From Mendocino County Public Broadcasting, this is the KZYX news for Friday, February 26th. I’m Lana Cohen.
“Well first if I can just tell you about the sunflower sea star and just how cool of a species it is in and of itself.”
That’s Walter Heady, he’s a coastal marine ecologist for the California Chapter of the Nature Conservancy, an international national non profit.
“Sunflower sea stars are one of the largest sea stars in the world. They can grow to be over three feet in diameter. They have about 20 arms, with thousands of little tube feet under them which help them to sense the world as well as to move along the seafloor as one of the fastest sea stars in the world. They can move about six feet a minute. Which is not terribly fast compared to a cheetah, but it’s actually a very fast moving sea star to the point where you can see them move across the floor. So they are a charismatic invertebrate in the marine world.”
These giant sea stars are in trouble. A study published by the Nature Conservancy, Oregon State University, and other partners found that 5.75 billion sunflower sea stars, which is 90% of the species previous population, have perished since 2013.
What happened to the sunflower sea stars is not a pretty story. Basically, climate change led to warmer ocean temperatures, which gave way to an unprecedented virus called sea star wasting syndrome. Heady, one of the authors of the study, said it was early last decade that he first started noticing the struggling sea stars.
“We started noticing disease outbreaks where these individual sea stars would grow lesions and get sick and literally waste away. Some other folks have described that they turn into goop. They literally dissolve in the either intertidal or sea floor area. And we started noticing that that was happening widespread in a high number of stars and a number of different species and it really started to impact the sunflower sea stars in their range from Mexico up into Alaska.”
Sea star wasting is a heartbreaking, graphic, and kind of a gory disease. Honestly, it seems more like something that would happen in a sci-fi movie or on an alien planet rather than here on planet earth. The first time local biologist Tristin McHugh saw a wasting sea star was in 2013 near Monterey.
“I remember seeing a sea star with a physical lesion, like a cut, on its arm. There are many different forms that you can see a sea star wasting in like the cut, the loss of an arm, it detaching and the most severe is it physically melting and in between that you also would see twisting arms and them physically rejecting their body, like contorting their arms into pulling them off.”
The loss of the sunflower sea star has decimated ecosystems all across the species range and a local marine biologist, Tristin McHugh, said that holds true here in Mendocino.
“The loss of sunflower stars in Mendocino and the North Coast has been very impactful on the balance of the kelp forest ecosystem and ultimately to our community.” McHugh is the Nature Conservancy’s North Coast kelp project director.
“You know everyone in the community is keenly aware of what’s going on with kelp forests and everything we’ve been talking about when it comes to kelp loss, the boom in purple urchin, the loss of the abalone fishery, the federal disaster to the red urchin fishery and the cultural and aesthetic loss of these forests, but it’s all tied to the disappearance of the star.”
The disappearance of the sea star in tandem with warmer water temperatures triggered a chain of events which ultimately resulted in the collapse of multiple local fisheries. Fisheries that have historically played important cultural and economic roles in Mendocino. This includes the red urchin and abalone fisheries, which, before they collapsed, could bring in up to 3 million and 44 million dollars in annual revenue to the county’s economy, respectively.
So Here’s what happened: the sea star was the last remaining predator of purple urchin. And purple urchin, they eat kelp, which are big brown algae that grow in groups and create dense underwater forests, providing food and shelter to nearshore marine life. When the sea star numbers plummeted, the purple urchin population exploded. And the urchin ate so much kelp that the forest disappeared. So then, all the species that relied on the forest for shelter and food, such as red urchin, abalone and a variety of fish species were left empty handed.
Noticing the rapid decline of sunflower sea stars, scientists from the Nature Conservancy, Oregon State University and other partners decided to find out just how many sea stars were left. When they realized that over 90% of the population was gone they came to the conclusion that the sunflower star was critically endangered.
They submitted their findings to the International Union for the Conservation of Nature,IUCN, for short, which is a nonprofit dedicated to conservation and sustainable development across the planet. The IUCN agreed with their assessment and listed the species as critically endangered on their Red List, an international list of species threatened with extinction.
Heady hopes that this categorization will bring attention to the plight of the sunflower starfish.
“There’s a number of different rankings on the IUCN Red List site and critically endangered is one step away from extinct. So it’s dire is what it means. It means that we’re really at risk for extinction of the species without concerted action.”
The IUCN listing doesn't give the species or their habitat any legal protections the way that a federal or state listing would, but Heady and McHugh said they hope it will bring attention to the decline of the species and encourage support for research through public interest and funding.
McHugh said now that the sunflower sea star is listed, scientists are working to figure out how to help out the struggling species which continues to be pummeled by sea star wasting disease and the impacts of climate change.
“That’s currently being explored right now with researchers from University of Washington and the Nature Conservancy, is exploring captive breeding programs. Can you actually have these animals reproduce in a lab setting and if so, after you go through all the mechanisms of outplanting the species is it something that is actually needed and is it appropriate.”
For KZYX news, I’m Lana Cohen.
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