WASHINGTON, D.C. — Researchers have been scrambling for more than a year to make sense of a strange disease that’s causing West Coast starfish to die by the millions.
Now it looks like help could be coming from Congress.
U.S. Rep. Denny Heck from Olympia introduced a bill Thursday that would dedicate federal funds for researching the epidemic, which has now spread along North America’s Pacific coast from Alaska to Mexico and in some places on the East Coast as well.
The disease has hit more than 20 species of West Coast starfish. Scientists are calling it the largest marine disease outbreak ever recorded.
Drew Harvell, a marine epidemiologist at Cornell University, has been studying the outbreaks in Puget Sound and is leading nationwide efforts to understand the epidemic. She says this legislation is critical because tracking marine disease outbreaks is so challenging.
“Disease outbreaks — they’re like lightning strikes. They occur unpredictably and rapidly,” Harvell says. “To identify their causative microorganisms or stop them from spreading requires significant scientific investigations on really short notice.”
ORCAS ISLAND, Wash. — Drew Harvell peers into the nooks and crannies along the rocky shoreline of Eastsound on Orcas Island. Purple and orange starfish clutch the rocks, as if hanging on for dear life.
“It’s a lot worse than it was last week,” says Harvell, a marine epidemiologist at Cornell University. She’s been leading nationwide efforts to understand what is causing starfish to die by the millions up and down North America’s Pacific shores and on the east coast as well. It’s been called sea star wasting syndrome because of how quickly the stars become sick and deteriorate.
“It’s the largest mortality event for marine diseases we’ve seen,” Harvell said. “It affects over twenty species on our coast and it’s been causing catastrophic mortality.”
Scientists have been working for months to find out what’s causing the massive die-off and now Harvell and others have evidence that an infectious disease caused by a bacteria or virus, may be at the root of the problem. The disease, they say, could be compounded by warming waters, which put the sea stars under stress, making them more vulnerable to the pathogen.
Harvell has studied marine diseases for 20 years. She had thought that the syndrome might spare Washington’s San Juan Islands. Until recently, pockets of cold water and swift currents seem to have protected the local sea star population from the epidemic.
But with the arrival of summer, the waters around the San Juan archipelago have warmed. From what Harvell and her team see as they survey beaches, there’s not much time for these starfish — or sea stars, as scientists prefer to call them since they’re not fish.
Harvell crouches in the sand and points at a withering orange pisaster ochraceus, or ochre star, one of the most common sea stars found in the intertidal zones of the West Coast. One arm is curled over on itself, another hangs by a thread of gnarled flesh.
“The whole arm is flat. It looks dried out, wasted, thin, deflated. Sea stars are not supposed to look like that,” Harvell says, her brow furrowed. “My expectation is that within the next month all of the stars will die.”
The team checked this rocky patch last week and found 10 percent of the stars showed signs of the wasting syndrome. Today they estimate that number has increased to more than 40 percent. They’ve been monitoring sites around the San Juan Islands through this past winter and expect the percentage of infected stars to continue rising as the waters warm this season.
“Over this winter I surveyed here, and looked at every animal and there was no disease at all,” said Morgan Eisenlord, a PhD student in Harvell’s lab at Cornell. “When we came back in the spring we found sick animals so it obviously spread as it started to get warmer.”
A Warm-Water Connection?
Some scientists see a connection between rising water temperatures and the wasting syndrome. The waters around the San Juan Islands tend to be colder than the Washington outer coastline where dying starfish were first reported last summer. Since the arrival of warmer weather this season, the syndrome has spread rapidly to areas like the San Juan Islands that were previously untouched by the syndrome. Recent reports have also surfaced of die-offs along Oregon’s coastline.
Farther south in California where water temperatures are even warmer, starfish have been nearly wiped out, according to Carol Blanchette, a research biologist at University of California Santa Barbara. Blanchette has tracked the spread in Southern California closely, monitoring 30 sites. She says the hypothesis that rising water temperatures could be triggering the epidemic makes sense, based on what she’s seen.
Drew Harvell, Cornell University
“The period of time in which the disease progressed rapidly has been a period in which waters have been warmer than usual winter conditions,” Blanchette said.
While scientists are reluctant to assign blame to climate change, Harvell explained that as oceans warm, outbreaks like this are more likely to occur.
