Portuguese Man-of-war, Physalia physalia
Portuguese Man-of-war, Physalia physalia. Two collections off different beaches in the greater Los Cabos area, Baja California Sur, May 2018. Size: ca. 7.5 cm (3.0 inches). Capable of inflicting incredible pain in the collector.
Portuguese Man-of-war, Physalia physalia. Found along the shoreline at Bahía Santa Rosalillita, Baja California, September 2015. Catch and photograph courtesy of Barry Mastro, Escondido, California.
Phylogeny: The Portuguese Man-of-war Physalia physalis (Linnaeus, 1758), is a member of the Physaliidae family of Hydrazoans. The genus Physalia is the only genus in this family, and this is the only species in this genus. The Portuguese Man-of-war is also known as the Blue Bottle and the Portuguese Man O’War and in Mexico as Aguamala and Frigata Portuguesa.
Morphology: Portuguese Man-of-wars are free-floating, pelagic, hydrozoans. Man-of- wars appear to be a single organism but they are colony of four types of multi-cellular, interdependent, animals (zooids). Man-of-wars consist of an oval shaped, gas-filled, bladder that provides buoyancy, and long tentacles. The bladder has a sail-like structure on top to catch the wind. The sail may be right or left handed, which determines which direction they blow in the wind. The tentacles are muscular and contractile, and can reach up to 50 m (165 feet) in length. The tentacles are equipped with nematocysts (or cnidocysts) that deliver a toxic sting in order to capture prey or repel predators. The bladder can reach up to 30 cm (12 inches) in length. The bladder and tentacles are translucent blue to violet. For this reason, they are sometimes called “Blue Bottles”.
Habitat and Distribution: Portuguese Man-of-war are primarily found on the surface of the open ocean, though they are sometimes pushed into bays and harbors. Man-of Wars are unable to swim or dive and are at the mercy of the wind. Sometimes large groups of them are pushed ashore by the wind. Once ashore, they begin to die, though the nematocysts can remain active for days, or even weeks, after stranding. Man-of-wars are circumtropical in distribution. Specimens found in the tropical Atlantic are much larger than those found in the Pacific Ocean. For Portuguese Man-of-wars found along the Pacific coast of Mexico the bladder reaches only 5.1 cm (2.0 inches) to 8.0 cm (3.1 inches) in length, and the tentacle seldom exceeds 1 meter (3 feet 3 inches) in length. They also seem to be less venomous, though serious envenomation may still require advanced medical treatment. This size difference has led to some scientists classifying the smaller specimens as a distinct species, the Bluebottle, Physalia utriculus. The World Register of Marine Species (WoRMS) shows this as an unaccepted synonym. In Mexican waters Portuguese Man-of-war is found along the entire east coast and most of the west coast, including the entire Gulf of California. They are absent from the west coast of the Baja Peninsula north of Bahia Asunción, Baja California Sur.
Diet: Portuguese Man-of-war feed on fish and plankton. Once the tentacles sting their prey, the tentacles retract to pull the prey toward specialized digestive cells.
Predators: Portuguese Man-of-war are preyed upon by Ocean Sunfish, Mola mola, Loggerhead Sea Turtles, Caretta caretta, nudibranchs of the Genus Glaucus, and the Violet Sea Snail Shell, Janthina janthina.
Reproduction: Each individual Portuguese Man-of-war colony is gonochoric (male or female for life). Reproduction is sexual, via broadcast spawning with external fertilization. The fertilized eggs develop into larvae which then reproduce asexually by budding to form a new colony. Reproduction seems to occur primarily in the Fall.
Ecosystem Interactions: Several fish species, including Pilotfish, Naucrates ductor, Yellow Jack, Carangoides bartholomaei, Spotted Ruff, Mupus maculatus, Longspine Snipefish, Macroramphosus scolopax, and the Man-of-war Fish, Nomeus gronovii, carry on a commensal relationship with the Portuguese Man-of war. These fish gain protection by staying near the stinging tentacles in exchange to attract prey for the Man-of war.
Human Interactions: The nematocysts from a Portuguese Man-of-war can deliver excruciatingly painful stings to humans, and on rare occasions, may be fatal. Usually fatalities require that a large amount of tentacle come into contact with a large surface area of skin, especially on the torso. Small children are most susceptible. Generally, the stings appear as welts. Not all of the nematocysts fire their venom on first contact. Care should be exercised to avoid activating these remaining nematocysts. Do not flush the area with fresh water or alcohol as these have been shown to cause additional nematocysts to fire. Instead, use vinegar to flush the area, leaving it in contact with the tentacles for at least 30 seconds. If vinegar is not available, flush the area with seawater to remove the tentacles. Immerse the affected area in hot seawater for twenty to thirty minutes to further breakdown the venom and relieve pain.
From a conservation perspective the Portuguese Man-of-war has not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Arethusa caravella, Holothuria physalis, Holothuria velificans, Medusa utriculus, Physalia australis, Physalia gigantea, Physalia glauca, Physalia megalista, Physalia pelagica, Physalia pelasgica, Physalia utriculus, Physalis afer, Physalis arethusa, Physalis cornuta, Physalis elongata, Physalis glauca, Physalis lamartinieri, Physalis megalista, Physalis osbeckii, Physalis pelagica, Physalis tuberculosa, and Physsophora physalis.