to Baja Mexico, and is being called nature’s deadliest marine die-off in remembered human history, says marine disease expert Drew Harvell. Scientists recently discovered the most likely culprit, an infection caused by virus. Though similar kinds live harmlessly in other creatures, this “sea star associated densovirus” is the first virus ever found in sea stars, feverishly infecting some 20 species.

Among the infected, five stars have uncomfortably high death tolls—the giant pink, the sunflower, the mottled, the morning sun, and one other that is uniquely connected to its community and thus, lost with particular regret.

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The ochre star, Pisaster ochraceus, comes in a wide spectrum of skin colors, from burgundy or bright purple to brown to orange. (Some scientists think the stars’ diet accounts for the diverse palette.)

In the late 1930s, the ochre was defined as “the common sea star,” the most obvious member of the surf-swept rocky coast, in the book Between Pacific Tides. Penned by philosophers-cum-marine biologists Ed Ricketts and Jack Calvin, this Pacific coastal guidebook is more or less a bible for today’s West Coast marine biologists. “That’s like, the book,” says Melissa Miner, part of the Multi-Agency Rocky Intertidal Network, which surveys some of the same coastline that Ricketts and Calvin did in the '30s, likely counting ancestors of the same anemones, barnacles, mussels, and stars that the duo once noted.

Ricketts and Calvin spoke of marine life as connected in a way that no one had before, outlining a system of balanced being rather than referring to organisms as individuals. Their holistic perspective of community living transformed ecology, the study of how organisms influence one another. No longer just a naturalist’s heady hobby, ecology, thanks to these ecological cowboys, became a serious scientific endeavor.

Between Pacific Tides imparted a particularly fond focus on the ochre star’s home. Ricketts deemed the intertidal zone, the sometimes-submerged habitat between beach and ocean, “possibly the most prolific life zone in the world.” Temperature, food, and safety here are in constant flux, he wrote. With the tide high, organisms live underwater in stable and comfortable conditions. But when it rolls out and the water is low, animals must survive in open air, either freezing or roasting with the extremes of changing seasons.

Of all members in this hardy intertidal community, Ricketts wrote, the ochre star is perhaps the most robust: “Anything that can damage this thoroughly tough animal, short of the ‘acts of God’ referred to in insurance policies, deserves respectful mention.” Equipped with hundreds of tiny, suction-cup tube feet, ochres have adapted to never be detached from their rocky roost. With hard bone encased in ridged skin and arms that regenerate when bitten off, they have few true predators.

Though no bigger than a thick pancake or a Frisbee, “The ochre is like the king,” says Harvell, the marine disease expert. Like most star species, it has a carnivorous appetite and eats comfortably atop the local food chain. The ochre’s mere scent in water can send prey fleeing, usually with as much speed and vigor as a shelled creature can muster, Ricketts wrote. By the 1960s, ecologist Robert T. Paine conducted two studies to test the real import of this star’s predatory presence; he wanted to see what would happen to the intertidal community if the ochres all went missing. Armed with a crow bar and the methodology of science, he detached the ochre stars from a stretch of rocky seashore just off the western tip of Washington, and then tossed them into the water.

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Haystack is a popular, 235-foot rock standing in the intertidal zone along Cannon Beach, Oregon. (Photo: cjuneau/Wikimedia Commons)

With ochres missing, the number of other species living along the seashore dramatically cut in half by the following year. Community members like algae, limpets, and, later, barnacles, all left due to a lack of food and space, caused almost entirely by a massive incursion of the ochre’s most preferred prey—the mussel. “The removal of [the ochre sea star] has resulted in a pronounced decrease in diversity,” Paine wrote in the 1966 The American Naturalist paper.

Three years later, Paine more clearly defined this extreme community dynamic observed in Washington. In a second paper on the ochre’s essential role in the intertidal zone, he employed a term that (though excessively used today) had never been heard before. Paine likened the ochre’s position in its ecosystem to that of a keystone, the most integral building block in an arched structure—the single piece without which the entire system would fall to pieces. The ochre star was described as the world’s very first keystone species.

Not only the foundation of intertidal life, the ochre is also culturally crucial to communities of the human sort. With dull white spines that resemble fishing nets spread over their stout bodies, ochres are an omnipresent symbol of the Pacific Northwest coastline. “When people come here, they expect to see these stars,” Ferber says. They are about as charismatic as a faceless, hairless, intertidal creature can be. “I have their picture on my desktop on my computer screen,” a fellow red-cloaked Haystack Rock volunteer says. And when local families come exploring tide pools on the weekend, the first thing kids get animated about is “a starfish!” Ochres are so synonymous with this coastline that a quick Google image search for “Oregon coast tide pools” reveals that 32 of the first 50 results feature an ochre, often several side-by-side in the same shot.

In fact, it is this tendency to live close together, frequently overlapping, that may explain why the current wasting syndrome spread so rapidly. “Where you find one sea star, you tend to find another, and that’s probably good for contact transmission [of the disease],” says ecologist Kevin Lafferty from the Marine Science Institute at the University of California-Santa Barbara.

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With the disease causing a 90 percent star decline at a site like Haystack Rock, marine biologists worry that Paine’s ochre removal experiments have been unintentionally recreated. Oddly, Miner says, “that’s kind of the silver lining.” The sudden loss of sea stars is allowing scientists to verify the effect of missing stars on a much greater scale.

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A top predator in the intertidal community, the ochre's most preferred prey is the mussel. (Photo: Dave Cowles/Walla Walla University)

Normally, by summer’s end, areas with a lot of ochres are empty of their prey, like mussels. But “that wasn’t true this year,” says Bruce Menge, a biologist who has studied Oregon’s marine communities for over 40 years: The number of mussels and other prey actually increased in the intertidal zones by the close of the season. Menge, who studied under Paine, says this is the first sign foreshadowing the effects his adviser observed decades earlier—at an unsettling magnitude spanning the Pacific Coast, he adds.

From his perspective as a scientist, Menge recognizes that the loss of the ochre is a learning opportunity. But “from a human standpoint,” he says, “it’s a disaster.” If ochres don’t recover by next summer, Menge says we’re likely to see the beginning stages of complete mussel domination in the intertidal community. And the odds of preventing this black-shelled bivalve’s takeover, and of ochres making a comeback, still remain hazy. At the moment, the disease’s spread seems to be slowing. There are fewer stars with signs of wasting, and when they are infected, symptoms are less severe— not as many detached arms. But, “there are clearly many fewer stars overall,” says Miner, so fewer sightings are expected. “We’ll need to wait to see if they survive.”

If this star does not endure, if the ochre falls, the Pacific Coast intertidal communities that our original ecologists knew (“Everywhere there is color, life, movement”) could become a mere memory of environmental history. Just as the ochre star is no king without its community, without the ochre this medley of intertidal life could disappear. In diversity’s absence, just one dark-shelled member would reign—a new, and less accommodating, intertidal king.

Lead photo by Drew Harvell.

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