“A warmer world would be a sicker world,” Harvell said. “Under warming conditions a lot of microorganisms do better. They grow faster. They replicate faster. Many of our hosts can actually be stressed by warm conditions. And so it kind of creates a perfect storm of sickness.”
Looking Back, Looking Ahead
Sea star die-offs have occurred in the past, but never to this extent. In Southern California, Blanchette says the die-offs have occurred during warmer El Niño years – 1982-1983 and 1997-1998 most recently –- but the sea star population eventually recovered. This most recent outbreak was first spotted in June 2013 on the Washington coast at a place called Starfish Point.
Scientists believe the pathogen spread through the water, as well as via physical contact (starfish often clump together). Another hypothesis is that the pathogen could also be concentrating in the mussels and clams that starfish like to eat.
Scientists are testing whether shellfish, a top food
source for starfish, may transfer the pathogen.
Credit: Laura James
At the University of California Santa Barbara Aquarium, captive sea stars started showing signs of the syndrome at the same time as their wild counterparts who live on the rocks several hundred feet from the tanks. The captive sea stars are kept in tanks of filtered seawater. In one tank they were fed mussels harvested from the rocks outside. In another tank the sea stars were fed frozen squid.
The animals that ate frozen squid stayed healthy, while the sea stars that ate the wild-harvested mussels contracted the syndrome. Blanchette cautions that these observations are purely anecdotal and the sample size is very small, but she believes this hypothesis merits further study.
With projections for a warm El Niño year ahead, Harvell worries that things will only get worse for sea stars on the west coast.
Scientists at Cornell are narrowing the list of pathogen suspects using DNA sequencing from samples of sick stars and hope to publish their findings in an upcoming edition of the journal Science. Once the exact pathogen is identified and more is known about how the disease is spread, scientists will be better able to understand whether west coast starfish will be able to recovery.
Seeking Boots On The Beach
In the meantime, there is a role for citizen science in tracking the epidemic. UC Santa Barbara and the University of Washington and Cornell University have set up websites where beach goers can share information about the location and abundance of infected sea stars. Then scientists can study how water temperatures, currents and other factors may correlate with the spread of the die-off.
“One of the reasons we’re a little obsessed with trying to learn everything we can about both the causative agent in terms of the microbe and the environmental conditions is to think about what we can do better next time,” Harvell said.
What Happens When They’re Gone?
Sea stars are an apex predator in the intertidal zone. They voraciously consume mussels and other shellfish, and they are referred to as a “keystone species,” meaning that, like in any stone building, if you remove the keystone, things start to crumble.
“It has an extraordinarily significant effect on the biodiversity of the entire community,” Blanchette said. “Losing a predator like that is bound to have some pretty serious ecological consequences and we really don’t know exactly how the system is going to look but we’re quite certain that it’s going to have an impact.”
Scientists inspect young starfish for signs of wasting disease. Credit: Katie Campbell
Looking out at the rising tide on Eastsound, Harvell said, “This area has some of the highest biodiversity of sea stars in the world. We’re not just losing one keystone species, we’re losing a whole guild of stars.”
And the stars here are what’s called an endemic species, meaning they only live on this shoreline and nowhere else on the planet, she explained. If sea stars are wiped out along these shores, there’s a potential for not just local, but global extinction.
She picks up a tiny young ochre star and looks carefully at its malformed arms for symptoms of the disease. If these juvenile stars can find a way to resist the pathogen, local extinction could be avoided, she explains.
“If we lose all of the adult ochre stars and all of the young recruits in the San Juans, then I don’t think we’ll see ochre stars here for quite a few years,” Harvell said.
Story by Ashley Ahearn and Katie Campbell. Video by Campbell. Audio by Ahearn.
MUKILTEO — It’s an iconic summertime image in the Northwest: children playing on the shoreline at low tide, shoveling sand into plastic pails while purple and orange sea stars cling to exposed rocks nearby.
On some beaches this summer, that scene likely will be missing the sea stars.
A mysterious condition is killing sea stars — commonly known as starfish — by the thousands all along the Pacific Coast of North America, from Alaska to Baja California.
Sea stars, she said, “are emblematic; people have them on their T-shirts, for heaven’s sake.”
