The long-spined sea urchin’s (Diadema antillarum) population in the Caribbean has been devastated by a parasite.
Scientists investigating the serious die-off of the urchins first reported in St. Thomas in the U.S. Virgin Islands found that a parasite is responsible. Sadly the condition afflicting sea urchins has spread, and by June 2022, it was detected in Florida, Curacao and the Greater Antilles.
The mystery disease has been obliterating the sea urchin population, with some areas suffering from declines in numbers between 85% and 95%. An international team of 42 scientists has been investigating the illness and finally found that the culprit is Philaster apodigitiformis, a unicellular eukaryote.
Discussing the work, marine ecologist and professor of microbiology at Cornell University and lead author of the study Ian Hewson stated:
“Rarely are we afforded the opportunity to understand marine disease events in this detail, where we can actually work out a cause of it. Knowing the pathogen’s identity may also help mitigate risk to untouched Diadema through such things as boat traffic, dive gear, or other ways it may be moved around.”
Describing the investigative process, Hewson explained:
“They initially did not show any sort of unusual or candidate microorganisms at all. We were a bit at a dead end. Immediately when I did that, I had an enormous signal of this scuticociliate Philaster. I saw this ciliate was actually very, very abundant. That was the big ‘Ah ha’ moment.”