Massive Lobe Coral, Pavona gigantea

Massive Lobe Coral, Pavona gigantea. Underwater photographs taken in Bahía de La Ventana, El Sargento, Baja California Sur, 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. Note: the photo just above is a badly bleeched Pavona gigantea, a fairly common encounter currently in Puerta Vallarta.

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 Concepción 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 corallites, and highly dense skeletons that allows it to buffer acute stress better than many other coral species. 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. They thrive during cold water upwelling events which bring a lower pH and aragonite saturation to the surface. They also thrive during periods of high light availability which is directly affected by water clarity and the depth at which the coral is growing. The reason being is the zooxanthellae, the symbiotic algae they host needs light for their photosynthesis process. The Pavona gigantea corals are typically found in various shades of brown, gray or green and extend their polyps for feeding day and night giving them a fuzzy appearance. This Massive Lobe Coral can be confused with Porites lobata from a distance because they can both become massive colonies that grow in the same region but a closer inspection will show their similarities end there as the polyp structure and growth forms are quite different.

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. As mentioned, Massive Lobe Corals have a symbiotic relationship with zooxanthellae. In response to El Niño events they experience reproductive cycle disruptions and divert energy to tissue repair and starvation survival. As a zooxanthellate hosting coral, it obtains nutrients from the zooxanthellae and in return provides the zooxanthellae with carbon dioxide, and a secure, sunlit, platform for the photosynthesis process. They also are quite aggressive and can protect their territory by sending our destructive sweeper tentacles to attack competing species as discussed below.

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) which produce starches and sugars by means of photosynthesis and these carbohydrates are passed along to their hosts, providing a large portion of the host’s energy needs. They are also sessile suspension feeders that extend their polyps to capture drifting eggs, larvae and plankton from the water column. Also, most often at night Pavona sp. 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 polyps 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 shown Pavona often deploy their mesenterial filaments from its large polyps to digest rival tissue, which also helps to supplement their diet.

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 (3.9 inches) 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 often utilize coral fragments that were broken off the mother colonies which they refer to as fragments of opportunity and they can often get multiple smaller clones or “frags” from those to replant so they can grow into new colonies. 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 many negative impacts such as ocean acidification, marine pollution, coastal development, overexploitation and destructive fishing practices. Various inland pollutions often get to the sea via rivers. Dredging and erosion produce high levels of siltation which can settle on the coral, smother the polyps and reduce their ability to feed properly. A slow growth rate, infrequent asexual fragmentation makes this coral species somewhat slow to recover if damaged. Bleaching occurs in annual cycles at some level during the summer warm-water months and increases the susceptibility to tissue loss through necrosis and disease. Fortunately, after the water temp cools back down through the winter months Pavona gigantea colonies can use this time to heal and keep growing.

Snonyms:  Pavonia gigantea.