A new study reveals for the first time that dredging activity near coral reefs can increase the frequency of diseases affecting corals.

“Corals require both light and food to survive,” lead author Joe Pollock, PhD candidate from the ARC Centre of Excellence for Coral Reef Studies explained in a news release. “And unfortunately, dredging impacts corals on two fronts: increased turbidity means less light for photosynthesis, while increased levels of sediment falling onto the coral can interfere with their ability to feed.”

Already low on energy from a lack of food and light, the corals have to expend even more energy cleaning the sediment from their surface. This can lead to chronic stress, which leaves corals more vulnerable to disease.

This is the first-ever study to examine the link between dredging and coral disease. It was conducted near Barrow Island, off the West Australian coast, close to where an 18-month, 7-million cubic meter dredging project took place.

“At dredging sites, we found more than twice as much coral disease than at our control sites,” Pollock said.

The most common diseases they encountered were the ‘white syndromes’, where corals lose their tissue and are left as white skeletons.

As shipping increases and coastal communities continue to expand, there is a growing demand for larger harbors, making the dredging process a worldwide concern.

“A solid understanding of the impacts of dredging, sediment and turbidity on coral health will be indispensable in the development of well-informed management and monitoring strategies for vulnerable coral reef ecosystems,” Pollock concluded.

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