Corals

From above, the scale of an in-water nursery is self-apparent.
Photo credit: Jack Fishman

Coral Propagation and Outplanting

Our partners use a variety of methods for growing (coral propagation) and outplanting genetically diverse and resilient corals. Collectively, they boast hundreds of in-water nurseries with various structure types; hundreds of land-based coral propagation raceways, cutting-edge facilities and innovative research to help understand and address threats help promote thriving reef ecosystems at the SEVEN ICONIC REEF SITES.

Mission: Iconic Reefs field team members assist in site preparation and removal of nuisance species that threaten thriving coral ecosystems.

The Coral Restoration Foundation nursery is home to thousands of future reef-building corals.
Photo credit: Jay Clue

Ocean-based Propagation

Partners have developed multiple different methods of growing and propagating both branching and massive corals in ocean based nurseries that host similar conditions to those on the reef. Different structures provide the appropriate conditions for efficiently growing the corals. Corals are primarily asexually propagated through fragmentation creating multiple new copies of individuals to increase coral abundance quickly.

As the impacts of climate change are expected to continue for years to come, Mission: Iconic Reefs partners have been trialing interventions to improve survival of nursery corals during bleaching events such as the one induced by the summer 2023 marine heatwave. Practitioners have trialed deployment of shading structures that both lower the temperature of the water beneath them and reduce the amount of direct sunlight, which together contribute to coral bleaching.

FKNMS_Reef_MIR_Coral Nursery_Credit_MattMcIntoshNOAA_07 (1)

The Coral Restoration Foundation nursery is home to thousands of future reef-building corals.
Photo credit: Jay Clue

Raceways like this one can grow hundreds of coral fragments until they are large enough for outplanting.
Photo credit: Jay Clue

Land-based Propagation

Some partners propagate corals on land using shallow-water raceways with carefully maintained water quality to maximize growth and isolate the corals from the potentially harmful events that happen in the wild like bleaching events and hurricanes. Land-based facilities also provide stable conditions for sexual propagation creating offspring with new genetic combinations.

Coral Outplanting

There are many outplanting methods that our partners employ to place the propagated corals onto the reef. Different methods are optimized for different species and reef conditions. But all use some sort of adhesive (e.g, epoxy, cement) to attach the corals to clean reef substrate.

These elkhorn coral outplants were adhered to existing structure at Horseshoe Reef by the Coral Restoration Foundation.
Photo credit: CRF

Eureka! M:IR field team members are testing the use of an underwater algal tool device that suctions material from the seafloor.
Photo credit: Jay Clue

Site Preparation

Unlike previous restoration efforts, M:IR involves a comprehensive ecosystem restoration strategy beyond coral outplanting. Similar to tending a vegetable garden, trained coral gardeners must prepare a site for outplanting by removing the underwater version of weeds — fleshy algae, encrusting invertebrates, cyanobacteria, gorgonians, and sea fans — to allow the coral fragments to attach successfully. Site preparation and substrate conditioning remove nuisance algal and invertebrate species and expose the underlying crustose coralline algae colonized reef framework before any coral transplanting occurs.

Snail Removal

Small in size, large in number, when corallivorous snails (Coralliophila galea) invade a coral landscape they can overwhelm their prey, just like insects can overwhelm plants. Recently fragmented corals release mucus containing chemicals that attract snails and may help them find and colonize new outplants within a few days. Snail feeding is a common source of coral tissue loss, and in some genera, removing them has resulted in a significant increase in the area of live coral tissue in comparison to areas where the snail clusters were left untouched. Mission: Iconic Reefs field team members occasionally visit coral outplant sites to remove these nuisance species, often collecting as many as 1,000 on each mission.