Rewilding Mustique’s Reefs

IT’S NO SECRET THAT CARIBBEAN REEFS ARE IN CRISIS. Muchas especies de coral duro se enfrentan a un destino incierto, y algunos pronosticadores científicos apuntan a la extinción de algunas especies en un futuro cercano.

La cobertura de coral ha disminuido drásticamente desde la década de 1960, y las pérdidas más significativas se encuentran entre los dos tipos dominantes de ramificaciones de coral: el coral cuerno de alce (Acropora palmata) y el coral cuerno de ciervo (Acropora cervicornis). These two critically important species have been reduced by 80 percent — up to 97 percent in some areas — of previous healthy baseline populations.

Los motivos de este impresionante descenso incluyen polución de cuencas (escapes de productos agrícolas, químicos y aguas residuales), sobrepesca, aumento de la temperatura del mar a nivel mundial, enfermedades del coral y la mortalidad masiva de los erizos de mar de espinas largas en 1983 y 1984. Los erizos de mar de espinas largas son una especie herbívora clave que ayuda a evitar que las algas de crecimiento rápido asfixien a las colonias de coral.

Mustique is a small, private island in the Caribbean’s Lesser Antilles and one of the 32 islands that make up St. Vincent and the Grenadines. Mustique is managed by The Mustique Company at the behest of the island’s approximately 100 foreign homeowners. In 2014 Bryan Adams, chairman of The Mustique Company’s Environmental Committee, was troubled by the degraded condition of the island’s corals. The reefs were scrubby rocks with some gorgonian soft corals and haggard-looking sea fans, extensive clumps of macroalgae, various species of sponges, and dispersed heads of brain and star corals. Fish were sparse and flighty.

Tidal surge and wave action continually massage the island, providing oxygenation and a steady supply of food — a secret sauce that makes the elkhorn corals thrive.

Mustique’s reefs were not always that way; 50 years ago they were beloved by snorkelers and divers. As the island developed, however, wastewater, fertilizer, and chemicals found their way into the sea, which may have lessened the corals’ resistance to disease. In 1986 Hurricane Danielle exacerbated this pollution, which caused wholesale devastation of the reefs in Plantation Bay off the island’s southwestern shore. The beautiful reefs of Mustique were but a fond memory.

En los años siguientes, el Comité Ambiental y los residentes prestaron más atención a los impactos de los humanos en la isla e implementaron una variedad de medidas ambientales, incluso eliminar los vertidos de agua dulce y aguas residuales hacia el océano a través de la construcción de muros de contención, la eliminación gradual de sustancias químicas tóxicas, el aumento del reciclaje, la eliminación gradual de bolsas plásticas, la minimización de plásticos de un solo uso y el aumento de la dependencia de la energía solar. La isla tiene una zona de protección total de 914 metros (1.000 yardas) donde se prohíbe la pesca que está patrullada por el personal de seguridad de la isla.

Adams learned about the nascent coral restoration programs Ken Nedimyer, technical director for Reef Renewal USA, was implementing in the Florida Keys and wanted an assessment of Mustique’s reefs. Nedimyer and his team found them degraded but not entirely hopeless and proposed to rewild the reefs through coral plantings. Returning to the island in 2015, they set up a coral nursery seeded with fragments of locally harvested elkhorn, staghorn, and blade fire coral (Millipora complanata). They suspended these fragments in the water column of a shallow bay, hanging them from cross tees of fiberglass “trees,” buoyed by floatation and anchored to the bottom in 25 feet of water.

The fragments thrived and were soon harvested and broken down into 1 inch by 1 inch “frags” and attached to bare rock with marine epoxy. The coral began to grow and establish limestone skeletons, creating their own stable anchors to the rock substrate.

Los fragmentos diminutos de corales cuerno de alce y de fuego aplanados comenzaron a crecer y desarrollarse en las aguas superficiales. En un año quedó claro que los corales estaban acoplándose a esta extensión de arrecife de roca recientemente colonizada. El coral cuerno de alce puede crecer de 5 a 13 pulgadas por año, y sus colonias pueden vivir por décadas y, en último término, alcanzar una altura de 1,8 metros (6 pies) y un ancho de 3,6 metros (12 pies) en condiciones ideales.

Tidal surge and wave action continually massage the island, providing oxygenation and a steady supply of food — a secret sauce that makes the elkhorn corals thrive. The staghorn corals, however, have not fared as well, growing for a time but then get smothered in mats of macroalgae that also thrive in the shallow, sunlit waters.

Han pasado siete años desde el cultivo inicial de coral, y los corales cuerno de alce han crecido y se han expandido hasta formar impresionantes matorrales. Las ramas de coral albergan a una variedad de especies de peces, lo que incluye candiles, peces roncadores, peces puercoespín, peces trompeta, peces Damisela, peces ángel, peces mariposa y anguilas, así como también habitantes invertebrados como erizos de mar, langostas y pulpos. El arrecife se ha vuelto un lugar concurrido, poblado y vibrante.

Since 2015 more than 7,500 coral fragments have been planted along Mustique’s coast. The biomass of fish is increasing, and the quality of sea life encounters is improving. But reef rewilding (restoration) does not equate to a return to nature in its original state. It involves making smart decisions, prioritizing the greater good, and achieving what is possible. Planting two or three types of coral in a locale that was once home to dozens of species may seem meager, but it is a start. Nedimyer likens it to planting a few species of trees in a reforestation project.

“You may only plant a couple species of trees, but as they grow, they attract wildlife, which facilitates the introduction of other species of plants and trees,” Nedimyer said. “Over time the replanted forest starts to look and function like a real forest.”

Recreating nature, or attempting to, is not without physical and financial costs, which the volunteers and community members bear. But what is the cost of not lending a hand to nature — especially when our predecessors caused the damage, inadvertently or not?

What is the value of a dead reef compared with the value of a living marine ecosystem?

La naturaleza tiene un valor que va más allá de los beneficios financieros imprevistos a corto plazo, y debemos pagar el precio que sea sin vacilar para poder restaurar la naturaleza otra vez.

While it’s still a work in progress, the restoration and rehabilitation of this formerly austere rock reef into a coral garden brings a great sense of achievement to the island community and its visitors and provides an example of a positive way forward for reef stewardship. AD

© Alert Diver — Q4 2022