Portuguese Man o' War

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Portuguese Man o' War
Scientific classification
Kingdom: Animalia Phylum: Cnidaria Class: Hydrozoa Order: Siphonophora Family: Physaliidae Genus: Physalia Species: P. physalis
Binomial name
Physalia physalis (Linnaeus, 1758)

The Portuguese Man o' War (Physalia physalis), also known as the blue bubble, blue bottle, man-of-war, or the Portuguese man of war, is a jelly-like, marine invertebrate of the family Physaliidae, order Siphonophora, class Hydrozoa, and phylum Cnidaria.

The common name comes from a Portuguese war ship type of the 15th and 16th century, the man-of-war (named caravela-portuguesa in Portuguese, caravel), which had triangular sails similar in outline to the bladder of the Portuguese Man O' War.

They are commonly but erroneously thought of and referred to as a jellyfish. In fact, a Portuguese Man O' War is not a single animal, but rather a siphonophore – a colony of four kinds of minute, highly modified individuals, which are specialized polyps and medusoids.^[1] Each such zooid in these pelagic colonial hydroids or hydrozoans has a high degree of specialization and, although structurally similar to other solitary animals, are all attached to each other and physiologically integrated rather than living independently. Such zooids are specialised to such an extent that they lack the structures associated with other functions and are therefore dependent for survival on the others to do what the particular zooid cannot do by itself.

A similar group of animals are the chondrophores, which are specialised hydroids that float at the surface of the open ocean.

The Portuguese Man O' War is infamous for swarming in groups of thousands and for a very painful, powerful sting.

Contents 1 Habitat and location 2 Structure 3 Venom 4 Predators 5 Commensalism/Symbioses 6 Etymology 7 See also 8 References 9 External links 10 Gallery

[edit] Habitat and location

The Portuguese Man O' War lives at the surface of the ocean, with its float above the water, serving as a sail, and the rest of the organism hanging below the surface. It has no means of propulsion, but is moved by a combination of winds, currents, and tides. It is found in open ocean in all of the world's warm water seas but most commonly in the tropical and subtropical regions of the Pacific and Indian oceans, and the northern Atlantic Gulf Stream. Strong onshore winds may drive them into bays or on beaches.

Physalia physalis is the only widely distributed species. P. utriculus, commonly known as the bluebottle, frequently occurs in the Pacific and Indian oceans.

They are reported abundantly off the Karachi coast in Pakistan, and are common in the ocean off parts of Australia and New Zealand especially at the Sand's Pit and Hawkes Bay beaches during the months of June and July. They come ashore all along the northern Gulf of Mexico and both east and west coasts of Florida as well around the Hawaiian Islands. They are also frequently to be found along the east coast of South Africa, especially on the KwaZulu-Natal beaches (particularly if the wind has been blowing steadily on shore for a number of hours). The Portuguese Man O’War has also been spotted in the Mediterranean sea, after first being spotted off the coast of Spain, later in Corsica.^{[citation needed]}

It is rare that only a single Portuguese Man O' War is found; the discovery of one usually indicates the presence of many as they can "swarm" in groups of thousands.

Attitudes to the presence of the Portuguese Man O' War vary around the world. Given their sting, they must be treated with caution and the discovery of a number of blue bottles washed up on the beach might lead to the closure of a whole beach.^[2]

[edit] Structure

The Portuguese Man O' War has an air bladder (known as the pneumatophore or sail) that allows it to float on the surface of the ocean. This sail is translucent and tinged blue, purple or mauve. The sail may be 9 to 30 centimetres long and may extend as much as 15 centimetres above the water. The Portuguese Man O' War secretes gas into its sail that is approximately the same in composition as the atmosphere, but may build up a high concentration of carbon dioxide (up to 90%). The sail must stay wet to ensure survival and every so often the Portuguese Man O' War may roll slightly to wet the surface of the sail. To escape a surface attack, the sail can be deflated allowing the Man O' War to briefly submerge .^[3]

Below the main body dangle long tentacles, which occasionally reach 50 meters (165 ft)^[4] in length below the surface, although ten metres (thirty feet) is the average. The long tentacles "fish" continuously through the water and each tentacle bears stinging venom-filled nematocysts (coiled thread-like structures) which sting and kill small sea creatures such as small fish and shrimp. Contractile cells in each tentacle work to drag prey into range of the digestive polyps, the gastrozooids, another type of polyp that surrounds and digest the food by secreting a full range of enzymes that variously break down proteins, carbohydrates and fats. Gonozooids are responsible for reproduction.

Certain small fish are able to live among the tentacles (being nearly immune to the poison from the stinging cells) and have a commensal symbiotic relationship, i.e. a relationship beneficial for the symbiont, with no negative or pathogenic effect on the host.

The Portuguese Man O' War's float is bilaterally symmetrical with the tentacles at one end, whereas by contrast the chondrophores are radially symmetrical with the sail at an angle or in the center. Also, the Portuguese Man O' War has a siphon, while the chondrophores do not.

