Corals In Our Nurseries

Coral gardening is the technique used by RRFB to propagate via fragmentation different species of branching and massive corals. Originally RRFB collected several samples of each coral species, called broodstock colonies, from around Bonaire and Klein Bonaire to ensure not only a diversity of species, but also diversity within each species. By working with several species and genotypes within the restoration sites, RRFB is poised to ensure reef health and increase its resilience.

Branching Corals

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.

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Elkhorn coral (Acropora palmata)

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.

Boulder Corals

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 (Orbicella faveolata)
Mountainous star coral (Orbicella faveolata)

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.

Great star coral (Monastraea cavernosa)