Local populations in the inland waters of Western Washington — including in Mukilteo and Edmonds — have been nearly wiped out just in the past few months, researchers and divers say.
The stars are turning to jelly and disintegrating. A group of researchers is working to find out why.
“It’s extremely difficult to pinpoint the exact cause,” said Ben Miner, an associate professor of biology at Western Washington University in Bellingham.
He recently collected samples of sick and dead sea stars in Mukilteo and Edmonds.
The prevailing theory so far, Harvell said, is that the deaths are being caused by a pathogen, bacteria or a virus, as opposed to a broader environmental condition such as ocean acidification.
Other types of organisms are not experiencing similar death rates, she said. The scourge has been more pronounced in inland waters than on the outer coast.
Populations in Oregon, compared to those in Washington and California, have mostly been spared.
Some inland waters have been hit hard by the die-off, while other areas, such as the harbors at Langley and Coupeville on Whidbey Island, still have healthy populations, Miner said.
Sea stars that live in ultraviolet-light-filtered water in aquariums are mostly healthy, while those that live in unfiltered water are more often showing signs of disease, Miner said.
While the evidence so far points to a pathogen, “that certainly doesn’t preclude the possibility that there are other things in the water that are weakening their immune systems and allowing them to get sick,” Miner said. “It has the potential to be a combination.”
If it is bacteria or a virus, it’s uncertain whether humans are contributing to the problem, Harvell said.
“Once we know what it is, we’ll have a much better idea of what the answer to that is,” she said.
Another theory is that the condition is caused by radiation that has drifted across the ocean from the nuclear power plant in Fukushima, Japan, which suffered a meltdown after the March 2011 earthquake and tsunami.
If that were true, many more creatures would be affected, researchers said.
“It’s unlikely to be the direct cause,” Miner said.
There are several hundred species of sea stars worldwide and about 25 in the Pacific Northwest, he said.
“About half of those species appear susceptible,” Miner said.
Large “sunflower” stars, which have up to 20 arms and can be more than 3 feet across, have taken the brunt of the plague along with the ochre stars, Harvell said.
Kimber Chard, of Edmonds, a scuba diver who frequents the waters of Edmonds and Mukilteo, said he began noticing dying sea stars about nine months ago.
“The sunflower stars used to be everywhere,” Chard said. He used to see up to 30 of them per dive. Now it’s down to two or three.
“There used to be so many of them, and they’re just so few.”
Sea stars are echinoderms, in the same phylum as sea urchins, sand dollars and sea cucumbers. Sea stars are voracious eaters, sucking down clams, mussels, barnacles, snails, other echinoderms and even each other, researchers said. As a result, their losses could send big shock waves through the food chain.
Scientists at universities along the West Coast and at Cornell in Ithaca, N.Y., have teamed with aquariums and divers to work on the problem.
Miner is placing healthy sea stars in tanks with sickly ones to test the contagiousness of the condition. Samples of sick stars are being tested at a marine lab on Marrowstone Island near Port Townsend. Some are frozen, preserved and sent to Cornell researcher Ian Hewson.
“He has the capability to test for bacteria and viruses and he’s worked incredibly hard all fall,” Harvell said.
Miner said he hopes to have some study results to report within a couple of months.
“We’re just watching which way it goes and how fast it goes,” he said.
Casualties of a mysterious disease known as seastar wasting syndrome, they are dying in Alaska, deteriorating in San Diego and disappearing from long stretches in between.
Death from the disease is quick and icky. It begins with a small lesion on a starfish’s body that rapidly develops into an infection the animal cannot fight.
Over the course of the disease the starfish’s legs might drop off, or even separate from the body and start to crawl away, as you can see in the PBS news story below.
Pete Raimondi, a professor at UC Santa Cruz who has been tracking the seastar crisis, said a starfish’s leg moving away from its central disk is akin to a lizard’s tail continuing to wriggle even after it has snapped off the lizard’s body.
“Starfish don’t have a central nervous system, so it’s not like if you chopped off your arm,” he said. “The arms can still be mobile and operate on their own for a period of time – longer than you think.”
The seastar wasting epidemic was first observed last summer. Some wondered whether radiation that leaked into the Pacific Ocean from the Fukushima nuclear plant in Japan might be the cause.
