Port of Miami dredging destroys coral reef

Staghorn coral buried in sediment as a result of Port of Miami dredging operation. Credit: PortMiami/National Georgraphic

A team of researchers including scientists from the University of Miami (UM), USA, have published findings in the Marine Pollution Bulletin journal, estimating that over half a million corals have been killed in a recent dredging operation.

The damage has been attributed to a 16-month dredging operation in the Port of Miami that began in 2013. The study, known as Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes, found that the majority of the coral reefs affected were situated within 500 m of the dredged channel due to sediment burying between 50-90% of nearby reefs.

Andrew Baker, associate professor of marine biology and ecology at the UM Rosentiel School and senior author of the study, commented, “Coral reefs worldwide are facing severe declines from climate change, if we want to conserve these ecosystems for the generations that come after us, it’s essential that we do all we can to conserve the corals we still have left. These climate survivors may hold the key to understanding how some corals can survive global changes. We have to start locally by doing all we can to protect our remaining corals from impacts, like dredging, that we have the ability to control or prevent.”

The contributors to the study analysed data that had previously been collected as part of the dredging’s environmental monitoring programme. The documented coral losses at the time had been attributed to a region-wide outbreak of coral disease. The most recent study however examined losses of coral species that were not susceptible to the disease and found that corals situated closer to the dredge site were more likely to die during the dredge period than those further away.

Lead author and research biologist at Shedd Aquarium Chicago, Ross Cunning, commented, “It was important to differentiate these multiple impacts occurring on the reefs. To understand the direct effects of dredging specifically, we brought together all the available data from satellites, sediment traps, and hundreds of underwater surveys. Together, the multiple, independent datasets clearly show that dredging caused the major damages observed on these reefs.”

The reef track in Florida is the only nearshore reef in the United States, the coral cover has declined by an estimated 70% since the 1970s. Staghorn corals, currently designated as a threatened species un the Endangered Species Act, have declined approximately by 98%.