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Portuguese Man-o-war (Physalia physalis) | Everything You Need to know

Blog » Wildlife » Portuguese Man-o-war (Physalia physalis) | Everything You Need to know

Every year, with the arrival of spring, the Azores see the appearance of many Portuguese Man-o-war (Physalia physalis). Although it is the most poisonous species you can find in the archipelago, don’t worry. On our whale and dolphin watching trips, you will be in complete safety. Sometimes people confuse the Portuguese Man-o-war with jellyfish (which we call “água viva” in the Azores). But the only thing they have in common is the fact that they have long tentacles. Let’s see then what are the main characteristics of the Man-o-war.

What characterizes the Portuguese Man-o-war?

Contrary to what many think, the Man-o-war is not a single organism. It is rather composed of a set of 4 types of organisms that work together to ensure their survival. We call these organisms polyps or zooids. The Portuguese Man-o-war (Physalia physalis) can be classified as a colony of organisms that, although different, share the same DNA among themselves.

Roxane Rambert | A Portuguese Man-o-war around Pico island
Roxane Rambert | A Portuguese Man-o-war around Pico island

This species is invertebrate and carnivorous. Each of these four types of polyps are unique in the Portuguese Man-o-war and each has specific functions.

Pneumatophore (sailing- navigation)

Man-o-wars, unlike jellyfish, can’t swim. Therefore one of the polyps is responsible for filling with gas, forming a kind of vesicles on the surface that functions as a sail. This vesicle can reach 30cm in length and 15cm in height.

Since the Man-o-war doesn’t swim and is only transported by wind and currents, they can often be found along the coast (beaches for instance).

So be careful… When you see something on the beach with pink, purple and an intense blue with a mirrored glow or a gelatinous appearance, do not touch it!

Mariana Silva | A Portuguese Man-o-war on a beach on the island of São Miguel
Mariana Silva | A Portuguese Man-o-war on a beach on the island of São Miguel

Dactylozoids (capture of prey)

Man-o-wars sail with the current and depend on the power of attraction to feed. They catch small fish and organisms approaching their tentacles. It is through the poison in these tentacles that they can immobilize and kill their prey. These tentacles are dark blue, curled and can expand and reach up to 50 meters in length!

Gastrozoids (digestion)

The digestive system of the Man-o-war is transparent and it is possible to observe this polyp in action to digest its meals. The nutrients are then distributed with the remaining polyps.

Gonozoids (reproduction)

Each individual organism of the Man-o-war, that is, each polyp, is unisexual with a gonozoid (organ responsible for reproduction) and may contain ovaries or testicles. And did you know that all the organisms of the same Man-o-war are of the same sex? It is amazing the organization and complexity of a Portuguese Man-o-war. When ready for reproduction the eggs/sperm are released into the environment. This is an attempt to fertilize the eggs and generate small larvae of the different polyps that form a Man-o-war.

Roxane Rambert | We spot Man-o-wars frequently during our whale and dolphin watching tours
Roxane Rambert | We spot Man-o-wars frequently during our whale and dolphin watching tours

Why is it called Portuguese Man-o-war?

The pneumatophore (body responsible for navigation) resembles the sail present in Portuguese warships of the 19th century. XV and XVI: the Caravel. As this species is very common in Portugal, the British named it Portuguese man o’ war (caravel), like the ship. In fact, in several languages this species is known by the combination of the word Portugal and the name of the caravel ship. For example, Carabela, Caravella, Galère, Galeere, Oorlogschip, Orlogsmand, Örlogsman, Gálya.

What should you do if you are stung by a Portuguese Man-o-war?

In case of being stung by a Portuguese Man-o-war it is recommended to wash the wound with salt water and put vinegar. The purpose of vinegar is to help stop the discharge of poison to the body of the affected person.

Mariana Silva | Two Man-o-wars on the beach, a frequent phenomenon in spring
Mariana Silva | Two Man-o-wars on the beach, a frequent phenomenon in spring

What should you not do?

Under no circumstances should alcohol or freshwater be put in nor press the affected area with a compress. This speeds up the process of passing the poison into the bloodstream.

Could it be dangerous?

In case the person stung has allergies, it is necessary to take extra care and pay attention to any sign of an allergic reaction.

If the pain doesn’t go away or if you see the slightest sign of an allergic reaction, go to the nearest health center. Although Man-o-wars have a very powerful and painful poison, it is rare for this to be lethal to humans.

Man-o-wars sting can cause burns to the third degree as well as some of the following symptoms:

  • Intense and instantaneous pain;
  • Gastrointestinal symptoms (abdominal pain, nausea and vomiting);
  • Muscle spasms;
  • Headache;
  • Drowsiness;
  • Fainting;
  • Cardiorespiratory disorders.

If there are some dead on the beach… Can I touch it?

Laura Gonzalez | A Man-o-war floating on the surface of the sea
Laura Gonzalez | A Man-o-war floating on the surface of the sea

Portuguese Man-o-wars are dangerous and even after dead they can sting and transmit their poison. It is therefore necessary to respect the alerts in bathing areas and have increased attention when it is the period for Man-o-wars, thus avoiding getting stung by one. Here’s an experience we don’t recommend to anyone! When swimming, always be careful, as sometimes it is possible to confuse a Man-o-war with a floating bag.

Do Man-o-wars have natural predators?

Some species see the Portuguese Man-o-war as food. One of these species is often observed in the Azores: the loggerhead turtle that by having the hard skin becomes immune to the toxin present in the tentacles of the Portuguese Man-o-war. Another species that also feeds on Man-o-wars is the sunfish.

Rui Rodrigues | A beautiful photo of a Man-o-war with its body visible underwater
Rui Rodrigues | A beautiful photo of a Man-o-war with its body visible underwater

Where can you find the Portuguese Man-o-war?

It is common to find Portuguese Man-o-wars in subtropical and tropical temperate waters. However, as this species follows the currents, it has already been found in the Pacific Ocean, Indian Ocean, Caribbean Sea, Sargasso Sea, beyond the Atlantic Ocean.

TOUR RELACIONADO 
Observe baleias e golfinhos além de outras criaturas do mar como caravelas portuguesas | Reserve agora!

They’re very beautiful and colorful, but… for a scare-free holiday, always be alert, especially in spring and early summer when swimming in the ocean.

Mariana Silva