Pillar coral is one of the most visually striking and biologically unique species in the Caribbean. It's the only coral in the region that grows as tall vertical columns rising from the seafloor — some individual pillars can reach several meters in height, creating a distinctive silhouette that no other Caribbean coral produces. It's also the only species in its genus (Dendrogyra), meaning it represents a completely separate evolutionary lineage from all other Caribbean corals. Unfortunately it's now also one of the most catastrophically threatened corals anywhere: since Stony Coral Tissue Loss Disease (SCTLD) reached Florida in 2014, the pillar coral population there has lost 94% of its coral tissue and 93% of its colonies, and NOAA reclassified it from Threatened to Endangered under the US ESA in December 2024. This post covers what pillar coral is, why it's biologically unique, what SCTLD did to it, and what active restoration efforts are attempting.
Identifying Pillar Coral
Pillar coral (Dendrogyra cylindrus) is unmistakable on the Caribbean reef because nothing else in the region grows this way. It's a digitate coral, meaning it resembles fingers (Latin digites) or a cluster of thick cigars rising vertically from the seafloor. Colonies begin as small encrusting bases from which one or more vertical columns grow upward. Individual columns are typically 5 to 25 centimeters in diameter and can reach several meters in height — some documented specimens have exceeded 3 meters tall. Unlike branching corals, the columns don't have secondary branches; each pillar grows straight up as a single continuous structure.
Color is typically brown, gray, or yellowish-brown from the zooxanthellae in the tissue. The surface of each pillar has a distinctive fuzzy or hairy appearance because — and this is the unique behavioral feature — the polyps are extended during daylight hours as well as at night. Almost all other Caribbean corals keep their polyps retracted during the day and extend them only at night to feed. Pillar coral's decision to keep polyps extended around the clock is unusual and gives the coral a visible "hairy" texture in daylight photography. This is one of the easiest ways to confirm identification: if you're looking at a vertical Caribbean coral column with a fuzzy tissue surface visible in daylight, it's pillar coral.
Distribution and Rarity
Pillar coral has a broad geographic range across the western Atlantic Ocean: Florida, Bahamas, Gulf of Mexico, Greater and Lesser Antilles, and much of the Caribbean Sea. But even within its natural range, it was always uncommon or rare. This isn't a species that formed dense stands like Acropora or dominant boulder colonies like Orbicella. Instead, pillar coral occurred as scattered individual colonies or small clusters, with substantial distances often separating one colony from the next. Even in reef areas where pillar coral was reasonably present, spotting one was still an event — divers who had explored Florida reefs for decades before 2014 would remember specific pillar coral colonies as landmarks.
Depth range is typically 5 to 25 meters, on both fore-reef slopes and reef flats where the substrate is stable enough to anchor the growing columns. In Florida, pillar coral was scattered throughout the Florida Reef Tract from the northern Keys down to the Dry Tortugas. In the Caribbean it's been documented in most reef ecosystems, though never abundantly.
The Reproduction Mystery
For decades, one of the strangest facts about pillar coral was that scientists could not find evidence it was successfully reproducing sexually. As we cover in our post on how corals grow, reproduce, and age, most corals produce sexually-derived juvenile colonies (recruits) that appear at new locations after successful fertilization and larval settlement. In over 30 years of Caribbean reef surveys, sexually-produced pillar coral recruits were essentially never found — not on Florida reefs, not in the Bahamas, not anywhere. Colonies appeared to persist entirely through vegetative growth of the columns themselves, with no visible sexual reproduction producing new colonies.
This mystery began to resolve when the first observation of a spawning male pillar coral was made in 2006, followed by the first documentation of a mass spawning of multiple males and females in August 2012 in Curaçao. Researchers subsequently established laboratory fertilization protocols and successfully reared larvae to primary polyp settlers. But natural recruitment rates in the wild remain essentially undetectable, meaning the species depends almost entirely on the continued survival of existing adult colonies. When those colonies die from disease, they aren't naturally being replaced.
The SCTLD Catastrophe
Stony Coral Tissue Loss Disease (SCTLD) first appeared in Florida in 2014 and immediately proved to be catastrophic for pillar coral. The disease is highly aggressive on this species, causing rapid tissue loss that advances across a colony in days rather than weeks or months. Because pillar coral colonies are typically isolated and the disease is waterborne, even geographically separated colonies were successively infected as the SCTLD outbreak expanded through Florida reefs.
