Coral relocation can help alleviate some impacts of dredging but moving an entire ecosystem is “impossible”, according to Cayman’s research centre, the Central Caribbean Marine Institute.
While some corals may be successfully moved to new reefs, Carrie Manfrino, director of CCMI, said transplanting a complex network of caves and tunnels, topped with coral formations rising to 30 feet in places, was not realistic.
She said no-one should be fooled that this was what coral relocation would mean. She said the consultants’ aim was rather to transplant live corals from the impacted zone to create new habitat on artificial structures elsewhere.
“Replacing what is lost is impossible,” she said.
“The restoration activities planned are not aiming to restore the site that is destroyed. The idea is that they will produce other reefs to compensate for the harm they cause.”
Other experts are more upbeat about the prospects of success.
Bill Precht, a scientist who has advised the Department of Environment in Cayman on previous coral-restoration projects, said he believes a project on the scale envisaged for Grand Cayman is a massive undertaking.
But he thinks it can and should be done if the port project proceeds.
Precht echoed CCMI’s warning that coral relocation could never be a “like for like” replacement for what is lost. But he said it was worth trying to rescue what could be salvaged.
Manfrino said CCMI researchers dived the impacted sites in recent weeks and concluded that it was an ecosystem with above-average coral coverage. She said a Swiss-cheese-like limestone formation covered with coral patch reefs is home to Nassau, tiger and yellowfin grouper, as well as parrotfish, chub, turtles and lobster.
“We feel it is important to make the distinction between restoration versus relocating the coral. One does not counteract the other because the corals are not the entire ecosystem,” she said.
“We believe that degrading the ecosystem by removing the coral can have far-reaching impacts, many of which will not be seen immediately.”
Different studies have been cited about the potential success rate of coral relocation.
Government and Verdant Isle have referenced a 2018 project led by Lisa Bostrom-Einarsson, as a part of the National Environmental Science Programme in Australia, which reviewed 329 case studies of coral restoration and outlined an average success rate of more than 60%.
Manfrino points out that this refers only to the survival of corals and doesn’t factor in other impacts, such as overall ecosystem degradation. She said most studies cited only looked at survival rates after 18-30 months. In many cases, she said, it would take much longer for the real success or failure rate to be seen.
Mixed results from other projects
Precht, who has worked for NOAA and authored the ‘Coral Reef Restoration Handbook’, said there were examples where coral relocation had been successful and others where it had failed.
He cited Falmouth, Jamaica, as one instance where it had been “horribly unsuccessful” but said a separate project in Roatan, Honduras, was widely regarded as a success.
“My view is that if this project is going to happen and the reefs are going to be impacted, then those corals need to be moved, but they need to be moved by the right team in the right way,” he said.
Precht noted that early results from a previous restoration project in Grand Cayman had been positive. But he cautioned that the scale of the undertaking in this instance was “orders of magnitude” greater and would need to involve an expert team, including divers, geologists and construction experts, among others.
“It is going to take an incredibly large team of people, a lot of boats, a lot of scuba tanks,” he said.
He estimates that to successfully relocate corals from the harbour on the scale outlined, it would take a team of 30-50 people working seven days a week around nine months to complete.
He said the project would inevitably involve some “diminution” of the habitat but said a new functional coral reef habitat could be created.
“If the (port) project is going to happen you have to give it a try,” he said. “But it needs to be done properly.”
Precht cautioned that even if it is successful in minimising coral loss, the relocation won’t fully mitigate the loss of coral reef habitat in the harbour.
The coral-relocation project would be carried out by Verdant Isle through their partner Polaris Applied Sciences. As with other aspects of the mitigation plan, it would be monitored by the Environmental Assessment Board.
CCMI has raised questions over whether the proponents of the project should be so closely involved with the coral-restoration efforts and indicated a willingness to help with an ecosystem-wide restoration strategy, should the public vote to go ahead with the project.