Cleaning scuba equipment between each dive could help slow down the rapid spread of Coral Disease, white blotch-like lesions, that attack and eventually kill coral colonies, local agencies say.
The Florida Reef Tract, the world’s third largest barrier reef and the only in the continental U.S., is suffering from a large-scale stony coral tissue loss, or SCTL, outbreak, which is still spreading south to the Lower Keys.
The disease is thought to be caused by bacteria transmitted to other corals through direct contact and water circulation. The Florida Keys National Marine Sanctuary, Florida Fish and Wildlife Conservation Commission and other agencies have mounted a campaign to combat the disease and protect corals asking divers and snorkelers to decontaminate their gear to reduce the likelihood of transferring SCTL.
Boulder brain coral, pillar coral, which is endangered, and grooved brain coral are among the most susceptible species. SCTL disease doesn’t discriminate and can devour elkhorn and staghorn, also endangered corals, just the same.
Coral mortality ranges from one week for smaller colonies to one to two months for larger colonies.
SCTL first appeared off Virginia Key in 2014 and has since trekked roughly 140 miles south, almost to Looe Key. Sanctuary scientists report that the disease has slowed its coral carnage from about 6 miles a month to about 1.5 miles a month.
“It’s not moving at the same pace it was, but it is still active,” sanctuary Superintendent Sarah Fangman said of the disease’s progression in the Keys. “It’s not spreading right now, but whether it will not be a week or month from now, we can’t say. It’s confounding. It’s unpredictable.”
While coral disease outbreaks are not uncommon, this event is unique due to its large geographic range, extended duration, rapid progression, high rates of mortality and the number of species affected, according to Living Oceans Foundation chief scientist and coral reef ecologist Andy Bruckner.
“Researchers are working to identify potential pathogens and relationships with environmental factors, strategies to treat diseased colonies and identify genotypes of corals that are resistant to the disease,” he said.
Although Bruckner hasn’t seen concrete evidence of this disease being transmitted by people, he thinks dive gear could play a role.
“This is just a precaution. We have to take whatever steps that we possibly can to help prevent this,” he said. “We know it’s spread through water circulation. What we are most concerned with is, that if you’re in a body of water that has a lot of diseases and you go to another area, that pathogen will be on your dive gear and spread.”
Bruckner’s biggest fear is divers spreading the disease long-distance.
He laid out a hypothetical scenario of someone diving off Key Largo, where SCTL has been identified and then boarding a boat to dive around the Dry Tortugas and spreading the disease to that area.
A disease response group, called the “Reef Rescue Team,” is looking to collect samples of different corals on patch reefs in the Lower Keys unscathed by the disease.
There are multiple agencies partnering to fight the outbreak, including agencies throughout the Caribbean.
“Something that looks similar to stony coral tissue loss is now showing in Mexico, and we’re coming together to respond as protocol,” Bruckner said.
Specific decontamination guidelines NOAA recommends:
• Remove debris and sediment following each dive and soak equipment in easily found solutions. For non-sensitive equipment like weights, belts, and tools, soak equipment for 10 minutes in a 10 percent bleach solution, or 1 quart of bleach per 2 gallons of water. Rinse with fresh water and air dry.
• Soak wetsuits, buoyancy compensation devices, mask, and fins after each dive for 10 minutes in either four tablets of RelyOn, 1.3 ounces of Virkon per 2 gallons of water, a quart of Lysol per gallon of water or an equal concentration of another quaternary ammonium disinfectant. Soak in fresh water for 10 minutes then air dry.
• For BCD internal bladders, pour approximately a half liter of disinfecting solution into the mouthpiece of the exhaust hose while depressing the exhaust button, inflate BC and gently rotate in all directions. Allow to sit for 10 minutes. Flush twice with fresh water.
• Soak regulators, computers, gauges, underwater cameras, and other sensitive equipment for 20 minutes in a solution of warm water and antibacterial dish soap or OdoBan at 5 ounces per gallon. Rinse in fresh water and air dry. Additionally or alternatively, thoroughly wipe with isopropyl alcohol.
• Properly dispose of disinfectant solutions and rinse water in a sink, tub or shower. Never pour tainted water into the ocean or a storm drain.
For more information on stony coral tissue loss or NOAA’s decontamination guidelines, visit floridakeys.noaa.gov/coral-disease.
Staff writer Timothy O’Hara contributed to this article.