Reported sea urchin die-off in Caribbean could imperil coral reefs

An organization that monitors reefs in the Atlantic and Gulf is warning that the Caribbean appears to be facing a rapid widespread long-spined sea urchin die-off extending more than a thousand miles, from the U.S. Virgin Islands to Jamaica, possibly beyond.

Driving the news: A group called Atlantic and Gulf Rapid Reef Assessment says the first reports of extensive urchin die-offs came in mid-February from Charlotte Amalie Harbor in St. Thomas.

• By the end of March, die-offs were reported in St. John, Saba, St. Eustatius, Dominica, St. Vincent, and Jamaica.

Why it matters: Long-spined sea urchins scour over coral, eating harmful algae and giving reefs open space to grow.

• Diadema antillarum are so important that researchers at the Florida Aquarium in Tampa last year reared and released nearly 200 long-spined sea urchins off the East Coast to help clean the Florida Reef, which stretches from the Dry Tortugas to Palm Beach.
• The project — with the Center for Conservation, the University of Florida and the Florida Fish and Wildlife Conservation Commission — is considered the largest known urchin restocking effort in the last 20 years.

Flashback: These long-spined urchins were once abundant in the Caribbean, but we lost nearly the entire population in the early 1980s due to an unknown disease. The population has not fully recovered.

• Researchers have hoped that breeding and releasing urchins would help restore reefs that are dying off at an alarming rate due to climate change. Similar urchin efforts have been happening in places like St. Eustatius and Saba.

Of note: No die-offs have been reported in Florida waters. Several healthy urchin sightings were reported in late March.

What they're saying: "While we do not know what is causing these dispersed die-offs, the speed at which large numbers of sick urchins are now dying on affected reefs resembles the mass mortality event of four decades ago," the AGRRA said in a statement.

• "We worry that a real crisis is developing in the Caribbean, where stony coral tissue loss disease has already caused widespread coral losses affecting about 34 coral species in 20 countries/territories."

What's next: The Diadema Response Network is asking for volunteers to help report healthy and unhealthy sea urchins using this form.