Coral propagation sounds like something that requires a laboratory and a PhD. In practice, the core of it happens underwater, with a dive knife, a pair of cable ties, and a trained eye for what healthy coral looks like. I have watched it done by Dindo Paquibot in Maribago Bay with the same careful efficiency that a surgeon brings to a procedure. The instruments are simpler. The stakes are just as high.

How Coral Propagation Works

Corals can reproduce both sexually and asexually. Sexual reproduction involves spawning, where corals release eggs and sperm into the water column. Asexual reproduction occurs when fragments of a coral colony break off and reattach to new substrate, where they continue to grow as a genetically identical new colony. Coral propagation harnesses this natural asexual reproduction capacity to accelerate reef recovery.

Fragment Collection

Experienced divers collect small fragments, typically between 5 and 15 centimeters, from healthy donor colonies. Collection is done from the tips of branching corals, from areas of natural breakage, or from established nursery colonies that have been grown specifically for this purpose. Careful collection technique is essential to avoid damaging the donor colony.

Nursery Attachment and Growth

Fragments are attached to underwater nursery structures, which can be rope lines, metal frames, or tree-like structures made from PVC pipe or rebar. The nursery provides a stable substrate in a location with good water flow and appropriate light levels. Fragments are monitored every two to four weeks for algae overgrowth, disease, predator damage, and growth progress.

Outplanting

After 6 to 12 months of nursery growth, fragments that have reached sufficient size and health are transplanted onto prepared substrate at the restoration target site. They are attached using coral-safe epoxy or cable ties and photographed. The goal is to achieve sufficient density and diversity of coral cover to trigger natural recovery processes in the reef community.

Why Propagation Works in the Philippines

The Philippines is one of the best environments in the world for coral propagation because of its extraordinary coral diversity, warm clear waters, and the existing knowledge base of Filipino divers and marine scientists who have been practicing reef restoration for decades. The Coral Triangle contains more coral species than any other region on earth, which means there is a wider pool of donor genetics available and a higher likelihood that at least some species will show resilience to local conditions.

In 2019 our Director of Dive Operations Dindo Paquibot built and maintained coral nurseries and transplanted coral fragments into degraded reef zones in Cebu, with a Philippine reef restoration non-profit that has since dissolved. This is not theoretical expertise. It is hands-in-the-water experience at the exact sites where Reef Without Borders plans to operate.

Limitations and What They Mean

Coral propagation is not a solution to climate change. It cannot fix a reef that is bleaching every two years. It works best in combination with reduced local stressors, strong marine protected area management, and communities that are engaged in protecting the reef between restoration missions.

This is why Reef Without Borders will pair every restoration dive with documentation. We need to understand the conditions at every site we work before we plant, and we need to monitor what happens after we plant, so that we are investing in sites where restoration has a genuine chance of success and can provide data to others doing this work.

Clarisa Strohmeyer is the Founder and Executive Director of Reef Without Borders, a Houston-based nonprofit dedicated to coral reef restoration in the Philippines and across the Indo-Pacific. Learn more at reefwithoutborders.org/