Silent Killer: What Causes This Stony Coral Tissue Loss Disease That Has Inflicted More Than 20 Species?

A so-called "silent coral killer" is spreading across the Caribbean waters, and according to recent study findings, it has inflicted approximately 22 species.

National Geographic reported that researchers have been racing to prevent stony coral tissue loss disease, which has killed some of the oldest and largest corals of the region.

Infected colonies have developed white patches that enlarge little by little, draining the animals' color and life.

In the most vulnerable species like the brain, pillar, and star corals, infected colonies typically die within months or even weeks from infection. According to Florida-based coral disease specialist William Precht, it is the worst thing he has ever seen.

ALSO READ: Why Coral Reefs Turn White? Science Explains

(Photo: G.Mannaerts on Wikimedia Commons)
Stony coral tissue loss disease

Stony Coral Tissue Loss Disease

Abbreviated as SCTLD, stony coral tissue loss disease was first discovered in corals off Miami in the fall of 2014, the National Park Service reported. This disease, possibly spread by a microbe or virus, or a combination of both, has already expanded throughout the coast of Florida and a big part of the northern Caribbean.

It currently exists in at least 20 nations, from Mexico to Honduras, to St. Lucia. Then, in May this year, corals turned infected with the disease in the Dry Tortugas National Park of Florida, a known hot spot for coral diversity.

As earlier mentioned, researchers, which include Precht, are now racing to find out what causes the disease, how it's spreading, and how it can get treated.

SCTLD may have propagated slowly through water currents, but the new study published in Frontiers Marine Science suggests it may also be transmitted by commercial shipping vessels at main ports like the one in the Bahamas.

Essentially, Caribbean corals, which are forming their reef ecosystems' basis, are already threatened by warming waters because of climate change, nutrient runoff, and pollution, which makes solving the mystery much more difficult.

How SCTLD is Spread and Can be Prevented

The occurrence of SCTLD elsewhere has frequently been likewise abrupt, not to mention devastating. In 2019, the disease had not yet appeared in the Bahamas, partly because the prevailing ocean current is running northward up the Florida coast.

That same year, in October, Craig Dahlgren, a marine ecologist, and colleagues investigated roughly 60 miles of reef and discovered "no sick coral."

However, a month after, the team got the team was receiving reports that corals close to Freeport had an identified infection, which later proved to be the said 'silent killer' disease.

Then, during another comprehensive survey in May last year, Dahlgren, along with the Perry Institute of

Marine Science examined more than 60 miles of reef again and discovered infected corals in each site, specifically brain and pillar corals. Within a few months, the vast majority of the infected colonies were dead.

Dahlgren explained that to prevent the spread of the disease between islands, ships need to be more cautious about the manner and time they are exchanging ballast water and avoid releasing it close to ports and coral reefs, which are described in a separate National Geographic report.

Related report about the stony coral tissue loss disease is shown on Perry Institute for Marine Science's YouTube video below: