A STARring Role

A STARring Role

STARFISH-WEB

by Lucas Basulto

It sounds like something out of a horror movie. You develop white lesions that begin to decay and become holes in your flesh just before your arms and legs fall off. This may sound like science fiction, but for our local sea stars, this is sadly science fact.

Jana Litt, a marine biology graduate student at Humboldt State, is studying Sea Star Wasting Disease in ochre star populations from an entirely new vantage point.

Litt is studying how the disease progresses through our wild populations and affects individuals. By following individual sea stars in the field throughout the progression of the disease, Litt is doing something new and innovative in her field.

According to Robert Paine, professor emeritus at the University of Washington, the Ochre Star is an important “keystone” predator of the rocky intertidal ecosystem.

“They consume mussels like they’re going out of style,” Litt said.

A “keystone” species is one that holds an important position in relation to the overall health of the ecosystem in which it lives. When these species begin to decline or disappear in the ecosystem, the food web becomes unbalanced and eventually collapses; much like a stone arch would if you removed the stone at the top center, its “keystone”.

Ochre stars keep the mussel population down within the rocky intertidal ecosystem. This might not seem like a big deal to us here on dry land, but too many mussels does come with a cost.

“If mussel beds are allowed to grow unchecked, then we eventually end up with an ecosystem that can’t sustain fish at the end of it all,” Litt said.

Ochre stars play a key role in their ecosystem but they also serve a dual purpose. These stars also act as an “indicator” species or an animal that can be observed to assess the overall health of the environment.

The disease itself is caused by a virus. The Sea Star Densovirus (SSaDV) is possibly spread through the food and sediment in which the star is in contact with showing some similarities to the chickenpox virus that humans are sometimes exposed to.  

An ochre sea star (Pisaster ochraceus) suffering the effects of Sea Star Wasting Disease (SSWD), which includes loss of limbs and white sores on the outer layer of skin. | Photo provided by Jana Litt
An ochre sea star (Pisaster ochraceus) suffering the effects of Sea Star Wasting Disease (SSWD), which includes loss of limbs and white sores on the outer layer of skin. | Photo provided by Jana Litt

“It’s like the shingles,” Litt said. “Not everyone gets it but it is out there, and it is awful.”

Symptoms of the disease include lesions (white patches) on the epidermis or “skin” of the sea star.

Sea stars are water vascular organisms, meaning their bodies function on the hydraulic pressure within them. If this system is punctured, then a lot can go wrong for the stars. Since they rely on their internal pressure to move, a hole in their body means that they can no longer move around and hunt for food.

If lesions worsen, they can become perforations in the star, allowing it’s internal organs to exit their body cavity

Stress on sea stars is also a contributing factor to the spread of the disease; something that us as students can relate to this time of year.

“Stress causes disease; we all know that,” Litt said

Around this time during the school year, you may notice more and more students falling ill. As students, particularly during finals, we are much more likely to get sick simply because we are stressed out. Sea stars are subject to this same issue.

Our stresses as students may be wondering if we studied enough, or finishing that huge stack of homework you still have to do. Sea stars experience temperature stress, an issue we face with global climate change and the rising temperature of earth’s oceans.

“It’s terrifying to think that in some places there is a higher risk for extinction because of the loss of numerous stars and star species,” Litt said.

Litt is conducting her research between Trinidad and Crescent City, but says that Sea Star Wasting Disease is something that is affecting sea stars throughout the west coast of North America. She relies on the help of undergraduate volunteers to aid her in data collection necessary to her research.

“I’m incredibly grateful to all of the volunteers who are dedicated to collecting data for this research,” Litt said. “I couldn’t do it without them.”

The volunteers that assist Litt are a dedicated bunch, getting up at 2 a.m. to head to the intertidal zone.

“They do it with a smile,” Litt said.

Melissa Castellon, one of Litt’s volunteer team leads, plays an important role in making sure that everything is ready to go before the research begins.

“We help set up transects,” she said. “I make sure we have all the equipment we need.”

Team leaders like Melissa are also responsible for training new volunteers and making sure everything gets taken care of before heading to the field.

“My team leaders know what I need even before I do. I love them for that,” Litt said.

There is still a lot to learn about SSaDV but Litt is optimistic about a brighter future for these icons of the ocean.

“We are not seeing as many symptomatic stars now as we were seeing in 2013 and 2014,” Litt said.

Opportunities for undergraduates to aid in research like this are an important milestone in becoming a field researcher or graduate student and Litt’s volunteers seem to realize that.

“I feel really lucky to get the hands on experience and even luckier to be working with an amazing marine biologist like Jana,” Castellon said.

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