[Sickened and diseased sea stars off the North America including the sunflower sea star]
Alyssa Gehman (interview): “So sea stars when they’re looking healthy have sort of puffy arms they’re sort of straight out they might curl or turn a bit. But when they’re sick they start to just curl back on themselves so they look very twisty. They get lesions so you can see what the lesion looks like on their surface, then their arms actually fall off and walk away, so it’s pretty noticeable when it happens, and that first disease outbreak in particular it hit sunflower stars which they are, they seem to be our most susceptible ones and we had these huge losses so they’re now listed as critically endangered, we’ve lost over 90% of their population from Mexico to Alaska which is over 5 billion sea stars might be over 6 billion, it’s so many.”
[Large sea star on the seabed]
Melanie Prentice (interview): “So we did the challenge experiments having our healthy sea stars and our wasting sea stars and we were collecting coelomic fluid samples throughout those experiments which again is like the sea star blood and then we used genomic data sets. So we did a bunch of sequencing from those samples and that’s what allowed us to characterise all the different bacteria and viruses within those samples and that’s where we first identified our pathogen Vibrio pectenicida and then from there, we essentially collected coelomic fluid from a wasting sea star and then all the culturing work to isolate that particular bacteria.”
[Sea star in sink in laboratory]
[Lab technician working on a sea star]
[Sample in Petri dish]
[Sunflower sea star in a tank]
[People working with samples in the lab]
[Sea star in a container]
Melanie Prentice (interview): “What we’ve detected is essentially a new strain, which is kind of like a different genetic variant of an existing species. So the species Vibrio pectenicida as a whole had already been identified in the early 90s in France. And it was isolated from scallop farms where they were seeing these mortality events and so they were interested in isolating the bacteria responsible. And they showed that this Vibrio pectenicida can cause mortality in scallop and oyster larvae, which is kind of like the little seed that the bivalves grow from. And so we’re dealing with the same species with sea star wasting disease, but we’ve characterised a novel strain here on the West Coast that’s causing disease in sea stars. So it’s just a slightly different genetic variant.”
[Sunflower sea star on ocean bed]
[Purple-colored sea star on ocean bed]
[Less healthy sea stars]
Rebecca Vega Thurber (interview): “In the past, we had no reason necessarily to believe, I would say in the way past, like in the early stages of the disease outbreak in 2013, 2014, people looked and they didn’t see anything. So they thought it must be something else like a virus or some sort of environmental physiological effect.”
[Sea stars]
[Divers looking at healthy sunflower sea star]
[Sea stars on the ocean bed]
This script was provided by The Associated Press.