Coral propagation by fragmentation is the restoration technique that we began our project with in 2012. This method is based on the asexual reproduction of corals and allows us to harness the natural process of fragmentation to propagate large numbers of corals. It enables us to produce thousands of corals without harming the wild populations. By utilizing fragmentation, we can quickly restore coral populations using a well-established approach that has been used for years by reef restoration programs worldwide.
Today our nurseries reach both coasts of Bonaire and Klein Bonaire, with the total capacity to host over 23,000 corals. Each coral morphology is different and therefore there is no “one size fits all” approach. Depending on the species, corals are either hung from the branches of the trees or secured on trays.
Pop-up nurseries
We are always looking for innovative ways to scale up our restoration efforts. Nurseries that are installed temporarily next to an outplanting site, called pop-up nurseries, allow more time for corals to acclimate to the site conditions before being outplanted. Furthermore, by eliminating coral transportation between nursery and outplanting sites, these nurseries simplify logistics and reduce the stress on corals. After 2-3 years the nursery is removed and relocated to a new restoration site, leaving no trace behind.
Outplanting on the reef
Corals are selected in the nursery to be outplanted to the reef once they are “reef-ready”. This means their age, size, and overall health, makes them better-suited for survival when exposed to stressors that exist in greater abundance outside of a nursery environment. Genetically diverse corals are then tagged, taken to a selected restoration site, and outplanted back to the reef, using various methods.
Depending upon the species of coral and the environmental conditions of the reef, a variety of outplanting methods are used. Careful consideration goes into choosing an outplanting site and the method.
Corals in our nurseries
Staghorn Coral
Scientific Name: Acropora cervicornis
IUCN Status: Critically Endangered
# Genotypes in Nursery: 25
Staghorn coral used to be a major reef-building Caribbean coral species and, like elkhorn coral, is a shallow-water, branching coral that can form massive thickets. It is one of the fastest growing stony corals in the Caribbean. Thickets of staghorn provide shelter to many species of reef fish, especially juvenile fish. These corals prefer to grow in the “Staghorn Zone” from 5 – 15 meters of depth. Staghorn coral is particularly threatened by disease and bleaching in addition to reduced reproductive success due to geographic isolation, as once-massive thickets die off and only small patches remain. As a result of many threats and massive die-off, staghorn coral is at a high risk of extinction.
Elkhorn Coral
Scientific Name: Acropora palmata
IUCN Status: Critically Endangered
# Genotypes in Nursery: 25
Elkhorn coral, along with staghorn coral, was a predominant reef-building coral in the Caribbean until its rapid die-off in recent decades. It is a shallow-water, branching coral that provides an important habitat for reef-dwelling fish species, both mature and juvenile. Elkhorn coral likes to grow in depths of 0 – 5 meters, where its strong branches help break the force of wave action along the coast. In fact, sometimes colonies grow so shallow that they become exposed at low-tide. Due to a combination of disease and environmental impacts, the species has declined since the early 1980s to less than 3% of its former abundance. Without immediate action, our reefs stand to lose this species.
Lobed Star Coral
Scientific Name: Orbicella annularis
IUCN Status: Endangered
# Genotypes in Nursery: 12
Lobed star coral is one of the five major reef-building Caribbean corals, becoming more predominant as species of branching corals have collapsed in recent decades. Although they may not look like a star from afar, star corals take their name from the star-shaped pattern of their corallites. Until the mid-1990s lobed, mountainous, and boulder star corals were thought to be one species, Monstatraea annularis, that altered its form to available light conditions. Molecular analysis has since shown that these corals are indeed separate species. Lobed star coral grows from depths of 0 – 80 meters and takes the shape of several columns, or lobes, clustered together. This species has the largest average colony size of any coral species and plays an important role in protecting shorelines from surge. This species is susceptible to bleaching and is at risk of extinction due to mature coral heads dying off faster than new heads are formed.
Mountainous Star Coral
Scientific Name: Orbicella faveolata
IUCN Status: Endangered
# Genotypes in Nursery: 12
Mountainous star coral is one of the five main reef-building corals of the Caribbean. While its star-shaped polyps may look similar to those of lobed star coral, mountainous star coral can be identified due to its large, continuous shape that may be punctuated by peaks and valleys. This coral is often a deep brown with florescent green or yellow highlights. Its ideal depth range is 10 – 20 meters, but this coral can be found up to depths of 40 meters. Due to its size and encrusting nature, mountainous star coral stabilizes reefs while adding mass. The species is greatly affected by bleaching because it subsists nearly entirely off of photosynthesis rather than also capturing prey from the water. Additionally, mountainous star coral takes a long time to reach sexual maturity, 3 – 8 years, in comparison to its average life-span of 10 years. Both of these facts put it at risk of die-off.
