A decade after transplantation, red coral colonies (Corallium rubrum) in the Medes Islands Marine Reserve have not only survived but are thriving, playing a crucial role in restoring the reef ecosystem. These transplanted corals closely resemble natural colonies and have significantly contributed to the recovery of coral reef functions, despite the species’ notoriously slow growth.
A Second Chance for Seized Corals
These colonies were originally confiscated from illegal fishing activities and given a second chance at survival through a restoration initiative led by scientists from the University of Barcelona (UB) and the Institute of Marine Sciences (ICM-CSIC). Their efforts focused on replanting the seized corals to mitigate the effects of poaching.
The latest findings, published in Science Advances, highlight the long-term success of these restoration efforts. The study was led by experts Cristina Linares and Yanis Zentner from UB’s Faculty of Biology and Biodiversity Research Institute (IRBio), along with Joaquim Garrabou from ICM-CSIC.
Long-Term Coral Restoration Success
The research provides strong evidence that transplanting seized corals leads to long-term survival and ecosystem recovery. Previous studies had shown promising results after four years, but this latest assessment—conducted after ten years—demonstrates the lasting impact of active marine restoration efforts.
In the context of the UN Decade on Ecosystem Restoration (2021–2030) and the European Union’s Nature Restoration Act, this study stands out as one of the few research projects evaluating long-term coral restoration success in the marine environment.
How Transplanted Red Coral Helps Rebuild Marine Habitats
Red coral poaching remains a serious threat, even in protected marine areas. Due to its slow growth rate, natural populations struggle to recover from overexploitation. The restoration efforts took place in the MontgrÃ, Medes Islands, and Baix Ter Natural Park, at a depth of approximately 18 meters—an area with no recent poaching activity and, for now, minimal climate change impact.
The study confirms that replanting seized corals has led to both high survival rates and the rapid recovery of associated coral communities.
According to Professor Cristina Linares (UB), the transplanted coral colonies have transformed their environment over the past decade.
“The restored community has fully developed in just ten years, closely resembling natural red coral habitats. This highlights the crucial role of habitat-forming species like red coral in marine conservation and restoration.”
Climate Change Threats to Transplanted Corals
Despite the success of coral transplantation, climate change poses an ongoing threat. Rising temperatures and marine heatwaves have caused mass mortality in red coral populations and over 50 other Mediterranean species.
Illegal coral harvesting for jewelry further endangers these slow-growing colonies, which thrive in deep, hard-to-reach habitats.
According to Yanis Zentner (UB-IRBio), first author of the study:
“If climate change impact remains minimal, we expect the coral community to reach full maturity much faster than anticipated. However, we still need long-term data to confirm whether these reefs can fully restore their original functionality.”
To minimize climate change effects, researchers suggest conducting future transplantation efforts at depths of 30 meters or more, where ocean warming has a less severe impact on coral health.
Why Long-Term Monitoring Matters in Marine Restoration
Traditional restoration projects often focus only on short-term survival, but this approach is insufficient for long-lived species like coral, which can live 50 to 100 years.
“Many marine species require decades to fully recover, so short-term studies fail to capture ecosystem-wide changes in biodiversity, structure, and function,” explain Linares and Zentner.
The research team advocates for long-term monitoring using community-scale analyses to assess ecosystem-wide changes.
Scaling Up Marine Restoration Efforts
Although coral restoration is well-studied in tropical reefs, long-term success remains poorly evaluated, especially given increasing climate change threats.
In the Mediterranean, researchers have previously restored gorgonians and corals rescued from fishing nets, but large-scale marine restoration is still in its early stages.
“For restoration to be effective, we must first eliminate the human-caused stressors damaging marine ecosystems,” the researchers emphasize.
They also stress the need to scale up restoration projects, as current efforts—often small and localized—fail to achieve ecosystem-wide recovery.
Conclusion
The Medes Islands red coral transplantation project provides a rare example of long-term restoration success in marine conservation. These findings reinforce the importance of protecting and restoring red coral habitats to combat poaching, promote biodiversity, and enhance ecosystem resilience.
As climate change and human activities continue to threaten marine ecosystems, scaling up restoration efforts and adopting long-term monitoring strategies will be crucial for ensuring the survival of vulnerable species like red coral.