“I think it is almost entirely impossible to be related to Fukushima,” Raimondi told the Los Angeles Times. “We haven’t ruled it out, but there are so many more likely things going on. And there is no evidence that radiation has gotten to California.”
A more likely culprit is a pathogen. Either a virus, parasite or bacteria infects the animal and compromises the immune system, which leads to a secondary bacterial infection that ultimately kills the animal.
Raimondi said it shouldn’t be long before scientists isolated the responsible pathogen. “We should know pretty soon,” he said.
MUKILTEO, Wash. — Near the ferry docks on Puget Sound, a group of scientists and volunteer divers shimmy into suits and double-check their air tanks.
They move with the urgency of a group on a mission. And they are. They’re trying to solve a marine mystery.
“We need to collect sick ones as well as individuals that appear healthy,” Ben Miner tells the divers as they head into the water.
Miner is a biology professor at Western Washington University. He studies how environmental changes affect marine life. He’s conducting experiments in hopes of figuring out how and why starfish — or sea stars, as scientists prefer to call the echinoderms — are wasting away by the tens of thousands up and down North America’s Pacific shores.
Watch the video report:
Scientists first started noticing sick and dying sea stars last summer at a place called Starfish Point on Washington’s Olympic Peninsula. Then reports came from the Vancouver Aquarium in British Columbia, where diver biologists discovered sea stars in Vancouver Harbour and Howe Sound dying by the thousands.
It’s been coined “sea star wasting syndrome” because of how quickly the stars deteriorate. Reports have since surfaced from Alaska to as far south as San Diego, raising questions of whether this die-off is an indicator of a larger problem.
“It certainly suggests that those ecosystems are not healthy,” Miner said. “To have diseases that can affect that many species, that widespread is, I think is just scary.”
At first only a certain subtidal species, Pycnopodia helianthoides, also known as the sunflower star, seemed to be affected. Within a day or two of showing symptoms, the fat, multi-armed stars melted into piles of mush.
Then it hit another species, Pisaster ochraceus, or the common, intertidal ochre star. Then another. In all, about a dozen species of sea stars are dying along the West Coast. Sea star wasting has also been reported at sites off the coast of Rhode Island and North Carolina. But researchers say until they’ve identified the cause of the West Coast die-offs, they can’t confirm any connection between these outbreaks.
Scene From A Horror Film
Scuba diver Laura James was one of the first to notice and alert scientists when the morning sun star, Solaster dawsoni, and the striped sun star, Solaster stimpsoni, began washing up on the shores of Puget Sound near her home in West Seattle.
“I thought, ‘This is just getting a little too close for comfort, I need to go see what’s going on. And I need to document it,’” said James, an underwater videographer.
Laura James dives to film starfish die-offs in Seattle. Credit: Katie Campbell
“There were just bodies everywhere,” James said. “There were just splats. It looked like somebody had taken a laser gun and just zapped them and they just vaporized.”
She returned the site weekly, tracking the body count. At first, young stars seemed to be hanging on, a sign of hope that the next generation might be spared, but then even the smallest succumbed.
James has been diving in Puget Sound for more than two decades and says she’s never seen anything like it.
“People always ask me, ‘Do you see any big difference between now and when you started?’” she said. “I’ve seen some subtle differences, but this is the change of my lifetime.”
Reports from recreational divers like James have made it possible for scientists to track the ebb and flow of the syndrome. That’s what led Miner and his dive team to Mukilteo — a place where sea stars showing initial symptoms could be gathered.
“It turns out that you just need a lot of people out looking to be able to detect the spread,” Miner said.
Miner’s team surfaced, laden with 20 giant orange sunflower stars. They gathered stars that appeared healthy and others that had lesions and weren’t acting normal -— unnaturally twisting their arms into knots.
Miner trucked the stars to an aquarium-filled lab and placed one sickly star in with one healthy looking star. He also set up tanks containing only healthy-looking stars for comparison.
Then he watched to see what would happen.
Two sea stars share a tank, one healthy looking and one dying. Credit: Katie Campbell
Within a few hours, the sick stars started ripping themselves apart. The arms crawled in opposite directions tearing away from the body. While starfish have the ability to lose their arms as a form of defense, these starfish were too sick to regenerate their arms. Their innards spilled out and they died within 24 hours.
