Brown Gorgonian, Muricea fruticosa
Brown Gorgonian, Muricea fruticosa. Underwater photographs taken in Zihuatanejo Bay, Guerrero, March 2018. Photographs courtesy of Ron Woheau, Zihuatanejo.
Brown Gorgonian, Muricea fruticosa. Underwater photograph taken in coastal waters of the greater Los Cabos area, Baja California Sur, May 2018. Photograph courtesy of Bob Hillis, Ivins, Utah.
Brown Gorgonian, Muricea fruticosa. Underwater photograph taken in coastal waters off Loreto, Baja California Sur, May 2023. Photographs courtesy of Dr. Tom Bartol, Carlsbad, California.
Brown Gorgonian, Muricea fruticosa. Underwater photograph taken in coastal waters off Loreto, Baja California Sur, October 2024. Photograph and identification courtesy of Bob Hillis, Ivins, Utah.
Brown Gorgonian, Muricea fruticosa. Octocoral courtesy of the commercial fishermen of Todos Santos, Baja California Sur, March 2013. Identification courtesy of Bob Hillis, Ivins, Utah.
Phylogeny: The Brown Gorgonian, Muricea fruticosa (Verrill, 1869), is an octocoral and a member of the Plexauridae Family of Gorgonians. The Muricea Genus is one of five genera in the Plexauridae Family and there are thirty-three species in the Muricea Genus. They are also known as the Bushy Gorgonian and Sea Fan. The species name fruticosa comes from the Latin adjective meaning “bushy” or “shrubby”. Muricea fruticosa typica is an accepted subspecies for this species and Muricea fruticosa var. miser is an accepted variety.
Morphology: The Brown Gorgonian is a colonial organism, that is composed of thousands of individual polyps. Gorgonians have flexible branches that often sway with the currents, unlike stony corals. The branches have a hollow axial core that does not contain sclerites and is composed of a horn-like material call gorgonin. Gorgonin is a protein which is exclusive to the gorgonians and which contains significant amounts of iodine and bromine. In Brown Gorgonians, the sclerites are embedded in the polyp tentacles and in the coenenchyme which surrounds the core. Brown Gorgonians have reddish-brown branches and white polyps that provide a thick bushy appearance when extended. The polyps have tentacles that are retractable. They reach a maximum of 90 cm (2 feet 11 inches) in height.
Habitat and Distribution: Brown Gorgonians are found attached to hard surfaces such as coral, pilings, rocks, kelp forests, and wreckage, in current-swept areas. They are often in shaded areas such as caves and overhangs. They live at depths between 6 m (20 feet) and 100 m (330 feet). Brown Gorgonians are a subtropical Eastern Pacific species that have a discontinuous range in Mexican waters of the Pacific Ocean being found from Punta Eugenia, Baja California, northward along the northwest coast of Baja and south of the Midriff Islands in the Sea of Cortez.
Diet: The Brown Gorgonian is a nocturnal sessile suspension feeder that captures drifting food in the water column by individual polyps with small tentacles. These nutrients will reach all members of the colony through channels in the gastrovascular cavity. The Brown Gorgonian’s diet consists of water-borne prey like plankton, larvae, and eggs. They are an azooxanthellate coral.
Predation: The Brown Gorgonian is preyed upon by the Leather Star, Dermasterias imbricatar, and snails.
Reproduction: Brown Gorgonians can reproduce asexually through budding and sexually through spawning. During spawning, mass amounts of eggs and sperm are released into the water and fuse into gametes. The larvae will eventually settle on a substrate and begin to form a polyp. From here, a colony grows through cloning (asexual reproduction).
Ecosystem Interactions: Brown Gorgonians produce chemicals that deter fouling caused by diatoms and other small organisms. They are thought to host microbial parasites such as mycoplasma, spirochaetes, and other bacteria. They also host the Sea Fan Crab, Quadrella nitida, in a commensal relationship.
Human Interactions: Brown Gorgonians have a very limited impact on human activities. They are extremely tolerant of water pollution and can thrive where other species would be displaced. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Thesea corosslandi and Pseudothesea crosslandi.