Massive Lobe Coral, Pavona gigantea

Massive Lobe Coral, Pavona gigantea. Underwater photographs taken in Bahía de La Ventana, La Paz, Baja California Sur,  in Bahia La Ventana, El Sargento, March 2025. Photographs courtesy of Aaron Woodrow, Juneau, Alaska. Identifications courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuerto-Vallarta/videos.

Massive Lobe Coral, Pavona gigantea. Underwater photographs taken in Bahía de Banderas, Puerta Vallarta, Jalisco, July 2026. Photographs and identifications courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuertoVallarta/videos.

Phylogeny:  The Massive Lobe Coral, Pavona gigantea (Verrill, 1869), is a colonial coral that is a member of the Agariciidae Family of Stony Coral. The Pavonas Genus is one of twenty-three genera in the Agariciidae Family, and there are twenty-one recognized species in the Pavonass Genus. They are also known as the Leaf Coral and the Plate Coral, and in Mexico as Coral Gigante or under the more generic name Coral Pétreo.

Habitat and Distribution:  The Massive Coral are found in shallow, protected, rocky substrate at depths up to 25 m (65 feet). They avoid high energy locations. The Massive Coral is a subtropical to tropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean from Concepcion Bay, south to Cabo San Lucas, Baja California Sur, in the Sea of Cortez and along the coast of the mainland south to Guatemala.

Morphology:  The Massive Lobe Coral is a colonial organism that forms large, massive, encrusting, or plate-like colonies that is composed of thousands of individual polyps. They can reach more than 1.0 m (3 feet 3 inches) in height and may build patches that are hundreds of square meters. They have massive, thick walled and well defined individual corallies, and highly dense skeletons that allows it to buffer acute stress better than most corals. Their linear growth rate is relatively slow, typically expanding by 0.9 to 1.2 cm per year. While its vertical or outward skeletal extension is slow, it is highly efficient at internal calcification and building dense reef structures which occurs at a much faster than in other Eastern Pacific corals. The male colonies grow faster than the female colonies with overall average growth being approximately 1 cm (0.4 inches) per year. Thrive during cold water upwelling events which have low pH and low aragonite saturation to the surface. They also thrive during periods of high light availably. The Massive Lobe Coral extend their polyps for feeding day and night giving them a fuzzy appearance.  Also at night Pavona Corals can send out “sweeper” tentacles (mesenterial filaments that are stomach tissue full of digestive enzymes), that can reach 30 cm (12 inches) in length, as a defense mechanism against space encroachment and to supplement their diet. As their individual polyps are much larger than those of other branching or encrusting corals (such as Pocillopora), Pavona gigantea uses these elongated tentacles to capture zooplankton at a significantly higher rate, granting it a massive advantage in heterotrophic feeding.  Corals from Pavona Genus are involved in “coral warfare” where they are generally agressive, however, in direct space conflicts with neighboring corals like Pocillopora, studies have snown Pavona often relies on deploying their mesenterial filaments from its large polyps to digest rival tissue, rather than relying strictly on elongated polyps. The Massive Coral are typically brown, gray or green.  The Massive Lobe Coral can be confused with the Peacock or Leaf Coral, Pavona explanulata, which has similar corallite structures, but does not form massive colonies.

Ecosystem Interactions:  This species, along with the Potato Coral, Sholder Blade Coral or Swollen Coral, Pavona clavus and the Lobed Coral, Porites lobata, can build reef frameworks or contribute to pocilloporid reef building. As the outer edges of the Massive Coral plate colony remain thin, the species has become a key target for nurseries for other corals and conservation initiatives. Massive Corals have a symbiotic relationship with zooxanthellae as described above. The majority of corals undergo parasitized by trematodes (flatworms) and polychaetae worms however such attacks on the Massive Coral has not been formally documented. In response to El Niño events they experience reproductive cycle disruptions and divert energy to tissue repair and starvation survival. Post El Niño events they also become prone to attack by the Crown-of-Thorns Sea Star, Acanthaster planci, and to bioerosion by Boring Sea Urchins. As a zooxanthellate coral it obtains energy from the zooxanthellae and in return provides the host with nutrients, carbon dioxide, and a secure, sunlit, platform for the zooxanthellae.

Predation: Post El Niño events the Massive Lobe Coral  become prone to attacks by the Crown-of-Thorn Star Fish, Acanthaster planci,  and to bioerosion by Boring Sea Urchins. Such attacks that have wiped out large areas of coral reef habitat. The effects of these outbreaks include the reduction of abundance and surface cover of living coral, reduction of species diversity and composition, and overall reduction in habitat area.

Diet:  The Massive Lobe Coral is a zooxanthellate coral that has a symbiotic relationship with zooxanthellae (single-cell dinoflagellates in the Symbiodiniaceae Family) produce starches and sugars by means of photosynthesis and these carbohydrates are passed along to their hostss, providing the majority of the host’s total energy needs. They are also sessile suspension feeders that extend their small tentacles during dalylight hours to capture drifting eggs, larvae and plankton from the water column.

Reproduction:  The reproduction of the Massive Lobe Coral relies heavily on high-synchrony sexual reproduction. Colonies that reach 11 years of age and 10 cm in diameter are sexually mature shifting its resources from growth toward gamete production. The are predominately gonochoric (dioecious) where individual colonies are either male or female. Some populations exhibit a flexible strategy where colonies begin their reproductive lives as males and later transition into hermaphrodites. This shifting mechanism is an evolutionary adaptation that maximizes genetic diversity and ensures successful cross-fertilization even in isolated reef patches. They also reproduce as a synchronized daytime broadcast spawners whereby both male and female colonies release millions of eggs and sperm clouds simultaneously into the open water column that are fertilized externally. The zygotes develop into free-swimming, planktonic planula larvae. These larvae drift with ocean currents before settling onto shallow, rocky substrates to morph into a new polyp and start a new colony. They can also reproduce asexually where fragments are broken off my physical damage such as storm serge, anchors or bioerosion by reef animals. The lifespan of the Massive Lobe Coral has not been documented.

Human Interactions:  From a conservation perspective the Massive Lobe Coral is widespread but uncommon with declining populations and is currently considered to be Near Threatened. They are abundant in some regions and very sparse in others. They are the focus of several conservation efforts to restore their populations. Restoration projects cut this coral into tiny pieces to stimulate rapid healing and clonal tissue growth. Massive Corals are collected on a limited basis for the aquarium trade. Pavona species have a high sensitivity to extreme elevated temperatures that interfere with reproduction and recruitment. The 1982-83 El Niño event caused reef mortalities of up to 97% in some areas. Their long-term viability is threatened by ocean acidification, coastal development, overexploitation and destructive fishing practice, inland pollution and dredging and erosion producing high levels of siltation, and marine pollution have also had negative impacts on Pavona Coral. A slow growth rate, infrequent asexual fragmentation and global climate change have led to bleaching and increased susceptibility to Stony Coral Tissue Loss Disease.  Bleaching, also known as seasons, occurs in annual cycles at some level during the summer warm-water months and the corals recover through the winter when the water temp cools down.

Snonyms:  Pavonia gigantea.