'Wasting' Stars...

Low tide on Neptune Beach, Oregon coast

A trip to the beach would not be complete without looking in tidepools for sea stars or starfish, as many of us called them when we were children.  David and I have been doing our share of ‘tidepooling’ since we have been on the Oregon coast and now, in Washington.  Many wonderful creatures such as sea anemones, sea urchins, chitons, mussels, barnacles and crabs just to mention a few can be found in tidepools.  But this summer sea stars have been on our mind because they are dying in massive numbers from Canada to Mexico from a disease called Sea Star Wasting Syndrome.

 

Ochre sea star and green sea anemones

 

Large crab stranded in tidepool

 

Green sea anemone, "Tidepool Eyes"

 

We had heard about Wasting Syndrome a few months ago on National Public Radio.  Sea stars all over the world are being affected and west coast sea stars are dying in record numbers.  Wasting Syndrome starts with lesions on the sea star. Then, in as soon as a few days, the Sea Stars start to almost ‘melt,’ losing their shape and often limbs fall off.  The syndrome has been around for some time but usually it is a summertime or warm water disease and plays out quickly especially once the seasons change and the sea waters cool. 




Ochre sea stars can be orange, brown, purple or reddish

Ochre sea star with white lesions



The past two years it has been a different story.  The oceans are warming and staying warmer so the disease is not letting up.  Even many captive populations like aquariums that pipe in fresh sea water are being hit hard by the disease.  It is not certain exactly what causes Sea Star Wasting Syndrome.  Probably it is a virus or bacteria but whether it is in the sea water or maybe somewhere in the food chain, perhaps the mussels that are the main diet of Sea Stars, no one knows yet.  What is certain is that the Sea Stars are stressed by the warmer ocean temperatures and this is making them more vulnerable to the disease.

 

"Melted" ochre sea star, probably dead

 

Detached limb

 

So far, the Oregon sea star populations have not experienced the massive die-offs that have affected many sites in Washington and California.  But there are more reports of the disease in Oregon as the summer goes on.  We have seen healthy sea stars in our tide pool searches but we have also seen a few with lesions, detached limbs, sea stars that look like they are ‘melting’ and a few dead ones too.  Not being scientists and not being that familiar with the disease we can’t be absolutely positive that we’ve seen ‘wasting’ sea stars.  But based on our observations it sure appears that some of the sea stars we’ve seen are expressing symptoms of the disease.

 

Two species of mussels, a favorite meal of sea stars

 

 

In some tidepools, the ochre sea star and the sun star are ‘keystone’ species, meaning there are so many of them that they have a huge influence over the populations of other creatures in the tidepools.  So as sea star numbers plummet, the ecosystem of tidepools may be greatly changed.  The next time you wish upon a star, send good wishes for the sea stars…