Great Star Coral
Scientific Name: Montastraea cavernosa
IUCN Status: Least Concern
# Genotypes in Nursery: 12
The only species belonging to the genus Montastraea, great star coral is easily distinguished from other star corals by the large size of its individual polyps, which are often about the size of a thumb nail. Great star coral forms heads up to 2.5 meters in diameter and can live anywhere from 0 – 90 meters of depth; they are often the predominant coral species between depths of 12 – 30 meters. While they tend to grow in small mounds at shallower depths, coral heads of this species can become more plate-like at deeper depths. This coral comes in a variety of colors, such as dark brown, light brown, and white; and can even take on a red or orange florescent sheen during the day. The coral may resemble a bumpy boulder during the day, but at night the coral is often seen with its polyps extended in order to feed.
Maze Coral
Scientific Name: Meandrina meandrites
IUCN Status: Critically Endangered
# Genotypes in Nursery: 12
Maze coral is a stony coral species found primarily throughout the Caribbean Sea and Gulf of Mexico. It’s easily identifiable by its distinct, wall-like ridges called “corallites”, mini structures of calcium carbonate secreted by each polyp. M. meandrites has been observed to withstand challenging environments, namely water with high turbidity and sedimentation. Though they usually prefer depths of 8 – 30m, colonies can survive anywhere between 1-80m. Listed as Critically Endangered on the IUCN Red List, maze coral has suffered major population declines due to the widespread impact of Stony Coral Tissue Loss Disease (SCTLD). Prior to the introduction of this disease throughout the Caribbean, the species was categorized as Least Concern.
Pillar Coral
Scientific Name: Dendrogyra cylindrus
IUCN Status: Critically Endangered
# Genotypes in Nursery: 5
Pillar corals are a type of stony coral found in tropical regions throughout the western Atlantic, usually as deep as 20 meters (65 ft). True to their namesake, pillar corals build tall, vertical structures that can reach up to 3 meters high. Their unique morphology not only provides important habitat for fish and other reef creatures, but also creates a barrier to absorb the impact of storm surges before they reach shore. Their polyps sometimes feed during the day, one of the few species of hard-corals that have been observed doing so. This species is listed as Critically Endangered on the IUCN Red List, due to a number of broad and local-scale threats. Low recruitment and survival rates in juveniles, susceptibility to diseases, and damage from hurricanes and tropical storms collectively contribute to its status. Like many other Caribbean coral species, Stony Coral Tissue Loss Disease has caused localized extinction in many regions – including large-scale extinction in Florida.
Elliptical Star Coral
Scientific Name: Dichocoenia stokesii
IUCN Status: Vulnerable
# Genotypes in Nursery: 6
Elliptical star coral, also known as pineapple coral, inhabits reefs throughout the Caribbean. It prefers depths of 5-20m, but can be found up to 70m deep if enough light is available. This uniquely shaped coral has elongated, characteristically oval polyps that provide shelter for small fish and invertebrates. Though it’s heat tolerance is relatively high compared to other stony coral species, Dichocoenia stokesii is highly susceptible to Stony Coral Tissue Loss Disease (SCTLD) and other triggers of bleaching. This species is listed as vulnerable on the IUCN Red List, with recent declines in its population primarily attributed to slow growth rates and limited reproduction in the face of SCTLD.
Symmetrical Brain Coral
Scientific Name: Pseudodiploria strigosa
IUCN Status: Critically Endangered
# Genotypes in Nursery: 12
Symmetrical brain coral is a colonial type of stony coral growing at depths of up to about 40 meters (130 ft). Its namesake “brain-like” dome can reach almost 2 meters (6 ft) in diameter, acting as structural reinforcement for any reef it’s a part of. This widespread brain coral species occurs throughout the Caribbean Sea and Western Atlantic, and can sometimes be found on muddy stretches of seabed or degraded reef. P. strigosa grows very slowly, adding only about 1 centimeter (0.39 in) to its diameter per year. Unfortunately, it’s slow growth rate doesn’t bode well for natural recovery following disease events, like Stony Coral Tissue Loss Disease (SCTLD). Just like many other stony coral species, SCTLD has caused significant mortality in many populations of symmetrical brain coral. Because of SCTLD and other climate-related threats, this species is considered Critically Endangered on the IUCN Red List.
