TOAMASINA, Madagascar — The landscape was primed for adventure during a mid-April visit to L’île aux Prunes, an idyllic islet selected by the NGO Tany Ifandovana for transplanting rescued corals. With its nearly virgin tropical forest and maze of trails, the islet, known locally as Nosy Alanana, has a well-earned reputation as a former hideout where pirates once supposedly hid their loot.

The reef where the corals originated was due to be filled in for the expansion of the port of Toamasina, a city on Madagascar’s east coast. The young NGO is trying its best, with few resources and little support from the port itself, to compensate for at least some of the ecological destruction.

“As an environmentalist, it hurt my heart to know that these corals were just going to be filled in,” Jean Maharavo, marine biologist and vice president of Tany Ifandovana, told Mongabay. “Something had to be done.”

The deep-water port of Toamasina is the largest and most important in Madagascar, handling 90% of the country’s international cargo flows. The expansion adds 25 hectares (62 acres) to the port’s initial 70-hectare (173-acre) footprint, with the ultimate goal of tripling the port’s capacity by 2026.

The port is surrounded by a series of coral reefs: Hastie Reef, Bain des Dames Reef, Grand Reef, Petit Reef, and the reef at L’île aux Prunes. To carry out the expansion work, part of the first two reefs will be filled in.

According to the environmental impact report produced by the Japan International Cooperation Agency (JICA), through which Japan is partly financing the Malagasy government’s port expansion work, there are around 15 different species of coral at Hastie Reef. A study by Maharavo, carried out before the infilling, indicates that Bain des Dames Reef is home to 46 species of coral, with coral cover between 60% and 90%. There are near-threatened species among the corals on both reefs, such as Pavona decussata, P. cactus and Acanthastrea brevis.

In an attempt to save these corals and compensate for the impacts of the port expansion, Tany Ifandovana, in partnership with French company Creocean, transplanted a small portion of the reefs to L’île aux Prunes, 17 kilometers (10.5 miles) from Toamasina.

“I think this is the only port in Madagascar where there are so many important reefs, and the fact that the corals were going to be destroyed caught our attention,” Maharavo said.

One transplant, three techniques

Tany Ifandovana’s coral transplant initiative began with an experiment that Maharavo conducted with a student named Sidonie Alexandre who was working on her thesis. It involved seeing if corals from Bain des Dames could be harvested and transplanted around L’île aux Prunes.

They chose the island as a destination both because it’s not impacted by port activities and because it has also suffered heavy coral losses due to uncontrolled fishing along its shore and the use of fishing nets. According to Maharavo, before the transplant, there was only 25% coral cover left on the island’s reef flat, in waters 1-3 meters (3-10 feet) deep at high tide, and 40% on the deeper reefs, at 9-10 m (30-33 ft).

Maharavo and Alexandre experimented with two techniques. The first uses a concrete-based mixture, known as Sikacrete, to glue coral cuttings directly to the reef. The second uses a spider-shaped metal structure to which the cuttings are attached. A third, tested only by Maharavo, involves using metal clips to attach the corals directly to the solid rocks. Each technique was applied accounting for the hydrodynamics of the planting areas.

After seeing the experiment results, Tany Ifandovana applied for and received a grant from Madagascar’s Ministry of Fisheries and the Blue Economy, as part of a World Bank-funded project called Swiofish 2, to expand the transplant project over 0.4 hectares (1acre).

Tany Ifandovana began the transplant work in 2023 with 5,000 coral colonies collected from the port site before the infilling work. After one year, the survival rates are 70%, 60% and 80% respectively for the Sikacrete, the metal clips and the spider structures.

Full vs. partial ecological compensation

The only contribution from the SPAT, the public authority responsible for managing and operating the port of Toamasina, has been to facilitate administrative permits for coral transplants. It didn’t provide any funding for the transplant program. SPAT also didn’t respond to Mongabay’s request for an interview.

“Although our goal is to compensate for the losses related to the port expansion, officials do not like to use the term ‘compensation,’” Maharavo said. He added that he suspects officials are reluctant to get involved in a long-term project that requires a lot of resources.

But even Maharavo said he’s not aiming for complete ecological compensation, which planners call “offsetting,” precisely because of the lack of resources. The corals his team has so far transplanted are far from compensating for the losses resulting from the port expansion: 0.4 hectares planted against 25 hectares expected to be lost, or 1.6%. When this story was originally published in French in October, approximately 10 hectares (25 acres) of corals had been lost, with expansion work set to continue. Tany Ifandovana plans to continue transplanting what it can, if it can obtain more funding.

For an ecological offset to be effective, “it is crucial to be able to reconcile and demonstrate how the new biodiversity is equivalent to that lost, and also that it is indeed new, [in other words] that it adds to the biodiversity that would have existed there in the absence of the project,” Holly Niner, an expert in blue finance and nature-based solutions at the University of Plymouth in the U.K., told Mongabay.

According to Niner, the common strategy for marine biodiversity offsetting follows a four-phase hierarchy. The first phase is to reduce potential impacts of the project as much as possible at the design stage, while the second aims to minimize unavoidable impacts. The third is to remedy impacts by directly replacing the biodiversity in the same place, if possible, and the fourth phase is the actual offsetting: To add new biodiversity equivalent to that lost at a new site.

