Concrete Substrates for Accelerated Coral Restoration in the Philippines

Acanthasia: Supporting Coral Regeneration and Marine Habitat Recovery

Concrete Substrates for Accelerated Coral Restoration in the Philippines

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    Concrete Substrates for Accelerated Coral Restoration

    Marine biodiversity and fish stocks are vital for local communities who rely on fishing for food and economic development

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    Concrete Substrates for Accelerated Coral Restoration

    The “concrete starfish” prototype was first introduced in early-2000 at Duka Bay in the Southern Philippines. Project Update 2010.

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    Concrete Substrates for Accelerated Coral Restoration

    Concrete is the ideal material for the coral substrate. - Project update 2010

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    Concrete Substrates for Accelerated Coral Restoration

    Young corals can soon be harvested and successfully transplanted to other areas. Project Update 2010.

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    The Holcim Foundation pavilion at the Nobel Laureates exhibition and conference 2009 in Lindau, Germany features Acanthasia, a project to accelerate the cultivation of corals on starfish shaped concrete structures.

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    Cluster of pavilions on the economic, environmental and social importance of water at the exhibition in honor of Nobel laureates conference 2009 in Lindau, Germany.

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    Holcim Foundation Awards 2005 for Asia Pacific

    Concrete Substrates for Accelerated Coral Restoration (l-r): Rolf Soiron, Chairman of the Advisory Board of the Holcim Foundation, Chairman of Holcim Ltd, Switzerland; Tom Clough, Member of the Executive Committee, Holcim Ltd, Switzerland; Jaime Victor B. Ledda, Philippine Consul in China; and team members Lemuel Ranalan Alfeche; Ronald Roland Cesar Rodriguez; and Oscar Halibas Cinco.

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    Concrete Substrates for Accelerated Coral Restoration

    Its shape, with the eight elongated legs is reminiscent of a starfish.

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    Concrete Substrates for Accelerated Coral Restoration

    Marine biodiversity and fish stocks are vital for local communities who rely on fishing for food and economic development.

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    Concrete Substrates for Accelerated Coral Restoration

    The concrete forms can be produced close to the site using simple materials and methods.

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    Concrete Substrates for Accelerated Coral Restoration

    Concrete is the ideal material for the coral substrate since it is a) heavy enough not to be swept away by tidal currents, b) calcium bicarbonate-based and thus conducive to the growth of the transplants, and c) strong enough to resist damage during the transplantation process.

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    Concrete Substrates for Accelerated Coral Restoration

    The concrete structures can be adjusted to optimize their placement in terms of access to light and avoiding strong currents.

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    Concrete Substrates for Accelerated Coral Restoration

    Meticulous data gathering continues to document the coral’s development.

  • Awards Silver 2005–2006 Asia Pacific

The Acanthasia project is a pioneering initiative in coral reef restoration, developed and implemented in the southern Philippines. Aimed at regenerating damaged marine ecosystems, the project introduces precast concrete reef modules designed to mimic natural forms while enabling coral attachment, regrowth, and the return of marine biodiversity.

By Ronald Rodriguez - Diamond Marketing, Cagayan de Oro, Philippines; Lemuel Alfeche and

The project is named after its central innovation: the “Acanthasia” module, a multi-legged, starfish-inspired concrete structure. Cast using cement rich in calcium bicarbonate, the material is biologically favourable to corals, supporting their settlement and early-stage growth. The geometry of the modules allows for sunlight penetration, seabed stability, and free current flow, creating ideal conditions for coral development and marine life return.

Concrete Substrates for Accelerated Coral Restoration

Project authors

  • RR
    Ronald Rodriguez

    Diamond Marketing

    Philippines

  • LA
    Lemuel Alfeche

    Philippines

  • OHC
    Oscar Halibas Cinco

    Philippines

Project Summary

The first phase, launched in mid-2004, involved six test structures deployed in Duka Bay and Cagayan de Oro. Three modules were seeded with coral fragments, while the other three were left unseeded to serve as controls. The results were clear: coral growth on the seeded modules was significantly faster, and the structures began to attract a growing variety of marine fauna — from fish to invertebrates — reinforcing the approach’s ecological value.

Concrete Substrates for Accelerated Coral Restoration

The “concrete starfish” prototype was first introduced in early-2000 at Duka Bay in the Southern Philippines. Project Update 2010.

The success of the trial led to proposed refinements for broader application. Planned upgrades included curved upper legs to reduce silt accumulation and an expansion from eight to ten legs to increase both structural integrity and surface area for coral settlement.

Concrete Substrates for Accelerated Coral Restoration

Its shape, with the eight elongated legs is reminiscent of a starfish.

Current Status

While formal updates on the project’s progression are limited beyond 2015, the Acanthasia project remains a formative example of how architecture, engineering, and marine science can converge to address ecological degradation. Its legacy continues to influence sustainable reef restoration efforts in the Philippines and beyond.

In the broader context of coral reef restoration in the Philippines, national programs and research initiatives have expanded the restoration toolkit, including:

  • The Filipinnovation Coral Reef Restoration Program, which established coral nurseries and focused on asexual coral propagation.
  • The ACIAR Coral Restoration Project, piloting mass larval reseeding and long-term ecological monitoring strategies.

While these efforts demonstrate the Philippines' ongoing commitment to marine habitat rehabilitation, specific information regarding the continued development or scaling of the Acanthasia project remains limited. Nonetheless, it stands as a formative example of how design-led ecological infrastructure can align material science, marine ecology, and architecture in service of environmental regeneration.

