From the Field

Sick Sea Stars and Starless Nights

February 4, 2014

A sick ochre star surrounded by apparently healthy ones from Olympic National Park. Photo: Steve Fradkin

By Drew Harvell and Laura James

In World War Z, a super- transmissible virus that turns humans into twisted, rabid zombies spreads freakishly fast across the globe.

In terms of real human diseases, the Spanish Flu of 1918 was the most devastating in a global spread, killing 10% of the world’s population.

Sea stars along both coasts of the US have been struck by a massive, extremely virulent mass mortality.

It is currently sweeping along the west coast and affecting both our most abundant species like the sunflower star and ochre star and a series of 10 other species as reported in by the monitoring group MARINEe (based at UC Santa Cruz).

Although our sick stars are not rabid and biting each other, the syndrome is called sea star wasting because they become deflated, lose skeletal ossicles and develop lesions in the body wall.

Then their arms become twisted and drop off. Like the zombie virus, when it hits some areas, the sea stars drop dead very quickly, (as we’ll describe from Alki Beach, Seattle).

In the movie version of the human zombie virus, a person was bitten and showed “zombie symptoms” 10 seconds later. The disease transmission picture is not so clear for sea stars.

In the sea star event we still lack clear evidence for a route of transmission, even though it seems so likely to have an infectious cause.

Scientists think this is caused by an infectious agent because:

1)    new cases appear at different times and locations along the coast, starting last June in Olympic National Park.

2) In the Seattle Aquarium, stars in UV filtered water, which would kill viruses or  bacteria, survived and others died.

3) At some locations, the spread to new unaffected stars takes a few days and appears to move as a wave.

4) Molecular typing shows bacteria and viruses in the sick animals that are not present in healthy.

Work is underway at Cornell to confirm and test the sequence of bacteria and viruses present in the sick that are not present in most healthy stars.

Scientists are also perplexed by the timing of the sea star event this fall. It did not correspond with unusually warm or unusually cold conditions, or cold upwelling or low oxygen conditions.

In some places like the Northwest, there were big mortality events near urban places like Vancouver and Seattle. But more pristine locations like on the outer coast of Vancouver Island, in Olympic National Park and in central California also experienced big mortality events.

There are hints at some sites that low salinity might be associated with sickness. This makes sense because sea stars are unusual in having no kidneys and have no ability to regulate their inner salinity levels.

We speculate freshwater inputs could either facilitate disease through stress or even convey infectious agents in freshwater run-off.

 A Horrifying Personal Look at Sea Star Collapse

This is by far the largest Pacific coast-wide sea star disease event that scientists have recorded. We’d like to recount the story from a single site: Alki Beach, Seattle.

Laura James tells me one of the best dives around Puget Sound is right across from downtown Seattle.  It’s a place filled with cool stuff like giant pacific octopus, small red east pacific octopus, seals and, once upon a time, 8 species of sea star.

When she dove there last summer, Cove 1 was a teeming star-filled galaxy: sunflower stars of all sizes scavenging, morning sun stars chasing the occasional rose star, mottled stars, brittle stars, vermillion stars, blood stars, striped sun stars. And more.

On November 12, Laura dove there and witnessed a scene from a horror film and you can see this on her accompanying video.

Sea stars of three species are sick, hanging from a few tube feet attached to pilings or fallen dead underneath. Some stars so far gone that only an arm or two was left hanging.

Underneath, the pilings were surrounded by hundreds of decomposing stars. On the December 14 evening low tide, just after leaving the Conservancy’s All Science meeting, I joined Laura and we were surprised to find 130 live ochre stars hidden away high in the intertidal above the continuing devastation in the subtidal.

About half of these had signs of illness such as contorted arms, lesions all the way through their body, and slack non-gripping tube feet. These tube feet were once powerful enough to open a mussel by brute force.

This week, Laura dove once again in Cove 1 to collect stars for our experiments to decipher the causative microorganism.  On this night, there was only a single star here and there.

Pilings that held hundreds of stars before the outbreak were now almost completely barren, adding up to a body count of several thousand at just this one site.  The remaining few were in various states of disease.

It was a terribly poignant last film that Laura shot of this site, joined in silent witness by a curious seal, along to help.

I am at once extremely interested and driven to unravel the mystery of this die-off, because it is iconic of the knowledge gap we have about how disease propagates in the ocean.

At the same time, I am personally devastated by the loss of so many sea stars, from so many different species.

I am hoping that the locations of the mortality events are patchy enough, with healthy stars left in places, that we do not yet have to fear extinction.

But these are top keystone, ecologically important species and their loss will have an impact. And I still feel like my own highly treasured biodiversity of our most iconic invertebrate species is being robbed, and each continuing mortality event in this continuing epidemic worries me.

If this were a real zombie virus affecting humans, we would have massive resources at our disposal to figure out the pressing questions.

And yet many people act as if this huge epidemic affecting a keystone species in the ocean is simply a curiosity and a normal event in the oceans.

They assume scientists will figure it out. Scientists will not figure it out unless they have the funding and investment in infrastructure that is needed.

