Video: Loss of Reef Urchins

Scripps scientists Katie Cramer and Richard Norris describe in a new video how overfishing of predatory fishes such as grouper and snapper in the Caribbean set off a chain reaction which has caused the health of coral reefs to deteriorate.

The researchers documented in the May issue of the journal Ecography the poor recovery of a certain sea urchin after a catastrophic event. Long-spined sea urchins, known as Diadema antillarum, were once found everywhere on Caribbean reefs, until 1983, when an unknown pathogen rapidly spread throughout the region, killing 90 percent of the species within a year. These urchins are an important part of reef ecosystems since they eat algae that accumulate on corals. Many Caribbean reefs have become overgrown with algae since the die-off.

Related Video: Loss of Reef Urchins