A new disease that kills more than 90% of some coral species has made its first inroads into the rainbow-hued seascapes that cover the Gulf of Mexico’s largest and most valuable coral sanctuary.
Scientists working at the Flower Garden Banks National Marine Sanctuary off the coasts of Louisiana and Texas this month have discovered corals with the tell-tale white lesions linked to hard coral tissue loss disease.
Michelle Johnston, an ecologist at the sanctuary, struggled to spread the word.
“Literally at 3:30 a.m. I’m holding my 3-year-old and I’m texting, ‘I have bad news,'” Johnston said. Though the disease hasn’t been confirmed, Johnston said all the coral experts she’s consulted are “90% confident” that the New Orleans-sized sanctuary is now infected.
About 100 miles off the Louisiana-Texas line, Flower Garden Banks encompasses the northernmost coral reefs of the continental United States and is one of the few places in the Gulf closed to commercial fishing and oil and gas exploration.
Its numerous but fragile corals, growing in myriad shapes and sizes, are a haven for a variety of marine life including manta rays, dolphins, endangered sea turtles and a variety of fish, from the brightly colored found only beneath corals to commercially important species such as grouper and snapper.
The incidence of the disease is reaching a peak for Flower Garden Banks, which has nearly tripled in size over the past year, growing from 56 to 160 square miles. This year marks 30 years since the Shrine was founded in 1992.
While the infected areas of Flower Garden Banks were limited to small patches this week, hundreds of coral colonies have begun to lose color and show early signs of tissue breakdown.
The disease, first discovered in Florida in 2014, has already brought North America’s only barrier reef, which stretches 350 miles across South Florida, to the brink of ecological collapse. The waterborne pathogen quickly spread across the Caribbean Sea and by 2018 had reached the Mesoamerican reef along the coasts of Mexico and Belize, where it managed to ravage over 280 miles in just a few months.
A recent study by Mexican scientists found “unprecedented” mortality rates of up to 94% in 21 species of coral.
“This emerging disease will likely become the deadliest disorder ever recorded in the Caribbean,” biologist Lorenzo Alvarez-Filip wrote in the study, published in the journal Communications Biology.
Not much is known about the disease. Scientists are still debating whether it’s viral, bacterial, or a potent mix of both. Climate change is likely to be an important ally. Warming ocean waters are weakening coral defenses while increasing relatively docile marine diseases. According to Alvarez-Filip, the situation is made worse by pollution, fishing and other human activities, which tend to go hand in hand with sicker corals.
There was some hope that the disease would stay away from Flower Garden Banks.
“I think we were in a bit of denial about the disease and didn’t expect to see this because Sanctuary is isolated,” Johnston said.
Sanctuary divers first found brain and star corals with symptoms of hard coral disease during a routine research cruise that ended Sept. 2. No coral disease was observed during a similar mission in the same area just a week earlier, suggesting the disease was likely a recent onset.
Last week, Johnston presented her findings during a meeting of protected area managers and scientists. A biologist burst into tears.
“I don’t want anyone to give in to despair,” Johnston said at the meeting. “Other places didn’t have a plan and lost time. That is not the case here.”
The sanctuary drew up a plan last year to respond to the disease.
With guidance and training from Florida Atlantic University’s Harbor Branch Oceanographic Institute, sanctuary staff are essentially undertaking medical relief efforts for the corals. The work is tedious, with divers hand-treating individual corals with antibiotics. It’s also expensive, with each offshore trip costing around $900.
The sanctuary cannot simply fall back on federal emergency funds, which are usually earmarked for oil spills or other man-made disasters.
“There’s no one to blame, so we can’t get that kind of emergency response,” Johnston said.
The rescue center can hire volunteer divers to help with treatments.
While Johnston is optimistic about containing the spread of the disease before it gains a foothold in the sanctuary, effective treatments for wildlife diseases are rare, NOAA scientists say. Chronic wasting disease in deer, white nose syndrome in bats and avian influenza are some examples of outbreaks that have spread largely unchecked through wild populations despite extensive efforts to control them.
As an extra precaution, small colonies of highly sensitive coral species are being collected and sent to Moody Gardens Aquarium in Galveston, Texas, which acts as an ark of sorts for the region’s endangered corals. Kept in aquariums and cared for daily, the corals and their offspring could one day be used to repopulate areas depleted by the disease.
The federal government has approved new protections for 500 square miles of deep-sea coral habitat in the Gulf of Mexico.
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