Portuguese Man-of-war
(Physalia Physalis)
What everyone should know
By Doctor Erick M. Salado

Kingdom: Animalia
Phylum: Cnidaria (that possesses a filamentary urticating organ)
Class: Hydrozoa (invertebrates with poisonous polyps)
Order: Siphonophora Sub-order: Rhizophysalidae
Family: Physaliidae
Species: Physalia physalis

Physical Description

Known in Spanish as "Agua Mala (bad water)" or "Barquito Portuguese" (Little Portuguese Boat – due to its resemblance to old Portuguese war sailboats), or in English as "Jellyfish" or more commonly "Portuguese Man-of-War", when it actually is neither a boat, nor water, nor fish, nor jelly, nor Portuguese.

The Physalia is a hydrozoa of gelatinous appearance shaped like an Argon gas filled balloon. The animal is of a reddish or violet-hued translucent blue color, between 3 and 12 inches (9-30 cm) long, and it rises up to 6 inches (15 cm) above the surface of the water when it floats in the ocean. One end of its body is round and the other more slender, on the upper part it has a crest that reminds one of the sail of a boat and on the lower part a group of tentacles that may reach up to 165 feet (50 meters) in length when fully extended.

Colonies of Physalia are floating hydrozoa that consist of four types of polyps:

1. Pneumatophore, air bladder or float
2. Dactylozooides or tentacles that carry Nematocysts with venomous capsules
3. Gastrozooides or feeding zooide
4. Gonozooides which produce the reproductive gametes

The Urticating Cells or Nematocysts are located in the tentacles. These cells are the ones in charge of obtaining nutrients and they contain the toxin capsules. Their action is based on the hydrostatic and osmotic pressure of each individual cell. According to size Physalia have two types of nematocysts: small and large. A characteristic of these cells is that they conserve their power supply even after being detached from the main organism, and people walking on the shore's wet sand where these organisms have been washed up can be affected by them. The toxin secreted by the tentacles' capsules is 75% more powerful than the poison of a cobra.

The Pneumatophore or Floater is an elongated hypertrophied polyp full of gas shaped like a sealed bag with a crest resembling a sail. Some have an inclination to the left and others to the right.

Sensorial cells are the very numerous temperature and tactile receptors located on the epidermis of the tentacles and in the region surrounding the mouths.

Each individual is actually a colony of same-sexed organisms, feminine or masculine, with sex organs called gonozooides. Gonozooides are small sacks that contain the ovaries or testicles.

Geographical Distribution and Habitat

The Portuguese Man-of-war colonies live in saltwater tropical and sub-tropical seas and generally float on the surface of the warm waters of the Atlantic, Pacific and Indian Oceans, and of the Caribbean and Sargasso Seas. They are commonly found along the coasts of the Gulf of Mexico and its currents, as well as along the coasts of the Florida Keys.

Reproduction

Although it is not known for certain, fertilization of the Physalia is believed to occur near the surface in the open sea since gametes (reproductive cells) are released from gonozooides that open in water. This release might be triggered by some chemical reaction that takes place when the Portuguese Men-of-war gather in some place. A large group of individuals is probably needed to achieve fertilization. Reproduction occurs mainly in autumn, since many young Physalia can be seen near the beach in winter and spring. Larvae develop very quickly and become small floating shapes.

Behavior

Portuguese Men-of-war cannot swim, but they float with the help of their gas-filled bladders and drift due to the action of wind and currents. "Left-handed" Physalia move at an angle of 45 degrees right of the direction from which the wind blows and "right-handed" ones do the opposite. This distinction is crucial for the dissemination of these animals.

Feeding Habits

The Portuguese Man-of-war catches its food between its tentacles and feeds primarily on young and some small adult fish, occasionally on larger fish such as mackerel and flying fish. They also consume shrimp, crustaceans and other small plankton animals. Although 70-90% of their diet is fish.

Tentacles are used to capture prey and as a defense mechanism. Food is digested in the gastrozooides, which are like stomachs with individual bag-shaped mouths. There are multiple gastrozooides located beneath the float. Digestion occurs by secreting enzymes that disintegrate proteins, carbohydrates and fat. After the food has been digested, nutrients are absorbed towards the body and circulated to the animal's different polyps. The undigested wastes are expelled through the mouths.