As for the healthy looking stars, Miner said they didn’t show symptoms anymore rapidly by being in the same tank with sickly stars.
A few weeks later divers returned to Mukilteo to find that most of the sea stars there have died. Miner concluded that all of the stars his team had collected were likely already infected just experiencing varying stages of illness. His team has since continued other infectiousness experiments collecting stars from other areas of Puget Sound where the disease hadn’t yet surfaced.
One such place was San Juan Island, part of an archipelago in the marine waters of Washington and British Columbia.
An Opportunity For Science
“We’re holding steady here and we’re not sure why,” said Drew Harvell, a marine epidemiologist from Cornell University who has studied marine diseases for 20 years. She teaches an infectious marine disease course at the University of Washington’s Friday Harbor Labs on San Juan Island and was at the labs when the disease broke.
Harvell immediately recognized the die-offs as an important opportunity for science. Marine organisms are often plagued by disease outbreaks, she explained, but seldom are scientists able to identify the exact cause.
“We have a problem of surveillance for disease in the ocean because they’re out of sight and out of mind,” Harvell said.
For the past few months, Harvell has been coordinating a network of scientists on both coasts who received rapid response funding from the National Science Foundation to investigate the die-offs. The team has established a website and map run by Pete Raimondi from the University of California Santa Cruz. It’s one of the fastest-ever mobilizations of research around a marine epidemic.
“This is an opportunity for understanding more about the transmission and rates of disease in the ocean, so it’s important that we gather the right kinds of data,” Harvell said.
In her lab, Harvell anesthetizes a healthy sea star before cutting off one of its arms and slipping it into a sterile bag. She’s sending samples to Cornell where her colleague Ian Hewson, a microbial biologist, will compare them with samples of sick sea stars from along the West Coast.
Using cutting-edge DNA sequencing and metagenomics, Hewson is analyzing the samples for viruses as well as bacteria and other protozoa in order to pinpoint the infectious agent among countless possibilities.
“It’s like the matrix,” Hewson said. “We have to be very careful that we’re not identifying something that’s associated with the disease but not the cause.”
Ben Miner collects arms of dying starfish for lab analysis. Credit: Laura James
Ruling Out Possible Culprits
In the search for what’s causing this sea star die-off, it’s important for scientists to rule things out. Some have suggested that these die-offs could be linked to low oxygen levels in the water and environmental toxins entering the water through local runoff. Yet this seems unlikely, they say, because these conditions would normally impact a wider array of animals, not just sea stars.
Others have pointed out that marine die-offs in the past have been linked to larger environmental factors like climate change and ocean acidification. Warming waters and changing pH levels can weaken the immune systems of marine organisms including sea stars, making them more susceptible to infection.
Some have asked whether radiation or tsunami debris associated with the Fukushima disaster could be behind this die-off. But scientists now see Fukushima as an unlikely culprit because the die-offs are patchy, popping up in certain places like Seattle and Santa Barbara and not in others, such as coastal Oregon, where wasting has only been reported at one location.
Others have wondered if a pathogen from the other side of the world may have hitched a ride in the ballast water of ocean-going ships. Scientists say this fits with the fact that many of the hot spots have appeared along major shipping routes. However, the starfish in quiet Monterey Bay, Calif. have been hit hard, whereas San Francisco’s starfish are holding strong.
But at this point, there’s no evidence to entirely confirm or entirely rule out these hypotheses.
A Sea Without Stars
Sea stars are voracious predators, like lions on the seafloor. They gobble up mussels, clams, sea cucumbers, crab and even other starfish. That’s why they’re called a keystone species, meaning they have a disproportionate impact on an ecosystem, shaping the biodiversity of the seascape.
“These are ecologically important species,” Harvell said. “To remove them changes the entire dynamics of the marine ecosystem. When you lose this many sea stars it will certainly change the seascape underneath our waters.”
Because the die-offs are patchy, scientists aren’t concerned that sea stars will be wiped out entirely. But there’s no end in sight and the disease continues to spread.
“We may still be at the very early stages of this. We don’t really know,” Harvell said. “But it’s as important as ever right now, that we’re monitoring to know where the disease hasn’t been yet and when it first hits.”
New experiments in Washington state started this week to test possible infectious agents. The network of scientists collaborating on this project hope to make an announcement in a few months.