Project title: Coral Recovery in the Face of Crisis: Locally Led biological innovation for reef resilience

Lead applicant: Maria Fernanda Maya

Co-applicants: Rubén Azcárate Molina, Yanelys Cantillo Villa

Countries involved: Colombia

Takes place: San Andrés, Colombia

Supporting institutions: Blue Indigo Foundation

Total budget: USD 99,967

Duration: 18 months

Project overview

Coral restoration in the Caribbean faces mounting challenges from two interacting stressors: the lethal, fast-spreading Stony Coral Tissue Loss Disease (SCTLD) and the overgrowth of macroalgae. First confirmed in San Andrés in 2022, SCTLD now affects both the east and west coasts of the island, while unchecked macroalgae proliferation further limits coral recovery by competing for space and light. Together, these threats reduce coral survival, hinder recruitment, and undermine the long-term success of outplanting efforts. They add to decades of decline caused by sea urchin die-offs, bleaching events, and earlier disease outbreaks that have fundamentally altered reef composition across the region. While branching species like Acropora can show survival rates of 60–70% in nurseries, less is known about massive coral species, which are rarely used despite their crucial role in providing reef structure and long-term ecosystem stability.

Promising new tools such as probiotics are emerging, but their use in the Caribbean is often limited by dependence on international expertise, equipment, and resources. This project seeks to change that by building practical, locally led solutions that directly strengthen coral resilience and restoration outcomes. The team will test methods to produce and apply probiotics on-site, empowering practitioners to boost coral survival after outplanting. At the same time, they will evaluate strategies to reduce macroalgae dominance through a mix of herbivore restoration and community-driven algae removal. Together, these actions aim to improve coral survivorship, restore critical ecological functions, and deliver scalable, accessible methods that can be adopted widely across the Caribbean.

Specific objectives

Improve coral transplant survival by testing two field-ready interventions:

1. The application of locally produced coral probiotics
2. Macroalgae control through sea urchin Diadema antillarum translocation and community-led algae removal.

How the objectives will be met

• Locally Produced Coral Probiotics: initiate probiotic culture and growth tests, carry out coral microfragmentation, rearing, and treatment with probiotics.

• Probiotics and Macroalgae Control: Establish ten 2×2 m plots at two reef sites, each with 40 coral fragments from 2–4 species. Treatments will be distributed as follows:
  • • 3 plots treated with probiotics only.
    • 3 plots with algae management only (sea urchin Diadema antillarum based control plus community-led algae removal).
    • 3 plots with combined probiotic and algae interventions.
    • 1 control plot with no intervention.
• Field Trial Monitoring: assess coral survival, coral growth, water quality, macroalgae cover, and reef fish diversity.

Impact of the project

• At least one protocol developed and tested, which is expected to achieve 60–70% survival of outplanted coral fragments 6 months.
• At least one treatment (probiotic, algae, or combined) shows a ≥15% increase in survival over the control.
• One functional and equipped facility to perform probiotics production.
• At least three local staff trained to culture and apply probiotics independently.
• 10 local actors engaged in algae removal, monitoring, or data collection.
• At least 40% decrease in visible macroalgae cover in algae intervention plots compared to control.
• At least 20% of translocated urchins remain within treatment plots after a month.
• Clear protocols developed and tested for both interventions.

Major highlights

• Establishment of local probiotic production, eliminating reliance on external sources.
• Active involvement of the local community, fostering ownership of their reefs.
• Strengthened capacity and skills within the local community.
• The project targets 2–4 coral species, including Orbicella faveolata and Pseudodiploria strigosa.