Report: Dorian razed 30% of reefs in Bahamas

When Hurricane Dorian slammed into the Bahamas in September, it not only leveled entire communities and killed dozens of people, it also destroyed about 30% of the coral reefs around the islands, according to a report issued by the Perry Institute for Marine Science.

“We saw on several reefs that a significant amount of corals were broken, rolled around on the bottom and killed, or just smashed up to the point that the actual structure of the reef itself was reduced to rubble,” said Craig Dahlgren, lead researcher at the Perry Institute, which has been examining effects of the hurricane since October.

Reef structures the size of small cars were dislodged or buried in debris, mud and sediment several feet deep, in some instances, Dahlgren said.

Reef diving and snorkeling are an important part of the country’s tourism industry, which accounts for some 50% of its gross domestic product.

Even before the Category 5 storm, the reefs were in jeopardy. In 2016, the Perry Institute, based in Waitsfield, Vermont, found reefs in the Bahamas to be under stress and classified them as impaired, the category just above poor.

Healthy reefs are vital to marine ecosystems in the area, and the storm damage appears to have hit the country’s fisheries as well.

Dahlgren’s team reported a significant decline in fish populations linked to habitat damage. In addition to extremely turbulent waters, Dorian brought a surge of rainwater that changed sea salinity. The storm also caused water temperatures to fluctuate rapidly — both conditions that quite likely shocked the corals, according to researchers.

But the report’s news was not all bad.

“We did see some areas that came out of it looking almost untouched, amazingly,” Dahlgren said.