Blade Fire Coral
Scientific Name: Millepora complanata
IUCN Status: Critically Endangered
# Genotypes in Nursery: 3
Blade fire corals are coral-like colony builders that can be found in most of the Caribbean Sea at shallow depth (0-15mt, 1-45ft of depth). Despite their name and appearance, fire corals do not pertain to the coral class, but rather to Hydrocorals of the class of Hydrozoans. Millepora colonies grow by forming vertical blades of up to 50 cm (20 in) of height; these plates face in a direction perpendicular to the local current, enabling the colony to withstand turbid waters and strong surges. Their reproduction involves alternating asexual and sexual cycles and, given their sturdy nature, these fire corals are one of the first organism to recolonize damaged reef. The species has been listed as critically endangered by the IUCN since a massive bleaching event that happened in 1998; however, M. complanata has shown possibilities of recovery from bleaching, even months after the occurrence.
Boulder Brain Coral
Scientific Name: Colpophyllia natans
IUCN Status: Vulnerable
# Genotypes in Nursery: 6
Boulder brain corals, also known as large-grooved brain corals, are the only species in the genus Colpophyllia; they are stony corals that can be found down to 50mt (165ft) of depth but prefers to live in somewhat shallower waters. Despite having a slow growth rate, each colony can reach up to 2mt (7ft) in size, making it one of the dominant reef-building corals. This species can be found across the Caribbeans and the Gulf of Mexico; in these regions the colonies have shown great resistance to algal bloom and tempests and hurricanes, but are highly susceptible to bleaching: high water temperatures and solar radiation can cause the coral to bleach, thus becoming vulnerable to the White Plague disease or to black band disease, with a mortality rate of almost 50%. Some specimens have been found to be more than 200 years old, making it one of the most long-lived species of corals. We also focus our coral breeding efforts on these species, in addition to fragmentation. So, while we propagate 2 genotypes of Cnat in our nurseries via fragmentation, we’ve produced many more offspring of varying genetic backgrounds via coral breeding.
Grooved Brain Coral
Scientific Name: Diploria labyribnthiformis
IUCN Status: Critically Endangered
# Genotypes in Nursery: 5
Grooved brain corals are stony corals with a maze-like appearance and their grooves are smaller compared to the ones of the Boulder brain coral; this reef-building species is commonly found in the Western Atlantic Ocean and in the Caribbean Sea at a depth range of 1-40mt (3-98ft). Their growth rate is very slow, around 3,5mm (0,13in) per year, however they can reach up to 2mt (7ft) in diameter. D. labyrinthiformis is hermaphroditic and reproduces through broadcast spawning; unlike other similar corals, spawning events happen multiple times from late spring to mid-autumn. This species is susceptible to SCTLD and black band disease, which led the IUCN to give it the status of critically endangered. The coral also has a beneficial relationship with the long-spined see urchin (Diadema antillarum), whose grazing activity helps reduce the effects of shading and overgrowth by macroalgae. We also focus our coral breeding efforts on these species, in addition to fragmentation. So, while we propagate 5 genotypes of Dlab in our nurseries via fragmentation, we’ve produced many more offspring of varying genetic backgrounds via coral breeding.
Smooth Flower Coral
Scientific Name: Eusmilia fastigiata
IUCN Status: Critically Endangered
# Genotypes in Nursery: 4
Smooth flower coral is a stony coral native to Trinidad and Tobago that can be found in the Caribbean Sea, Gulf of Mexico and Southern Florida. The name comes from the distinctive shape the coral has at night when the polyps extend their tentacles to feed. The colony grows at a slow rate up to a diameter of 50cm (20in). These fascinating corals can be found down to 60mt (200ft) of depth, though they are more common between 5 and 25mt (15-82ft). E. fastigiata is a fragile coral species, susceptible to the white plague and to bleaching as a result of higher water temperatures and ocean acidification; overabundance of macroalgae can also be a threat and, finally, hurricanes and tempests can damage corals located at shallower depths. Despite being common throughout the Caribbean, the IUCN has recently updated its status to critically endangered, due to its expected high mortality rate and a noticeable decreasing trend in its population numbers.
Clubtip Finger Coral
Scientific Name:Porites porites
IUCN Status: Least Concern
# Genotypes in Nursery: 7
Clubtip Finger Coral (Porites porites) is a stony coral species found throughout the Caribbean Sea, thriving in shallow reef environments down to depths of 20 meters (66 ft). It forms curved, hook-shaped colonies with thick, finger-like lobes, which can grow up to 8 meters (26 ft) tall and 5 meters (16 ft) wide. Its branching structure provides shelter for small reef fish and invertebrates, playing a key role in reef ecosystems. While Porites porites is classified as Least Concern on the IUCN Red List, it remains vulnerable to coral bleaching, ocean acidification, and storm damage. Despite its relatively fast growth rate, the increasing frequency of climate-related stressors highlights the importance of conservation efforts to ensure its long-term survival.