[edit] Venom

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The stinging venom-filled nematocysts in the tentacles of the Portuguese Man O' War can paralyze small fish and other prey. Detached tentacles and dead specimens (including those which wash up on shore) can sting just as painfully as the live creature in the water, and may remain potent for hours or even days after the death of the creature or the detachment of the tentacle.

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin which normally last about 2–3 days after the initial sting, the pain should subside after about 1 hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, more intense pain. A sting may lead to an allergic reaction. There can also be serious effects, including fever, shock, and interference with heart and lung action. There have even been deaths, although this is rare. Medical attention may be necessary, especially where pain persists or is intense, or there is an extreme reaction, or the rash worsens, or a feeling of overall illness develops, or a red streak develops between swollen lymph nodes and the sting, or if either area becomes red, warm and tender.

Research suggests that in the normal course the best treatment for a Portuguese Man O' War sting is:

(a) to avoid any further contact with the Portuguese Man O' War and to carefully remove any remnants of the creature from the skin using an object(taking care not to touch them directly with fingers or any other part of the skin to avoid secondary stinging); then

(b) to apply salt water to the affected area (not fresh water, which tends to make the affected area worse);^[5]

If eyes have been affected they should be irrigated with copious amounts of room temperature tap water for at least 15 minutes and if vision blurs, or the eyes continue to tear, hurt, swell, or are light sensitive after irrigating, or there is any concern, a doctor should be seen as soon as possible;

(c) to follow up with the application of hot water (45°C/113°F) to the affected area, which eases the pain of a sting by denaturing the toxins;^[6] and finally,

(d) to apply ice, preferably in the form of an icepack as this should be effective at suppressing any swelling and pain through reducing the activity of the toxins and reducing the sensation, and therefore pain, of the area of skin around the ice. Additionally, ice constricts blood vessels, reducing the speed at which the venom travels to other parts of the body.

Vinegar dousing has been shown to cause discharge of nematocysts from the larger (P. physalis) man-of-war species (that is, increasing the toxin and worsening the symptoms) while the effect of vinegar on the nematocysts of the smaller species (which has less severe stings) has been mixed.

The Portuguese Man O' War is often confused with jellyfish by its victims, which may lead to improper treatment of stings, as the venom differs from that of true jellyfish.

[edit] Predators

The Loggerhead Turtle feeds on the Portuguese Man O' War; indeed it is a common part of its diet.^[7] The skin of the turtle is too thick for the Portuguese Man O' War sting to penetrate and launch its venom.

The sea slug Glaucus atlanticus also feeds on the Portuguese Man O' War,^[8] as does the violet snail Janthina janthina.^[9]

Blanket octopuses are immune to the venom of the Portuguese Man O' War, and the female has been known to rip off its tentacles and use them for defensive purposes^[10]

[edit] Commensalism/Symbioses

The Portuguese Man o' War is often found with a variety of marine fish, including shepherd fish, clown fish and yellow jack, species that are rarely found elsewhere. The clown fish can swim among the tentacles with impunity, possibly due to its mucus that does not trigger the nematocysts. The shepherd fish seems to avoid the larger, stinging tentacles, but feeds on the smaller tentacles beneath the gas bladder. These fish benefit from the shelter from predators provided by the stinging tentacles, and for the Portuguese Man o' War the presence of these species may attract other fish to feed on.^[11]

[edit] Etymology

The Portuguese Man O' War (named caravela-portuguesa in Portuguese) is named for its air bladder, which looks similar to the triangular sails of the Portuguese ship (man-of-war) Caravela latina (two- or three-masted lateen-rigged ship caravel), of the 15th and 16th centuries.

[edit] See also

• Portuguese man-of-war dermatitis

[edit] References

[edit] External links

Wikispecies has information related to: Physalia physalis

Wikimedia Commons has media related to: Physalia physalis

• Siphonophores.org - General information on siphonophores, including the Portuguese man-of-war
• Poisonous Animals: Blue bottle, Portuguese man-of-war
• National Geographic: Portuguese Man-of-War

[edit] Gallery

This section looks like an image gallery. Wikipedia policy discourages galleries of random images of the article subject; please edit the section in accordance with the policy, moving freely licensed images to Wikimedia Commons if they are not already hosted there.

Portuguese Man O'War Gulf Shores Alabama May 2008	Portuguese Man O' War, March 2008 Miami Beach, Florida	Portuguese Man O'War on Delray Beach, Florida	Portuguese Man O' War washed ashore at Batemans Bay, New South Wales, Australia; only the air bladder is readily visible
Portuguese Man O' War on Wollongong Beach.	Portuguese Man O' War washed ashore on Surfer's Paradise, on the Gold Coast in Australia	Portuguese Man O' War found at Biscayne National Park, Florida	Portuguese Man O' War washed ashore in Melbourne, Florida
Portuguese Man O'War captured live in Mayaro Beach, Trinidad and Tobago	Physalia physalis on the shore in Karachi, Pakistan	Portuguese Man O' War washed ashore in Palm Beach, Florida	'Blue Bottle Jellyfish' at Tawharanui Open Sanctuary, New Zealand
Portuguese Man O' War washed ashore on Horseshoe Bay Beach, Bermuda