Do you know Portuguese Man-Of-War (Physalia physalis)?

Portuguese Man-Of-War in the Azores

In springtime, our ocean is invaded by Portuguese Man-Of-War (Physalia physalis), but don’t worry we are not at war. Even if the Portuguese Man-Of-War is our most venomous species, we are safe watching them from our boats. People usually confuse them with jellyfish but the only thing they have in common is the fact that they have long tentacles. Let’s now see what are the characteristics of a Portuguese Man-Of-war.

What characterizes this species?

Unlike what many think, the Portuguese Man-Of-War is not a single organism. Instead, it is composed by a colony of 4 types of organisms that work together to ensure its survival. They are called polyps or zooids. It can be classified as a colony of organisms that, although different, share the same DNA with each other.

This species is invertebrate and carnivorous. Each of these four types of polyps is unique in Portuguese Man-Of-War and each has specific functions. They are divided as follows:

1. Pneumatophore (navigation)

Portuguese Man-of-War, unlike jellyfish, cannot swim. For this reason, one of the polyps is responsible for filling with gas, forming a kind of bladder on the surface that works like a sail and can reach 30cm in length and 15cm in height.

Since Man-of-War doesn’t swim, it is only transported by wind and currents, they can often be found along the coast, like beaches. So be careful… when you see something on the beach with pink, violet and intense blue color and a mirrored shine or a gelatinous aspect, don’t touch it!

2. Dactylozooid (prey capture)

As this species is not swimming actively just drifting by wind and currents, the Portuguese Man-Of-War depends on this polyp type. The tentacles are their weapons to kill small fish and small crustaceans. The tentacles are dark blue mostly curled but apparently able to expand up to 50 m in length. For humans, the venom is rarely lethal but very painful. Even after the creatures are dead, the poison is still harmful.

3. Gastrozooids (digestive)

The third polyp type is the digestive system which is, by the way, transparent so it is possible to see what they are eating. From here, nutrients are distributed to other polyps.

4. Gonozooid (reproduction)

Did you know that all organisms in the same Portuguese Man-Of-War are of the same sex? The complexity of this species is incredible. Each individual organism, or polyp, is unisexual, equipped with a gonozoid (the organ responsible for reproduction) and may contain ovaries or testicles. 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 this beautiful creature.

Why did they call it Portuguese Man-of-war?

The pneumatophore (the organism responsible for navigation) is similar to the sail in Portuguese warships of the 15th and 16th centuries. The expression Man-Of-War comes from the British Royal Navy but the boat type was developed in Portugal in the early 15th century. Also, the animal was first found in Portuguese waters so the English name of the species Physalia physalis is Portuguese Man-O-War. In other languages, it’s mainly the literal translation, a combination of the word Portuguese and the name of the warship (Caravela, Carabela, Caravella, Galère, Galeere, Oorlogschip, Orlogsmand, Örlogsman, Gálya …).


What you should do if you are stung by a Portuguese Man-of-War

If you are stung by a Portuguese Man-Of-War, it is recommended to wash the wound with salt water, add vinegar or urine to the affected area.

The purpose of vinegar is to help stop the discharge of poison into the affected person’s body. Under no circumstances should alcohol, freshwater, or pressure be applied to the affected area, as this speeds up the process of passing the poison into the bloodstream.

If the person has allergies, extra care and attention to any signs of an allergic reaction are necessary. If the pain does not go away or you see the slightest sign of an allergic reaction, go to the nearest health center. Although Man-Of-War have a very powerful and painful poison, it is rare to be lethal for humans.

Portuguese Man-Of-War sting can cause burns up to a third-degree, as well as some of the following symptoms:

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

Portuguese Man-Of-War are dangerous. Even after they are dead they can sting and transmit their poison. That is why it is necessary to respect the warnings in the bathing areas and to pay extra attention when it is their season, thus avoiding being stung by one. Here is an experience that we do not recommend to anyone! When swimming, always be careful, as it is sometimes possible to mistake one with a floating bag.

Some species see the Portuguese Man-Of-War as food. One of these species is frequently observed in the Azores: the loggerhead turtle which, due to its hard skin, becomes immune to the toxin present in the tentacles of the Portuguese Man-Of-War. Another species that also feeds on Man-Of-War is the sunfish.

Where can you find Portuguese Man-of-War?

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

Always be alert, especially in the spring and early summer when you are in the ocean.

Portuguese Man-Of-War and a fish in the Azores

Written by Carine Zimmermann 

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