Negative Economical Importance

Physalia affect tourists and tourism in areas where they are common. Due to their stings, each year a lot of money is spent in medical treatment for people affected in beaches and spas. People suffer an inflammatory reaction as a result of the histamine produced by the victims' cells when they have been in contact with the neurotoxins from the nematocysts.

Positive Economical Importance

The Portuguese Man-of-war serves as food for some fish and crustaceans (sand crabs) that can have commercial value.

Other considerations

A very important aspect of the Portuguese Man-of-war is its symbiotic relationship with various types of fish like the Clown Fish, which is known as the Portuguese Man-of-war's fish, or the young Yellow Jack. These fish live in between the tentacles and can rarely be seen elsewhere. The Clown Fish produces a slippery mucus that prevents stimulation of the nematocysts. There are many fish of the "Nomeus" genus that do not seem to have the protective mucus, and when they approach a Physalia they swim around it in all directions near the surface, following a circular pattern in order to avoid the dactilozooides and feed from the tentacles located near the float.

Symptoms produced by contact with Hydrozoa (Portuguese Man-of-war):

• Very painful, reddish, raised papules tracing lines that follow the area of contact with the tentacles and resemble whiplashes.

• Muscular spasms in the affected extremity or region.
• Papules can turn into vesicles or blisters and leave pigmented scars.
• With repeated exposure or extended contact, systemic reactions such as nausea, vomit, chills, fever, cephalea (headache), dizziness, vertigo, cardiac arrhythmia, faintness, weakness and muscular fasciculation may develop.
• Other symptoms such as excessive production of tears, rhinorrhea (running nose), painful breathing (pleuritic pain).
• In extreme cases (rare) of allergic reactions, anaphylactoid or anaphylactic symptoms such as dyspnea (lack of air) and glottis edema may occur.

Treatment of lesions by contact with Physalia (Portuguese Man-of-war).

Although, as mentioned earlier, acute respiratory symptoms are uncommon or rare, if the affected person presents respiratory manifestations such as difficulty breathing and/or alteration of consciousness, etc. ask for emergency help and/or prepare to administer cardio-respiratory resuscitation. The Atlantic species (Physalia physalis) is the most dangerous and there are some reported deaths.

1. First, withdraw any fragment of adhered tentacle on the skin to avoid the exposure to the venom. This must be done carefully and avoiding rubbing or scrubbing of the affected skin at all cost, because this increases exposure. Use some object or gloves to do it, do not use your unprotected hands, because you will be hurt as well.
2. Then irrigate and rinse the affected area with seawater to wash out the nematocysts that might remain. Do not use freshwater, for this activates the nematocysts, except when the eyes have been affected. The use of ice also reduces the symptoms after the nematocysts have been removed.
3. Hot seawater that comes out from cooling systems of engines, specially from outboard engines, can be very useful, because the neurotoxin's proteins that come from the nematocysts denaturalize with heat and the urticating effect diminishes.
4. Vinegar (5-10% acetic acid) deactivates the nematocysts and it can be applied by sprinkling on the skin without rubbing.
5. If the nematocysts remain adhered after applying the above methods:

• Powder the area with Sodium Bicarbonate (baking powder), wheat flour or cornstarch, and later carefully remove the nematocysts by scraping with the blunt edge of a knife or something similar that will not damage the skin.
• Or cove the affected area with shaving cream and later remove the nematocysts in the same manner.

1. Pain can be treated with topical anesthetics such as lidocaine or benzocaine which can be generally found in sunburn lotions.
2. Reddening, inflammation and persistent itching may be relieved with anti-histaminics such as the ones containing dimenhydramine (Benadryl®) and/or topical steroids such as hydrocortisone 0.5% in cream.
3. In case of persisting muscular spasms, seek medical attention in order to receive intravenous Calcium Gluconate.
4. Skin lesions may infect at a second stage with bacteria, especially if blisters or vesicles full of liquid are present. In such cases the use of antibiotics is necessary.

Note: There are popular reports that recommend the use of human urine, claiming an immediate effect. Nonetheless, a study published in Australia shows that urine stimulates the nematocysts' discharges. There is no scientific documentation that supports this method and we do not recommend it. Alcohol is also contraindicated because it aggravates the symptoms and irritates the skin.

Special thanks to:
Dr. Eric M. Salado