The Quarantine Scene

Last week, we told the story of a mysterious sea star that may have literally fallen out of the sky and into our lives. With continuing bad news about Sea Star Wasting Disorder, Animal Care staff had recently implemented a quarantine protocol for new animals going into our tide pool touch tank. Our recent visitor was a good test for our new procedure.


The original home of our animals, Puget Sound, is cold – from 8 degrees (44˚F) in winter, to 14 degrees (57˚F) in late summer. Naturally, our touch tank animals need cold water to stay healthy. The price of chillers, a machine that cools and recirculates tank water, is expensive. But we realized we could use a small refrigerator and modify it with a thermostat to bring the temperature within the required range for the health of our tide pool animals.

Once we fitted our fridge with containers for the types of animals we would be housing, we created a manifold of air bubblers to keep the animals’ water well oxygenated. Each day we do a 50% water change, using synthetic sea salt mix. By changing out the water, we dilute and over time flush out any pollutants the animals have in their bodies. The frequent, large water changes also mean the tanks never accumulate toxins such as ammonia, and if we remove the water with care, we clean up most of the waste and uneaten food at the same time.

Our quarantine process has worked very well as a temporary life support system, but as a method for preventing Sea Star Wasting Disorder it has one obvious flaw: If any animal other than a sea star is a carrier, it will not show any symptoms. Therefore, there is no obvious way to determine if an animal is safe to be around our stars.

Somewhat arbitrarily, we hold wild-collected animals for 30 days regardless of species, and those transferred from other facilities for a variable amount of time. Anemones are mostly water. Ten days of 50% water change should lead to them trading out most of their native water for new, ‘clean’ synthetic water mix. Other echinoderms, such as urchins, are not thought to be carriers but are quarantined longer than anemones simply because of their closer relationship to the sea stars.

And what about new sea stars? Our intention had been not to introduce any. But when one was brought to us, we determined that 30 days should be enough time to see if symptoms developed. Sadly, we didn’t need even ten days. We do not know if our little star succumbed to wasting disorder, or to the trauma of being removed from the water and attacked by gulls. Our quarantine care could not help it. The star showed lack of motor control, loss of body substance, and eventually its limbs began to deteriorate. At that point, Animal Care gave it a swift and humane end of life.

We are sorry to lose the star, but grateful to volunteer David Ashlin and Animal Caretaker Katie Malmberg for recognizing that this animal was not a resident of our touch tank. And a big “Thank you” to Christopher Russell for developing our quarantine process that lets us prevents problems before they entered our tide pool system.


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How Are Our Sea Stars Doing?

Many visitors to Pacific Science Center have been asking about a current ecological phenomenon known as Sea Star Wasting Syndrome. Have our Puget Sound Salt Water Tide Pool sea stars been affected?

The short answer is “No” and we are monitoring the situation closely. Pacific Science Center addresses the disease here including links to current research. Be assured that Animal Caretakers are recording any unusual appearances and movements of our sea stars in the hopes of having early detection if the disorder does appear. We are also taking photographs regularly and logging instances when staff report concerns about possible skin integrity.

The normal, relaxed posture of a sea star is open, like a star – with all limbs pointing straight out. The arms of sea stars contain sensory organs as well as the tube feet they use for movement. By spreading out their arms, they have access to the most sense data. But once in a while, the stars will take other postures.

Because crossed and twisted arms are an early indicator of the wasting disease, we are recording every time a star is noted in one of these positions. This will give us a good baseline for how often a healthy star is in one of these positions.

Sea star wasting syndrome is characterized by lesions of the skin – discolored, broken, or whitish areas where the epidermis has begun to break down. The white, calcium rich plates and spines of its skeleton become more obvious through its skin. But a sea star looks very different when it sits at or above the water’s surface than it does below. So far all our calls have been for stars that have parts of their body above the water level, and look funny but are actually fine.

We’ve also received few calls about the madreporite of our sea stars. This hard calcium ‘button’ on the top of every sea star is used to control the water pressure in and outside of the animal. Many people have never noticed the madreporite before, and wondered if it might be a sign of problems. We are fortunate to have many new eyes help us monitor our animals.

As more information is learned about this phenomenon, we will be reporting our findings. Until more is known, we will not be introducing any new sea stars or their relatives into the tide pool.


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