SPAT didn’t subject the Toamasina port expansion to such requirements. While there are international commitments to protect biodiversity, there’s no measure requiring governments to carry out ecological offsets.

Furthermore, the minimum monitoring period for coral transplants should be at least five years, or even longer, to determine long-term survival, said Nicki Shumway, a marine conservationist at the University of Queensland in Australia, who studies ecological offsets.

“From a scientific perspective, I would say decades at a minimum, but I understand … why this is not always feasible (for example, limited funding cycles),” she told Mongabay in an email. “That’s why most projects get only 2 years of monitoring, if at all.”

Tany Ifandovana doesn’t have funding for monitoring, and only makes occasional checks on the transplanted corals while waiting for other partnerships to gel.

And while there’s no real standard for measuring coral transplant success, a recent study suggests that after two years, a survival rate of less than 50% can be considered poor, 50-60% below average, more than 60% acceptable, and more than 80% excellent.

For example, the study describes the results of a coral transplant program compensating for pipeline development near Hayman Island in Australia’s Great Barrier Reef, which had a survival rate of 77.5% after two years of follow-up. Another particularly successful example was carried out in Broward county, Florida, in the U.S., to compensate for coral loss associated with pipeline, cable and sewer construction. The 1,100 transplanted colonies had a survival rate of between 87% and 99% after two years of follow-up.

“So while global data is limited, there is evidence that coral relocation can be a successful strategy,” Shumway said.

On the other hand, marine ecological offset projects generally face the common problem of data scarcity. It’s harder to perceive results at sea than it is on land, because the data isn’t easily accessible. To collect it, professional divers may be necessary, for example. L’île aux Prunes is difficult to access half the year, as it’s frequently exposed to winds and high waves. All boats passing through the port to get to L’île aux Prunes must also obtain authorization from the port authority, making monitoring difficult.

Ongoing destruction

In addition to the lack of funding hampering its project, Tany Ifandovana faces other challenges that can’t be easily solved. The newly transplanted corals are subject to the same anthropogenic pressure as those that initially grew around the island. With the NGO’s monitoring activities currently limited, the new corals are at risk of being destroyed by fishers.

“At low tide, fishers walk directly on the corals with their big rubber boots,” Maharavo said. “There are no regulations that prevent them from doing so, so they can do what they want.” Evidence of the fishers’ presence is visible on L’île aux Prunes, where thousands of pieces of coral broken from nearby reefs litter the beach. Most are bleached, but some are still alive, a sign that they were recently destroyed.

There’s nothing to prevent resource exploitation on the island. Although there’s a permanent caretaker, he’s responsible only for the lighthouse. And while the island is supposed to be protected by fady — Malagasy sociocultural and spiritual taboos — preventing the degradation of its environment, these are apparently not respected. Maharavo said Tany Ifandovana is planning an advocacy initiative to make the island a protected area, but this could take two to three years.

Other reefs near the port are no less exposed than L’île aux Prunes. They, too, are subject to fishing activities, as well as to global warming, like reefs around the world. In Toamasina, people also use corals instead of pumice stones to construct septic tanks , an unusual activity that’s taking a toll on local reefs. Collectors mainly take coral blocks from Grand Reef.

“I don’t really see the advantage of planting corals only on L’île aux Prunes, if on the other side [at Grand Reef], we continue to damage them, because, in my opinion, the two reefs complement each other,” a local fisher named Rabetodisoa told Mongabay.

Under these conditions, there’s no guarantee of long-term survival for the corals saved by Tany Ifandovana. Rather, the NGO’s objective of ecological compensation for some of the destruction caused by the port expansion will require long-term work.

Maharavo seemed to have given up on hopes of financial support from the port and said he plans to turn to the private sector. As of this story’s original publication in French, Tany Ifandovana was in discussions with Réfrigépêche, a large Malagasy fishing company, to try to secure funding for the continuity of its project.

Banner image: Infill of 10 hectares (25 acres) on Hastie Reef, part of the project to expand the port of Toamasina. Image courtesy of SPAT via Sea-Seek.

This story was first published here in French on Oct. 10, 2024.

Citations :

Alexandre, S., Maharavo, J., Remisy, S., & Rasoanarivo, R. (2019). Etat (t0) du récif du Bain de Dame avant l’extension du port de Toamasina. Revue des Sciences, de Technologies et de l’Environnement, 1. Retrieved from http://madarevues.recherches.gov.mg/?ETAT-T0-DU-RECIF-DU-BAIN-DE-DAME-AVANT-L-EXTENSION-DU-PORT-DE-TOAMASINA

Smith, A. K., Cook, N., Songcuan, A., Brown, R. E., Molinaro, G., Saper, J., & Keane, K. (2024). Effectiveness of coral (Bilbunna) relocation as a mitigation strategy for pipeline construction at Hayman island, Great Barrier Reef. Ecological Management & Restoration, 25(1), 21-31. doi:10.1111/emr.12590

Stephens, N. R. (2007). Stony Coral Transplantation Associated with Coastal and Marine Construction Activities (Master’s thesis). Retrieved from https://nsuworks.nova.edu/occ_stuetd/258/

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