Deadly coral disease found over 4-mile area

DoE launches reporting app, enlists public’s help in fight

Department of Environment researchers say they are growing increasingly worried as the deadly Stony Coral Tissue Loss Disease, first spotted at Penny’s Arch in the Rum Point channel, appears to have spread over a four-mile area.

The researchers are working to contain the disease at its epicentre in the North Sound and keep it away from the prized Seven Mile Beach reef.

“We sort of isolated it mainly to the north side of Grand Cayman and the Rum Point area and [have] focussed our efforts on that and doing mitigating factors to contain the disease over time,” Croy McCoy, DoE senior research officer, told the Cayman Compass on Wednesday.

He said data has shown that the disease, which was first discovered locally in late June by a diver, seems to be moving approximately a nautical mile a month along the reef track, and so far has infected more than 20 species of stony coral.

“[It] is highly contagious and the virulence factor for the disease is very high,” McCoy said. “They have been trying to figure it out since 2014. It first emerged in Florida in the port of Miami and they haven’t yet [determined the cause].”

The disease, which is believed to be caused by a pathogen, is known to attack several types of coral, including primary reef-building species, like pillar coral, elliptical star coral, maze coral, brain coral and smooth flower coral.

“It can be considered, I guess, COVID-19 of the reef,” McCoy said, since the DoE has not been able to “identify the pathogen or the virus responsible for it”.
Cayman, he said, has a unique opportunity to research the disease, unlike other Caribbean countries whose reefs have been devastated by the disease.

Tracking the disease

Visiting researcher Tammi Warrender has been part of the team leading the charge to fight the spread of the disease here.

She said a massive effort has been undertaken to document the reefs on all three islands.

“We don’t know how it travels and whether it’s completely water borne or whether it was brought here by a boat. We’re not completely sure of that yet. So, there’s ongoing research into that area and that means that it can turn up at any time. We surveyed around 60% of Grand Cayman, we’ve done 85% of Cayman Brac, and in Little [Cayman] just under 50% of the island has been surveyed for this disease,” she said.

Department of Environment visiting research officer Tammi Warrender and senior research officer Croy McCoy are leading the charge to slow the spread of the disease along Cayman’s reefs. – Photo: Reshma Ragoonath

Given the virulence of the disease and the wide area to cover, the DoE has launched a platform which DoE Deputy Director Tim Austin said he hopes the public will use the to report sightings.

“We’re very dependent on the public taking part in the surveys to let us know if they see any signs of this disease. We… need to be able to act fast when we do see it. So we’ve developed an app in-house… we’ve called it the Cayman Islands Coral Disease and Bleaching app,” he said.

He said the platform poses a series of questions and has the ability to use the GPS on smartphones, as well as to upload pictures and describe what has been seen on the reefs.
“It’s a convenient way for us to collect [informaton], as well. So the [platform] is very simple to use and we encourage people to have a look at that and … keep their eyes open on the reef when they’re snorkelling or diving, and make any reports they can,” he said.

Austin stressed that it was very important that the DoE finds out as soon as possible what sites are affected, so it can act fast.

Daily checks, removal part of strategy

McCoy said they have determined that there are four highly susceptible species that the disease infects ahead of its spread throughout the reef.

“Those species sort of light little fires… and then… infects all the others,” he said, adding, “We know there are four that are highly susceptible and they sort of lead the way with this whole thing, coming along the reef, [infecting] the rest of corals and [killing] them off,” he said.

He said the disease is spreading east and west of the epicentre, which is located north of the Rum Point area.

Warrender said stopping the spread quickly is vital.

“We are worried about it progressing on all of our reefs, but we also have the Marine Park on the west coast that is very important to the Cayman Islands for tourism and for the economy. So we started removing corals from the perimeter of the western extent of the disease, and we’ve been working back towards the heavily diseased area, which is just outside of the Rum Point channel, and we’ve removed 200 colonies in four days,” she said.

The DoE is reminding the public that removing coral from the reef is illegal, and only authorised DoE personnel are allowed to treat or excise the diseased coral.

Warrender explained that the DoE is exploring its options on treating the impacted reefs, including utilising antibiotics and probiotics like those used in the Florida infestation.

She said the DoE’s Sister Islands field officers and volunteers, including those from Reef Divers Cayman and Brac Scuba Shack, have been helping map the corals in the Brac and Little Cayman through boat tows.

“We hang off the back of the boat and if someone sees some bright white coral on the reef, then we’ll stop and we’ll go and snorkel down and take a look at and see… whether it is Stony Coral Tissue Loss Disease… thankfully we haven’t found any on the Sister Islands, and we haven’t found [it] on any other parts of the reef, apart from outside of the Rum Point Channel, so we believe it’s isolated,” Warrender said.

She said she is fairly confident that the current epicentre is a small-enough space that the DoE can still do something about it.

“Most researchers in the Caribbean have unfortunately not had the opportunity that we have had here because by the time they can act, they already have the reef around their whole island [infected]. We’re in a very good position for dealing with it in comparison to other people in the Caribbean,” she said.

Austin added that the DoE is working with the Joint Nature Conservation Council in the UK to seek funding to help in the effort to save Cayman’s reefs.


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