Restoration
CRF Coral Tree Nurseries
We raise corals in the ocean, in large-scale, Coral Tree Nurseries. In the ocean, corals are already adapted to the environment in which they will find a permanent home.
The Famous CRF Coral Trees
CRF invented the Coral Tree in 2011. Since then this simple, cost effective technology hs been widely recognized as one of the most cost effective and scalable methods for growing large numbers of branching corals as quickly as possible. The design has since been adapted for other species, and its evolution is ongoing.
Coral Tree Basics
Coral Trees are tethered to the ocean floor and buoyed with a subsurface float. They are suspended in the water column and move freely with wave surges and currents, which prevents damage to the tree structures and their corals.
The trees need to be cleaned regularly so that the corals do not have to compete with any other organisms for space or food. The trees are also raised and lowered depending on the season to ensure that the corals are kept in the most optimal conditions.
We now use three types of Coral Trees in our Nurseries.
The Original Coral Tree
Coral fragments are hung from the branches of the trees using monofilament line. Suspended in the sunlit and nutrient-rich water column, Branshing coral fragments will grow into “reef-ready” colonies in just six to nine months.
The Spiral Tree
We grow non-Acroporid species on Spiral Trees. Developed by other restoration practitioners as a new way of incorporating coral plugs into the original CRF Coral Tree, Spiral Trees help maximize our efficiency in non-Acroporid coral production. With 20 straight branches available to receive plugs, we can grow up to 400 corals on each Spiral Tree.
The Mega Tree
We use Mega Trees for holding non-Acroporid broodstock corals in our ocean-based gene bank. These were developed from our old Boulder Coral Tree design with the addition of new branches to the trunk, allowing for additional trays, which increased our capacity per tree from 240 to 480 plugs.
Dive into coral tree anatomy
The largest coral nurseries in the world
Our Tavernier Coral Tree™ Nursery off the coast of Islamorada is the largest in-situ, (or ocean based) coral nursery in the world, covering an acre and a half of ocean floor and containing more than 500 Coral Trees. This is one of network of Coral Tree Nurseries that stretch the length of the Florida Keys, raising corals to be rehomed on nearby reefs once they are big enough.
These nurseries have the capacity to raise more than 50,000 corals every year. These nurseries are also living laboratories where we collaborate with researchers to help advance the field of restoration science.
20
Coral species currently found in our Florida nurseries
600
Genotypes across coral species
1.5
Acres of ocean floor covered by the largest coral nursery in the world
Corals we work with
Restoring a coral reef ecosystem effectively means returning both species and genetic diversity to the wild. We are experts in the in-situ (ocean-based) propagation of Acroporids, bouldering corals, and pillar corals. In Florida we care for over 20 species in our nurseries, and around 600 genotyopes across these species.
Acroporids
The majority of our production stock consists of the branching corals Acropora cervicornis and Acropora palmata. These were once the dominant reef-building species in the Caribbean. Their populations have declined by around 98% in the last 40 years. Both are listed as “Threatened” under the U.S. Endangered Species Act, and as “Critically Endangered” on the IUCN Red List of Endangered Species.
Boulder corals
In 2023, we continued scaling up our propagation and restoration program for two species of bouldering star corals: Orbicella annularis and Orbicella faveolata. Bouldering species like star corals are important reef stabilizers. Within the past 20 years, Orbicella annularis has seen a greater than 50% decrease in its population and is now listed as “Endangered” on the IUCN Red List.
Pillar corals
We are one of a handful of organizations that has a propogation program for pillar coral, Dendrogyra cylindrus. We currently have 20+ pillar coral genotypes in the Tavernier Nursery. This species is now functionally extinct in the wild in Florida. In 2023, we aquired five new sexually recruited pillar coral fragments from the Florida Aquarium’s spawning endeavors, enriching the genetic diversity of our pillar corals’ brood stock.
other species
We are now propagating non-acroporid corals like Diploria labyrinthiformis, Montastrea cavernosa, and others, to boost the species diversity and resilience of our coral restoration efforts. This approach enriches nursery stocks, enhancing ecosystem stability and recovery capabilities, and underscores the integration of conservation and restoration efforts for sustainable reef ecosystems.
Gene Banks
Our coral nurseries are more than just hubs for active restoration—they are living repositories of genetic diversity. Every nursery we build includes gene-banking sections, safeguarding as many species and genotypes as possible. This genetic variety is the key to building resilience within coral populations, helping them adapt to changing ocean conditions and recover from disturbances.