Exotic corals choke reefs in Venezuela, threatening the Caribbean 

A shadow snakes across the turquoise waters of a beach in Venezuela, a sign of the explosive spread of an Indo-Pacific soft coral off the Caribbean coast that experts consider one of the world’s deadliest marine invasions.

“This is an ecological disaster,” marine biologist Juan Pedro Ruiz-Allais, director of Proyecto Unomia, who has been studying the phenomenon for over a decade, told AFP.

Seen up close, the colonies of these ocher and pink corals perform a surreal dance whose rhythm is determined by the direction of the currents.

While they pose no danger to humans, they harm the environment.

It is believed that the invader, which clings to living creatures, rocks, or the seabed, destroying ecosystems, was illegally introduced for commercial purposes into Mochima National Park, a paradise archipelago covering more than 94,000 hectares between the states of Anzoátegui and Sucre (northeast).

Because of their attractiveness, soft corals are used for ornamental purposes: a polyp that does well in aquariums can cost between US$ 80 and US$120.

When Ruiz-Allais discovered it in 2007, it was “an unknown species in the Caribbean and even the Atlantic,” so “no one knew what it was.”

With the help of Tel Aviv University in Israel, the first scientific report was published in 2014.

It was first classified as a soft coral of the genus Xenia (family Xeniidae), and in 2021 the final identification was made: Unomia stolonifera.

According to “conservative” estimates, this unwanted inhabitant has colonized the area of 300 soccer stadiums on the coast of the state of Anzoátegui (North-Central).

According to recent findings, it is located about 450 kilometers from Mochima, in Valle Seco, a beach near the town of Choroní in the state of Aragua.

The exotic coral, transported by fishing nets, anchors, or ship ballast, reaches Aragua and other regions.

“It is a great colonizer; it suffocates the reefs and makes them disappear,” Gustavo Carrasquel, director of the NGO Azul Ambientalistas, told “AFP” during a visit to Valle Seco.

UNPRECEDENTED CASE

It is an “unprecedented case in the world” because although there are invasive species everywhere on the planet, “an invasion has never gone this far,” said Mariano Oñoro, coordinator of the Unomia project.

In 2018, monitoring of Mochima on the Anzoátegui side found that 16 of the 17 islands and islets were colonized.

On the Sucre side, the scenario is not much different.

There are also reports of Unomia stolonifera in the Cuare Reserve in the state of Falcón (northwest), very close to the islands of Aruba and Curaçao.

The threat extends beyond Venezuela’s borders: exotic soft corals have been detected in Colombian and Brazilian waters.

In Brazil, for example, a 2018 invasion of a soft coral had attached itself to an oil platform, but it was brought under control.

However, there is no record of an invasion as massive as the one detected in Venezuelan waters, Oñoro notes.

A GOVERNMENTAL AFFAIR

The Unomia Project, a privately funded scientific research initiative, has proposed mechanisms to contain the invasion, including a machine developed by a team of engineers and still awaiting approval from the Venezuelan government to be tested.

Fishermen and tour operators concerned about the spread of Unomia stolonifera have resorted to manual removal, but this spreads fragments and creates new colonies.

The extent is so great that complete eradication is impossible.

“We can restore some areas and control them,” Oñoro said. Ruiz-Allais warns that fish populations are declining drastically in eastern Venezuela because of reef death.

“When the reef dies, when it is covered by Unomia stolonifera, the food chain is disrupted,” he explains.

“It’s a social, economic, and food security issue because fishermen’s livelihoods are threatened. It’s a state issue,” Ruiz-Allais notes.

“And it is a problem that will affect the rest of the Caribbean.”