Hundreds of thousands of corals destroyed because of port of Miami dredging

In what could be considered a very serious blow to rich marine life, a new study has pointed out that nearly half a million corals have been destroyed because of port of Miami dredging.

The study by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science point out there has been significant damage to Miami’s coral reefs from the 16-month dredging operation at the Port of Miami that began in 2013. The study found that sediment buried between half to 90 percent of nearby reefs, resulting in widespread coral death.

The results, published in the journal Marine Pollution Bulletin, estimate that over half a million corals were killed within 550 yards (500 meters) of the dredged channel, and that dredging impacts may have spread across more than 15 miles (25 kilometers) of Florida’s reef tract.

The researchers reanalyzed data originally collected by consultants as part of the dredge’s environmental monitoring program. This program had attributed most of the documented coral losses in the area to a region-wide outbreak of coral disease that occurred at the same time. The new study controlled for these impacts by looking at losses of coral species that were not susceptible to the disease and by testing whether corals closer to the dredge site were more likely to die during the dredge period than those further away. The new analysis revealed that most of the documented coral losses near the Port of Miami were in fact the result of dredging.

Florida’s reef tract is the only nearshore reef in the continental United States, and coral cover has declined by at least 70 percent since the 1970’s. Staghorn corals, which were once common in shallow water, have declined an estimated 98 percent and are now threatened species under the Endangered Species Act. The affected areas adjacent to the dredge site are of high conservation value and have been designated as “critical habitat” for the recovery of these threatened staghorn corals. Nationwide, coral reefs provide over $1.8 billion in flood risk reduction annually.

The researchers also studied whether sediment plumes – milky clouds of suspended dredging sediment visible from space – could predict impacts observed on the reefs below. The authors found that plumes detected using satellites had a remarkably high correlation with impacts documented on the seafloor. This is the first study to show that satellite data can be reliably used to predict dredging impacts on corals and their habitats.