Our country is quite good at surveillance of disease in hospitals, the CDC is adept at identifying and typing new human disease and the USDA is good at monitoring terrestrial food safety. But who is providing enough funding to adequately monitor health and disease in the ocean?

This is just the latest in a series of new disease outbreaks in the ocean and we are terribly under-prepared. Just this year, we have had catastrophic losses of dolphins to disease and this major outbreak of sea star deaths on both coasts.

These outbreaks can be thought of as sentinels of changes we don’t understand in our oceans.

Join the Discussion

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  1. I was wondering if the bacteria and viruses are just opportunistic infections, and the original cause of failure of the seas stars is due to a new medication or pesticide, or fertilizer being used on land, or combination there of?

    1. A very good question. We hope that by identifying the causative microbe, we will be able to also learn if there are facilitators such as pesticides or fertilizers. The very large range of this makes local inputs less likely, but we cannot rule it out yet.

      1. I am the former manager of the aquarium at the Sitka Sound Science Center, and I first witnessed this wasting syndrome in several species of sea stars in 2007 in the center’s touch tanks. After putting mitigation measures into place, I believe that our event was a direct result of water chemistry (in short, the result of a pressure differential in our vacuum pressure-we get our water for our tanks straight from the ocean). I am curious about the apparent discharge at 04:39 in the film. Can you describe what that is? Please feel free to email me at my address. Regards.

  2. Has anyone researched a possible contaminant from the radioactive waste washing in from Japan? It seems to me that with all the items appearing on our coast from that event we may see many changes to our sea life that is catastrophic.

  3. We have pictures of massive colonies of stars from the coast near Ozette taken in the late 90’s. We have told our daughter stories of these natural wonder for years. We took her out for her first backpack trip to Sand point. There were no stars there in early September. None.
    I’d love to send you photos. What can we do to help?

    1. Erin, let us contact Drew and Laura to get their take on what specifically people can do to support research into these diseases outbreaks. We’ll report back in the comments.

  4. The sea star are such a beautiful creature, this is terrible that it is happening to them. I almost wonder if it is something similiar to what they call “Red Tide” that happens in Flordia. I know that more than just one species dies there though. Which leads me to wonder if there could be place like Power Plants or places that have toxins that could be leaking in to the water. If there are there could be a possibility that they could be causing this effect on the sea stars. I also feel like they should be checking all of the different levels in the water(pH,etc)to see if there are any levels spiking or dropping that could have an effect on them. I really hope they figure out what is causing this soon. I also hope it doesn’t start effecting the other animals or humans.

  5. Acid ocean?[30% > 1800 A.D. natural level]+ virus.
    Check if upwelling areas—less acidic deep water–are more immmune.

  6. Most people are so addicted to money and debt, they don’t think about much of anything else, until they themselves begin dropping dead from a new plague, when it’s too late
    to do anything but die.

  7. I fear that in the case of white nose in bats, some of the wildfire-fast geographic spread of the disease may have been caused by researchers not sterilizing their nets and other gear. I wonder what the divers are doing to make sure that their gear does not contribute to the spread of whatever pathogen is involved, here.

  8. […] Drew Harvell and diver Laura James wrote a blog post for the Nature Conservancy about the outbreak. In it, Harvell, who is one of the scientists doing genetic research on possible […]

  9. Last week I took my invertebrate zoology class on a field trip to the Palos Verde peninsula in Los Angeles, to a preserve where for 12 years I have always found hundreds of Pisaster sea stars; there was not a single one present. I was not aware this was a coast-wide epidemic until I saw your article. The brittlestars also showed an awful tendency to drop their arms and die immediately upon being picked up, which they would not normally do. A complete wipeout along the whole coast is incredibly hard to fathom, and will have dramatic ecological consequences.

  10. Thank you for your good work and powerful documentation. I think of Pisaster ochraceus in particular as a very tough animal so this die-off is shocking to me.

  11. I have a beach house in the southern Puget Sound on Harstine Island. We have always had many varieties of sea stars. I haven’t been up since last September, but will be there in a few days,I do not know if this die-off has hit our area yet. I am very saddened and alarmed about the future when such tough creatures have 100% mortality rate. Even the worst human flu outbreak on record had only 10% mortality rate!

  12. I have been involved in several of these mass mortally incidents in lobster, sea urchins and fish on both east and west coasts and appreciate the difficulty in sorting this out. Although I suspect that the usual suspects (vibrio sp) will pop up. I wonder if you had any updates on pathogens that might be involved. I wonder about the status or appearance of coelomic fluid on the sick vs healthy stars. In looking at sick urchins the fluids were almost devoid of cells, similar to “Bumper car” in lobster. In those cases a ciliate “Orchitophyra sp” was implicated. I note that Mah’s ectoderm blog has a discussion of this

  13. Is this problem affecting other echinoderms such as sea urchins/sand dollars, sea cucumbers, crinoids and blastoids (OOPS, scratch the last – we lost them after the Permian)? Might this be a small boon to corals being seriously predated by the “Crown of Thorns” monster?
    art wegweiser, Prof Emeritus (Geology)