Jury Appraisal

The success of this project lies in its innovative focus on the marine ecosystem. Of particular merit is the effort to regenerate an endangered environment, an environment upon which many small coastal communities depend for their livelihood and future development. Such effort yields not only a positive impact on the natural surroundings by providing an ecologically effective catalyst for coral growth, but also an ethically affirmative social impact by increasing the quantity and diversity of fish species for nearby fishing communities.

Concrete Substrates for Accelerated Coral Restoration

The concrete forms can be produced close to the site using simple materials and methods.

This project convincingly demonstrates the value of simple, yet intelligent tools that are affordable, require little technical expertise, and can be easily replicated in different contexts. Also to be commended is the adaptability of the structures to the varied needs of local communities. The project signals sensitivity to economic issues by promoting a low-cost, incremental infrastructure rather than costly large-scale investments. This entry displays ingenuity in tackling a highly complex issue while offering a modest, but aesthetically refined design solution to the challenges at hand.

Project Updates

November 11, 2015 | Project Update | Cagayan de Oro, Philippines

Branching Out to Restore a Marine Ecosystem

Project update November 2015 – Concrete Substrates for Accelerated Coral Restoration, Cagayan de Oro, Philippines

Ten years after receiving the Holcim Awards Silver for Asia Pacific, the Concrete Substrates for Accelerated Coral Restoration project in the southern Philippines has shown remarkable success. Using starfish-shaped “Acanthasia” modules made from biologically friendly concrete, the initiative supports coral growth, marine biodiversity, and community livelihoods. As coral polyps steadily build reef structures, the project continues to demonstrate how design-led, scalable solutions can regenerate fragile ecosystems and sustain coastal communities.

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November 11, 2010 | Project Update | Cagayan de Oro, Philippines

Concrete Stars and Community Change

Field trials of the Acanthasia project in the southern Philippines continue to demonstrate the power of design-led ecological restoration. Despite funding challenges, the concrete “starfish” modules have successfully fostered coral growth and biodiversity in Duka Bay—sparking new economic opportunities in eco-tourism and shifting community attitudes toward environmental stewardship. The project’s impact extends beyond the reef, offering a replicable model for sustainable development and marine conservation.

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July 06, 2009 | Exhibition: Discovery 2009 – Water | Mainau, Germany

Acanthasia at the Nobel Laureates Exhibition: Sustainability Beneath the Surface

Showcased at the Discoveries 2009 – Water exhibition during the Nobel Laureates conference in Lindau, Germany, the Acanthasia project from the Philippines demonstrated how sustainable construction can extend beneath the ocean’s surface. Using starfish-shaped concrete modules to regenerate coral reefs, the Holcim Awards Silver-winning project highlighted the power of science, design, and community collaboration in restoring marine ecosystems and supporting local livelihoods.

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September 23, 2005 | Media Release | Beijing, China

Silver Award for Coral Restoration in the Philippines

Winner of the Holcim Awards Silver for Asia Pacific, the Acanthasia project received USD 50,000 for its innovative use of precast concrete modules to support coral regeneration in the Philippines. Designed by Ronald Roland Cesar Rodriguez, the project provides critical habitat for marine life while enhancing fish stocks for nearby coastal communities. Praised by the jury for its environmental and economic sensitivity, the project demonstrates how low-cost, incremental infrastructure can deliver tangible benefits for both ecosystems and livelihoods.

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Statements on Sustainability

  • The use of concrete substrates for rejuvenating coral reefs has proven to be more efficient, as the organisms exhibit a much faster growth rate compared to other materials. This accelerated growth is largely attributed to the presence of calcium—an ingredient in cement—which supports coral development. The design is innovative, addressing both the need for sunlight penetration essential to juvenile coral growth and ensuring seabed stability. The technology, from on-shore prefabrication to underwater installation, is relatively simple and can be easily replicated in other parts of the world to support coral reef restoration.

  • As a project purely aimed at marine ecosystem restoration, there are no ethical or social equity concerns. On the contrary, the experiment has had a tangible, positive impact on nearby fishing communities, with reported increases in catch of up to 100% as the newly formed reefs became habitats for a wide variety of fish species.

  • Both concerns are inherently addressed by the project’s nature. The restoration of ecological balance in marine environments is its primary purpose. Once installed, the structures require no fuel or energy input—each module becomes a self-sustaining ecosystem.

  • Each prototype module cost approximately USD 1,800. However, the economic returns have already been recouped through the increase in fish catch in the surrounding areas. Additional, less quantifiable benefits—such as income from scuba diving and eco-tourism—further support the viability of the project, though they were not included in the formal cost-benefit analysis.

  • An Acanthasia module on a barren seabed represents the beginning of a long process of marine life rejuvenation. Its aesthetic value emerges as nature takes over, repopulating the structure with varied marine species. This project is a contextual response to the environmental degradation caused by human activity—symbolically and practically using cement, derived in part from coral, as a medium to restore coral reef ecosystems.

Related information

Related Information

Location

pin Cagayan De Oro City, Misamis Oriental, Philippines

Cagayan De Oro City, Misamis Oriental, Philippines

News

Project update November 2015 – Concrete Substrates for Accelerated Coral Restoration, Cagayan de Oro, Philippines

Project Update

Branching Out to Restore a Marine Ecosystem

Cagayan de Oro, Philippines

Project Update

Tests sites grow coral and build knowledge

Cagayan de Oro, Philippines

Exhibition: Discovery 2009 – Water

Acanthasia project featured at the Nobel Laureates exhibition and conference 2009 in Lindau, Germany

Mainau, Germany

Holcim Awards

Prizes awarded to sustainable construction projects in Asia Pacific

Beijing, China