Fish-eating Anemone, Urticina piscivore

Fish-eating Anemone, Urticina piscivore. Underwater photographs taken in the coastal waters off Monterey, California, February 2022. Photographs and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny:  The Fish-eating Anemone, Urticina piscivora (Sebens & Laakso, 1978) is a member of the Actiniidae family of True Sea Anemones. The genus Urticina is one of fifty-six genera in this family, and there are fifteen species in this genus. They are also known as the Fish-eating Urticina and in Mexico as anémona pescadora. The name urticina is derived from the Latin word for the stinging nettle plant, based on this species’ ability to sting.

Morphology: Fish-eating Anemones are easily recognized by their large size and their smooth, deeply red to maroon, column. They have radial symmetry with tentacles located on the margin of the disk, giving them a flower-like appearance. They attach to hard surfaces with a pedal disk. They lack a calcareous skeleton, have a hollow digestive cavity, and specialized stinging structures in tentacles. The oral disk is yellowish. The tentacles may be pink or white. Juveniles are generally more brightly colored than adults.  Fish-eating Anemones are  large in stature having a maximum disk diameter of 34 cm (14 inches) and  the column can be 25 cm (10 inches) in height.

Habitat and Distribution: Fish-eating Anemones are found attached to rocks and other hard surfaces from the lower intertidal zone to depths up to 55 m (180 feet). They are solitary individuals that are often in areas exposed to the open coastline. In Mexican Waters the Fish-eating Anemone is a resident of the Pacific, but are limited to the entire West coast of the Baja Peninsula. They are  absent from the Gulf of California.

Diet:  Fish-eating Anemones are omnivorous, sessile, suspension feeders. They use their stinging tentacles to paralyze prey, which as their name suggests, includes small fish. They also consume suspended detritus, plankton and shrimp. They are an azooxanthellate species.

Predators:  Adult Fish-eating Anemones have no known predators. In their larval stage they are probably eaten by fish and other suspension feeders, but that has not been documented.

Reproduction:  Fish-eating Anemones are gonochoric ( male or female for life). They have the ability to reproduce asexually or sexually. Asexual reproduction can happen by longitudinal fission, latitudinal fission, or just by leaving a piece of the pedal disk behind when it moves. Sexual reproduction is accomplished through broadcast spawning, with external fertilization. The eggs hatch into planular larva, eventually settling to the bottom and metamorphosing into the adult form.

Ecosystem Interaction:  Fish-eating Anemones have a commensal relationship with the Painted Greenling, Oxylebius pictus. Juvenile Greenlings shelter among the tentacles at night.

Human Interaction:  Fish-eating Anemones have no direct impact on human activities. 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: Telia piscivora