Knobby Sea Star
Artist: Jane Kim/InkDwell

Warmer water temperatures, reduced ability to fight illness, pathogens passed on from shellfish – it’s not quite clear which of these, or maybe which combination is raging through the sea star populations of the United States West Coast. But the fact is that millions of sea stars from Alaska to Mexico are wasting away, suddenly and across a number of different species.

Sea stars feed on shellfish, and are apex predators of marine coastal environments – when they suffer, the entire ecosystem is affected. Many of the sea star species affected are endemic to their small regions; they aren’t found anywhere else in the world.

It’s not the first die-off that’s been observed among sea stars, but it’s by the far the largest in terms of geographical area and number of species affected. If the juvenile sea stars can manage to develop immunity to the current illness that is wiping out the adults, the populations will have a chance of eventual recovery. Researchers and citizen scientists up and down the coast observe, record and try to figure out the exact causes of what’s been labelled the sea star wasting syndrome.

The disease forms lesions on the sea star, which eventually cause the limbs to dissolve.
Sea star Pisaster ochraceus, the most commonly affected species, is pictured.
Photo : University of California, Santa Cruz, Dept. of Ecology and Evolutionary Biology

When I was a kid, we had a salt water aquarium that included a couple of starfish, now more commonly known as sea stars. But we could never get it quite right, and the poor creatures kept making extremely ill-conceived attempts to escape by climbing out of the tank at night. All we could do was pick up their desiccated forms in the morning. We gave up when the seahorses started hurling themselves on to the carpet. We never did quite figure out exactly what we were doing wrong.

As for the Pacific coast, my hope is that the future holds more promise than an increase in the kind of science taking place around sea stars right now – the monitoring and understanding of an extinction in progress.