A common bacteria called Vibrio pectenicida has been around for ages, though few knew about it. It causes Sea Stars to become ill and waste away, appearing almost as if they had melted, a condition appropriately named Sea Star Wasting Disease.

Usually, the sea stars have some resistance to the bacteria, which is one of over 50,000 identified in sea star blood, so its toll on the Sea Star population has been negligible. But that began to change in 2013. In that year, sea stars were dying in droves in the waters off Washington state. It effected more than 20 species of Sea Star with the Sunflower Sea Star (Pycnopodia helianthoides) taking the brunt of the epidemic.

The following year was better off the coast of Washington, but the disease was found flourishing in other parts of the coastal pacific. Since then, it has gained strength so that today the Sea Star population is a small fraction of what it was. The sunflower sea star population has dropped by an estimated 90% globally since 2013.

It is only recently that scientists have identified Vibrio pectenicida as the likely culprit.

SO, WHAT CHANGED?

Records show that the ocean temperatures have been slowly increasing since at least 1990, which is when we started tracking it. They are still studying the mechanisms involved but this is a reasonable assumption given the known data. Like most bacteria warmer temperatures increase the metabolism of Vibrio pectenicida. It grows faster, multiplies faster, assuming it has enough food, and it kills faster. In the meantime, the starfish is already using most of its available resources. A faster metabolism would cause it to need more food, which isn't available. The starfish is now undernourished, but there are other forces at play. Starfish would also suffer from the fact that warmer water holds less oxygen. This would have little effect on the bacteria but weakens the starfish enough that his system can no longer effectively fight off the bacterial infection. Hence, warmer waters have made what was a minor problem into a devastating one.

BUT IT GETS WORSE

The favorite food of the Sunflower Sea Star is the Purple Sea Urchin

and the Starfish is a major control to the Purple Sea Urchin population so with the Starfish population decimated, the Sea Urchin population have exploded. To make matters more complicated, the Sea Otter (Enhydra lutris), which also eats sea urchins, has suffered its own population decline. Scientists aren't yet sure what the current Sea Otter problem is but it's likely related to an increase on Orca (Orcinus orca) sightings in the same areas.

In any case, the Sea Urchin population boom is just the next step in the chain because the Purple Sea Urchin is one of the main predators of the Pacific Kelp Forests. 

 With the Sea Urchin population boom, the Kelp forests are disappearing. And in the typically interconnected way that nature works, a decline in kelp forest populations accelerates global warming by reducing the ocean's ability to absorb atmospheric carbon dioxide (CO2).

THE NEXT CHAPTER?

While the sea stars' collapse echoes a sobering tragedy, the recent breakthrough identifying Vibrio pectenicida strain FHCF-3 as the driver of the wasting disease ignites a ray of hope. For the first time, scientists are not just witnesses to the devastation — they now have a target for monitoring, breeding resilience, and ecosystem restoration. *

By cultivating disease-resistant starfish, exploring probiotic or phage interventions, and safeguarding kelp forests through community-led marine stewardship, we can begin to heal the wounds of decay. The fate of the kelp forest, the fish, the otters — and ultimately, our planet’s climate resilience — depend on the ripple of these efforts.

In the story of the melting starfish, let’s not only lament what was lost, but also ignite what can be rebuilt. The next chapter is still ours to write.