Did you know Diadema previously experienced a massive die-off throughout the Caribbean in the early 1980s?

A waterborne pathogen beginning near the Atlantic Panama Canal entrance caused history's largest recorded marine animal die-off, wiping out 95-99% of Diadema antillarum populations throughout the Caribbean. The demise of this herbivore contributed to a phase shift of Caribbean reefs from coral-dominated to alga-dominated communities. On the average the current population densities are approximately 12% of those before the die-off.

It started happening again last winter and scientists are concerned because the pace at which the urchins are dying could rival the mass die-off that last occurred in 1983, alarming many who warn the trend could further decimate already frail coral reefs in the region.

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.

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 stress by warmer-than-average ocean temperatures and a disease known as stony coral tissue loss.