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Portuguese man o' war

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This article is about the marine invertebrate. For other uses, see Man O' War.

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.

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

While the Portuguese Man O' War resembles a jellyfish, it is in fact 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 specialized 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 having a painful sting, and for swarming in many hundreds.

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 found in tropical Atlantic waters and occasionally as far north as the Bay of Fundy and the Hebrides, Mediterranean Sea.[2] P. utriculus (La Martiniere), commonly known as the bluebottle, occurs in the Pacific and Indian oceans.

They are reported abundantly off the Karachi coast in Pakistan, and are also common in the ocean off parts of Australia and New Zealand, particularly at the Sandspit and Hawkes Bay beaches during the months of June, July, and August. They are known to come ashore all along the northern Gulf of Mexico and both east and west coasts of Florida as well as 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.[3] [4]
In the summer of 2009, Pembrokeshire County Council warned bathers in its waters that the organisms had been sighted in Welsh waters.

There is also an abundance of Portuguese Men O' War in the waters of Costa Rica. Congregations of them can be found in the March and April months.

It is rare for only a single Portuguese Man O' War to be found; the discovery of one usually indicates the presence of many as they are usually congregated by currents and winds into groups of thousands.

Attitudes to the presence of the Portuguese Man O' War vary around the world. Given their sting however, they must always 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.[5]

Structure

The Portuguese Man O' War has an air bladder (known as the marissa 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 .[6]

Below the main body dangle long tentacles, which occasionally reach 50 metres (165 ft)[7] in length below the surface, although 10 metres (30 ft) is the average.[8] 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.

Venom

The Portuguese Man o' War is responsible for up to 10,000 stings in Australia each summer, particularly on the east coast, with some others occurring off the coast states of South Australia and Western Australia.[9]

The stinging venom-filled nematocysts[10] 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.[11]

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, although 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, a 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. Stings may also cause death,[12] 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 (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);[13][14]

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,[15] which eases the pain of a sting by denaturing the toxins.[16]

Vinegar dousing has been shown to cause strengthening 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 confirmed that will provoke hemorrhaging.[17] Vinegar is therefore not recommended.[14]

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.

Predators

The Loggerhead Turtle feeds on the Portuguese Man O' War; indeed it is a common part of its diet.[18] 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,[19] as does the violet snail Janthina janthina.[20]

Blanket octopi are immune to the venom of the Portuguese Man O' War, and they have been known to rip off its tentacles and use them for defensive purposes[21]

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.[22]

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.

See also

References

  1. ^ Grzimek, B., N. Schlager & D. Olendorf 2003. Grzimek's Animal Life Encyclopaedia. Thomson Gale.
  2. ^ Halstead,B.W., Poisonous and Venomous Marine Animals of the World, 1988, Darwin Press
  3. ^ article in El Mundo issue 07/05/2009
  4. ^ article in Ultima Hora issue: 3782 09/05/2009
  5. ^ "UK | England | Dangerous jellyfish wash up". BBC News. 2008-08-18. Retrieved 2009-12-07.
  6. ^ Physalia physalis. "Portuguese Man-of-War Printable Page from National Geographic Animals". Animals.nationalgeographic.com. Retrieved 2009-12-07.
  7. ^ Portuguese Man-Of-War Key Biscayne, Florida
  8. ^ Portuguese Man-of-War. National Geographic.
  9. ^ Fenner, Peter J. (1996). "Worldwide deaths and severe envenomation from jellyfish stings". Medical Journal of Australia. 165 (11–12): 658–61. ISSN 0025-729X. Retrieved 2009-09-04. In Australia, particularly on the east coast, up to 10 000 stings occur each summer from the bluebottle (Physalia spp.) alone, with others also from the "hair jellyfish" (Cyanea) and "blubber" (Catostylus). More bluebottle stings occur in South Australia and Western Australia, as well as stings from a single-tentacled box jellyfish, the "jimble" (Carybdea rastoni) {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  10. ^ 5. Yanagihara, A.A., Kuroiwa, J.M.Y., Oliver, L., and Kunkel, D.D. The ultrastructure of nematocysts from the fishing tentacle of the Hawaiian bluebottle, Physalia utriculus (Cnidaria, Hydrozoa, Siphonophora). Hydrobiologia 489, 139-150, 2002.
  11. ^ Auerbach, PS. (1997). "Envenomation from jellyfish and related species". J Emerg Nurs. 23: 555–65.
  12. ^ Stein MR, Marraccini JV, Rothschild NE, Burnett JW. (1989). "Fatal Portuguese man-o'-war (Physalia physalis) envenomation". Ann Emerg Med. 18 (3): 312–5. PMID 2564268.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ specialist from the University of Southampton appearing on BBC Breakfast program, date: 8am, Tue 19 August 2008.
  14. ^ a b Slaughter RJ, Beasley DM, Lambie BS, Schep LJ (2009). "New Zealand's venomous creatures". N. Z. Med. J. 122 (1290): 83–97. PMID 19319171.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ^ 3. Yoshimoto, C.M., and Yanagihara, A.A. Cnidarian (coelenterate) envenomations in Hawai’i improve following heat application. Transactions of the Royal Society for Tropical Medicine and Hygiene 96, 300-303, 2002.
  16. ^ Loten C, Stokes B, Worsley D, Seymour J, Jiang S, Isbistergk G (2006). "A randomised controlled trial of hot water (45 °C) immersion versus ice packs for pain relief in bluebottle stings". Med J Aust. 184 (7): 329–33. PMID 16584366.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ^ Exton DR (1988). "Treatment of Physalia physalis envenomation". Med J Aust. 149 (1): 54. PMID 2898725.
  18. ^ Brodie: Venomous Animals, Western Publishing Company 1989
  19. ^ By Carla Scocchi and Dr. James B. Wood site. "''Glaucus atlanticus'', Blue Ocean Slug". Thecephalopodpage.org. Retrieved 2009-12-07.
  20. ^ Morrison, Sue (1999). Wonders of Western Waters: The Marine Life of South-Western Australia. CALM. p. 68. ISBN 0730968944. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  21. ^ "Tremoctopus". Tolweb.org. Retrieved 2009-12-07.
  22. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
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