Red Sea Fan, Pacifigorgonia adamsii
Red Sea Fan, Pacifigorgonia adamsi. Sea fans collected in the greater Cabo San Lucas area, Baja California Sur. A fairly common by-catch of a bottom fisherman.
Red Sea Fan, Pacifigorgonia adamsii, Juvenile Incipient Colony. Underwater photograph taken in Bahía de Banderas, Puerta Vallarta, Jalisco, July 2026. Photograph and identification courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuerto-Vallarta/videos.
Red Sea Fan, Pacifigorgonia adamsii. Underwater photographs taken in Bahía de Banderas, Puerta Vallarta, Jalisco, July 2026. Photographs and identifications courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuerto-Vallarta/videos.
Phylogeny: The Red Sea Fan, Pacifigorgia adamsii (Verrill, 1868), is an octocoral and a member of the Gorgoniidae Family of Gorgonians of soft corals. The Pacifigorgia Genus is one of thirteen genera in the Gorgoniidae Family, and there are thirty-seven species in the Pacifigorgia Genus. The genera within the Gorgoniidae Family are separated by the degree and type of spiculation, along with the pattern of branching and the morphology of the colony as a whole. They are known in Mexico as Abanico Rojo de Mar.
Morphology: Red Sea Fans are colonial organisms, with polyps that have 8-fold radial symmetry. Their eight tentacles are pinnate (having a feather-like appearance). The polyps have a flower-like appearance, a hollow digestive cavity, and specialized stinging structures in tentacles surrounding the mouth. As octocorals, they have tiny spine-like hard parts in their bodies called sclerites (or spicules) that give them some degree of support. The branches have a central core, which is made of a horn-like substance called gorgonin. Gorgonin is a protein which is exclusive to the gorgonians and which contains significant amounts of iodine and bromine. The sclerites are located in the solid core. The polyps are embedded in a gelatinous material (called the coenenchyme) which surrounds the core. The material surrounding the openings in the coenenchymes (from which the polyps emerge) are called calyces (singular calyx). The branches are arranged in a fan-shaped plane. They reach a maximum of 30 cm (11.7 inches) in height.
Colony Architecture: The Red Sea Fan typically forms a single, erect, flat fan that stretches horizontally, frequently resulting in colonies that are visibly wider than they are high. Mature forms occasionally sprout a small secondary accessory fan extending perpendicularly away from the primary plane.
Mesh and Branch Metrics: The Red Sea Fan has a fine, mathematically even reticulation grid averaging a dense 27 meshes per square centimeter. Individual meshes are predominantly small, square to polygonal windows measuring 1.0 to 2.5 mm across, supported by very slender branches that are up to 0.8 mm in diameter.
Surface Texture and Calyces: The Red Sea Fina completely lacks continuous vertical midribs, though brief thickened branches may cluster tightly right above the holdfast stem. The tissue surface is distinctly rough and heavily warty, characterized by crowded, protruding, and pointed calyces arranged in alternating biserial rows around the branch twigs.
Coloration Profiles: Live and dry colonies of Red Sea Fans display a range of deep colors, predominantly purple, dark violet-purple, and rich golden ochre. When expanded their active polyps are a stark, contrasting white.
Field Identification Key: The mesh of the Red Sea Fan has a slightly variable, wavy or fluid polygonal grid layout, and the branch surface are distinctly rough, bumpy, and warty to the touch.
Habitat and Distribution: Red Sea Fans are found attached to offshore reefs and rocks, subtidally, and to depths of 35 m (115 feet). They branches are usually oriented to be perpendicular to the prevailing current or surge, to facilitate filter feeding. Red Sea Fans are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean, including the Revillagigedos Islands.
Diet: An azooxanthellate (non-photosynthetic) suspension feeder. The tiny octocoral polyps rely entirely on localized current velocity to push micro-zooplankton (copepods and invertebrate larvae), microscopic phytoplankton, and drifting organic detritus (marine snow) directly into contact with their predatory tentacles. It lacks the mouth size and nematocyst strength to safely capture macro-plankton like fish eggs or whole fish larvae.
Predators: Specific study on targeted Red Sea Fan predation remains scarce. The fleshy coenenchyme layer is subject to opportunistic grazing and tissue scaling by specialized Panamic corallivores, including ovulid sea snails (gastropods), dedicated nudibranchs, and omnivorous browsing reef fish.
Reproduction: The species is gonochoric (separate sexes), operating with separate male or female colonies. Propagation occurs through synchronized broadcast spawning events triggered by lunar and seasonal markers. External fertilization in the water column generates a free-swimming planktonic planula larval stage before benthic settlement. Asexual growth allows the colony to heal structural lesions and extend its grid via continuous budding of the coenenchyme layer.
Ecosystem Interactions: The exceptionally dense, fine-meshed lattice structure acts as a vital structural microhabitat matrix. The warty, tightly-woven network behaves as an effective localized current break, providing high-stability shelter, nursery grounds, and secure attachment perches for complex micro-invertebrate communities, including brittle stars, caprellid amphipods, copepods, and juvenile reef fish.
Human Interactions: Direct human interaction is minimal, with no significant targeted commercial harvest. It faces passive structural threats from coastal eco-tourism, including recreational dive traffic, anchor damage, and entanglement with abandoned commercial gillnets.
Synonyms: Gorgonia (Litigorgia) adamsii, Gorgonia adamsii, Leptogorgia adamsii, and Litigorgia adamsii.