Concerned scientists probe sea urchin deaths in Caribbean

SAN JUAN, Puerto Rico (AP) — Sea urchins are dying across the Caribbean at a pace scientists say could rival a mass die-off that last occurred in 1983, alarming many who warn the trend could further decimate already frail coral reefs in the region.

Dive shops first began reporting the deaths in February, perplexing scientists and worrying government officials who are receiving a growing number of reports about dying sea urchins from islands including Antigua, St. Lucia, Dominica, Jamaica, St. Vincent, Saba and the U.S. Virgin Islands as well as Cozumel in Mexico.

“It’s very concerning, particularly because it’s happening so quickly,” said Patricia Kramer, a marine biologist and program director of the Atlantic and Gulf Rapid Reef Assessment, a scientific collaboration to improve reef conditions in the region.

At first, the mortality event was linked only to black sea urchins — diadema antillarum — which are recognizable by their extremely long, skinny spines. But two other species have since been affected, including the rock boring sea urchin and the West Indian sea egg.

The deaths worry Kramer and other scientists including Dana Wusinich-Mendez, Atlantic-Caribbean team lead for the U.S. National Oceanic and Atmospheric Administration’s coral reef conservation program: “Losing our sea urchins would be really devastating.”

The deaths are of concern because sea urchins are herbivores known for being efficient grazers that remove macro algae from coral reefs and clear space for baby sea corals to attach themselves, the two scientists said.

“They’re kind of the unsung heroes of the reefs because they do so many good things,” Kramer said.

While macro algae are an important source of food and shelter for some fish, too many of them can degrade coral reefs that are under...