Home news Portuguese man-of-war: The things you wanted to know.

Portuguese man-of-war: The things you wanted to know.


More Portuguese man-of-war have washed up on beaches along the coast of Cornwall and Wales in what experts say is the biggest stranding since 2012.Perranporth beach was closed after a large number of the creatures appeared.Their long purple tentacles can give a painful sting which in extremely rare cases can be fatal, said the Marine Conservation Society (MCS)Dr Peter Richardson from the society answered your questions about Portuguese man-of-war.Where does the name come from?The name comes from the shape of the sail which, when it is inflated, looks like an 18th century Portuguese battle ship, Mr Richardson said.

Is it true that vinegar will help the pain like jellyfish stings?”Jellyfish strings can be acid or alkali,” said Mr Richardson. “Vinegar is an acid so if you put it on an alkaline sting it will help the pain. If you put it on an acidic sting you’d make the pain worse. “As fortune would have it a man-of-war sting is alkaline. There’s been all sorts of debate but the most recent scientific research has come from National University of Ireland lecturer Dr Tom Doyle.”He concluded that the best way to treat a sting is to remove the tentacles with tweezers, then apply vinegar followed by warm water at about 45 degrees or as warm as the patient can bear.” He said lifeguards in Australia carry vinegar to treat stings.What makes the venom fatal?”The venom is a strong alkaline liquid which is unique to the man-of-war. It is used to paralyse small fish as its prey,” said Mr Richardson.”If someone has an allergic reaction it can cause fever, shock and affect the heart and lung functions, although this is extremely rare.”

How do they reproduce?A man of war is a siphonophore – a type of an animal that is made up of a colony of organisms working together.”They have sex organs called gonozooids which can be either male or female,” said Mr Richardson. “They release their sperm and eggs into the sea where they meet up and fertilise.”These create floating larvae which grows a colony of four polyps – the float, the sting, the reproductive cells and the digestive system.”What do they eat?”It’s thought the larvae feed on plankton and when they are fully developed they catch baby fish and small adult fish,” said Mr Richardson.”There are some small fish species which live among the tentacles and are covered in a mucus which protects them from the sting.”It is thought that the man-of-war provide shelter while the fish species that live among the tentacles attract large fish which become prey, he said.

Do they live on their own or in groups?”These are solitary animals. They don’t shoal or swarm.”The reason they get together is because they travel in the water whichever way the wind blows,” Mr Richardson said.
Source: Cornish BBC