We've all heard about it and we've all seen the portuguese man o’war (Figure 1), both in the water and on the beach.
But what exactly is the portuguese man o’war?
It looks like a jellyfish, but belongs to a completely different group of animals – the siphonophores – but while jellyfish is a single individual, siphonophores are a colony.
The individuals in the colony are called zooids and, like a colony of ants where each one has a function, in siphonophores, zooids are also specialized in “locomotion”, others in digestion, others in hunting and others in reproduction.
Everyone has to work together for the colony to thrive and no zooid can survive alone.
Most species of siphonophores live in deep water, but in the case of the Portuguese man o’ war this species lives on the surface, going to deeper waters to look for food or protection.
Physalia physalis , is the scientific name of the Portuguese man o’ war and this colony is formed by four types of zooids:
- Pneumatophore – creates the “balloon” that can be seen on the surface of the water and that has the ability to inflate or leak, depending on the weather conditions or the demand for food. It can reach 9 or 30 centimeters in size;
- Dactiozooids – form the tentacles, which can be between 20 and 50 meters long. They are the hunting device, as they contain numerous microscopic “harpoons” from which the venom comes out to immobilize the prey (small fish);
- Gastrozooids – digest food; - Gonozoids – responsible for reproduction.
This species prefers warm waters and can be found in the Azores, Madeira, Pacific and Indian Oceans.
They got their name because they remind us of the old ships / caravels that were sailing through the ocean at the time of the discoveries.
Unlike jellyfish that can swim, they can have their own locomotion, Portuguese man o’war depend on the wind and currents to move. The “balloon” that can be seen out of the water is the only mechanism that allows this species to move in the water, due to external actions (wind and current).
Its venom causes very strong pain, burns that can be of the third degree and if a very serious allergic reaction develops, we can suffer from arrhythmias and tissue necrosis (death).
Even when they are not sand, care must be taken because the poison can remain active. In case of contact, here is what you should do after washing and cleaning the affected area with sea water:
- Apply hot compresses (40º C) for about 20 minutes or,
- Apply undiluted vinegar
- • If you are in shock, have difficulty breathing or the pain persists, consult your doctor or pharmacist
Other specie very similar to the portuguese man o’war and also can be seen in Portugal main land and in the islands, is the Velella velella, de nome comum veleiro, é um pouco menos perigosa que a caravela portuguesa (Figura 3).
If you are interested in knowing more gelatinous organisms, visit the GelAvista program website: https://gelavista.ipma.pt/especies/