The documented losses in Florida between 2014 and 2020 are staggering: 94% loss of coral tissue, 93% loss of colonies, and 86% loss of genotypes. In practical terms, this means the pillar coral is now functionally extinct on the Florida Reef Tract — a species that was uncommon but reliably visible before 2014 has essentially been eliminated as a viable wild population. As SCTLD has spread through the Caribbean, similar catastrophic losses have followed in every region the disease has reached. The pathogen responsible has not been definitively identified, though it appears to be bacterial and to spread through the water column.
Current Status: US ESA Endangered as of 2024
Pillar coral was first listed as Threatened under the US Endangered Species Act in 2014, at the same time as other Caribbean corals including staghorn, elkhorn, and the three Orbicella species. But the catastrophic losses to SCTLD after that listing prompted NOAA Fisheries to review the species' status, and in December 2024 pillar coral was formally reclassified from Threatened to Endangered under the ESA — the higher-risk designation. On the IUCN Red List, pillar coral is listed as Critically Endangered, one step below Extinct in the Wild. The species has probably experienced the most severe rapid population loss of any Caribbean coral, with the timeline compressed into roughly a decade from initial SCTLD emergence to functional extinction in significant portions of its range.
Restoration: Emergency Genetic Rescue
Because pillar coral has virtually no natural recruitment and remaining wild colonies are so few, restoration for this species has taken a different form than for staghorn or elkhorn. Rather than the fragment-based nursery model that works so well for fast-growing Acropora species, pillar coral restoration has focused on emergency genetic rescue — collecting fragments from remaining wild colonies before disease reaches them, maintaining them in aquarium facilities as living genetic archives, and using laboratory spawning induction and larval rearing to produce new colonies that might eventually be outplanted.
The Florida Coral Rescue Project, coordinated by the Florida Fish and Wildlife Conservation Commission and involving multiple aquarium partners including the Florida Aquarium's Center for Conservation, has collected and maintained pillar coral genotypes from throughout the Florida range. Researchers at institutions like Mote Marine Laboratory, SECORE International, and various Caribbean-region programs have been developing spawning induction protocols and probiotic treatments for SCTLD-affected corals. The scientific and technical progress is real, but the species-level challenge remains enormous: extraordinarily few remaining wild colonies, virtually no natural recruitment, an active disease still spreading through the Caribbean, and a species that requires very specific reef substrate conditions to survive.
Can You See Pillar Coral in Punta Cana?
Honest answer: probably not, and increasingly unlikely as SCTLD continues its Caribbean spread. Pillar coral was always rare throughout the Caribbean, including on our regional reefs. Some scattered colonies may persist in the wider Dominican Republic reef system, but at our Cabeza de Toro dive sites specifically, pillar coral is not something we can promise you'll see. If you happen to encounter a colony (or a distinctive vertical column that might be pillar coral), it's a significant find worth pausing to observe. It represents one of the most biologically unique and now most critically threatened corals in the entire Caribbean.
If you're diving anywhere in the Caribbean and think you've spotted pillar coral, sustainable diving practices matter enormously. Given how few colonies remain and how vulnerable they are to physical damage combined with disease stress, any accidental contact could be permanently consequential for that individual colony. Maintain excellent buoyancy, keep meaningful distance, don't touch, and consider photographing the colony and reporting its location to local marine research or conservation organizations — genetic sampling of any remaining wild colonies is valuable data for restoration programs.
The Bottom Line
Pillar coral (Dendrogyra cylindrus) is unique on Caribbean reefs — the only coral in the region that grows as tall vertical columns, the only species in its genus, and behaviorally unusual because its polyps stay extended during daylight hours as well as at night. Even at its historical best it was rare across the Caribbean, and since 2014 SCTLD has driven catastrophic losses — 94% coral tissue loss and 93% colony loss in Florida — leading to functional extinction on the Florida Reef Tract and reclassification from US ESA Threatened to Endangered in December 2024. Restoration efforts focus on emergency genetic rescue rather than large-scale nurseries because natural recruitment is essentially undetectable. Your chances of seeing pillar coral on a Punta Cana dive are low but not impossible. If you do spot what looks like one, it's a significant marine biology encounter. To learn more about coral biology and Dominican reef conservation efforts during a diving trip, message us through our contact form with your dates and questions.
