Project title: Fighting coral diseases with probiotics in the Caribbean region

Project lead: Dr. Valeria Pizarro

Co-applicants: Maria Fernanda Maya, Blake Ushijima, Nacor Bolaños, Dr. Sarah Gignoux-Wolfsohn, Dr. Elvira Alvarado

Countries involved: United States of America and Colombia

Takes place: San Andrés (Colombia)

Supporting institutions: Perry Institute for Marine Science, University of North Carolina Wilmington, University of Massachusetts Lowell, Blue Indigo Foundation, CORALINA, ECOMARES Foundation

Total budget: USD $1,499,388.30

Duration: 36 months

Project overview

Coral reefs in the Caribbean face many threats, including climate change, pollution, and the spread of diseases. The Stony Coral Tissue Loss Disease (SCTLD), in particular, is devastating coral reefs throughout the region, accelerating their decline and threatening marine ecosystems. Individual coral colonies may be saved with antibiotic treatment, but this does not prevent new lesions nor disease transmission. This is highly problematic for any coral restoration efforts, especially since this disease is waterborne and undetectable in the water column. Probiotics are a promising alternative since they can protect healthy colonies, stop lesion progression, and prevent disease transmission. This project focuses on identifying and deploying beneficial bacteria as probiotics to increase coral resistance, growth, and reproduction in San Andrés, Colombia. By combining probiotic treatments with a coral restoration program, the project ultimately aims to create disease-resistant reefs that will sustain local livelihoods and preserve these critical ecosystems for future generations.

Specific objectives

1. Evaluate the spread of the Stony Coral Tissue Loss Disease (SCTLD) in San Andrés and identify resistant corals of four key species.
2. Isolate, develop, and test potential probiotic bacteria that promote disease resistance.

How the objectives will be met

• Disease spread evaluation: direct coral counting and high resolution underwater photos of corals will be used to gather information on how this disease is affecting San Andrés’ coral populations (e.g., disease infection, survival).
• Coral sampling: collect tissue and mucus from corals of four species (Diploria labyrinthiformis, Pseudodiploria strigosa, Orbicella faveolata, and Montastraea cavernosa) to identify bacterial biomarkers for disease resistance.
• Probiotic screening: several traits of the bacteria with potential probiotic effects will be analyzed, including physiological and biochemical characteristics. Based on this data, probiotic candidates will be selected.
• Safety testing: toxicity tests will be run to ensure probiotic candidates do not harm other coral-dependent organisms and larvae.
• Probiotic trials: further trials will be carried out at the San Andrés coral facility to compare the effectiveness of probiotics versus
• Field testing: at least 8 probiotic candidates will be tested in San Andrés. Each probiotic candidate will be applied to treat coral larvae and fragments, which will then be transplanted to restore reefs that will be closely monitored.
• Local capacity building: training on local larvae propagation, probiotics testing, and probiotic production will be offered at the San Andrés coral facility and the University of North Carolina Wilmington.

Impact of the project

This project will directly benefit San Andrés by advancing the understanding of Stony Coral Tissue Loss Disease (SCTLD) in the region, developing effective probiotic treatments, and restoring its degraded reefs, ultimately contributing to the preservation of the local marine biodiversity and livelihoods.

The probiotics developed by this research will be available to conservation and research organizations across the Caribbean, empowering them with effective tools to combat this disease in the field.

Major highlights

• Development and testing of probiotics to enhance coral resistance to the Stony Coral Tissue Loss Disease (SCTLD).
• 500 coral colonies treated with probiotics and transplanted to San Andrés reefs.
• Colombian partners will be able to produce the probiotic treatment in San Andrés island.

In 2024:

✅ Grown 2,200 corals for outplanting in 2025.
✅ Trained 20 students and researchers.
✅ Trained local communities in coral microfragmentation techniques.
✅ Established the first-ever coral larval rearing facility in San Andrés, Colombia.

To learn more about this project, watch the episode 8 of our web series.