There have been a few calls and some social media buzz lately about the blue balloon-like structures washing up on the beaches. These are a colony organism called the Portuguese Man o’ War, named for the blue sails of ancient warships. This is not a single organism: it’s a siphonohore: a colony of organisms called polyps that work together (like corals do) to interact as one: helping each other eat, survive, move, and reproduce.
Sometimes these colony organisms are in large groups, being pushed by the wind in a large group, and we’ll find them washed up ashore in multiples. In my 19 years on this beach, I have only seen an influx of these siphonophores on about four occasions, so it’s not a regular occurence.
They really do look like balloons that have been partly deflated in the wrack line. Sometimes you can still see the inflated structures that keep the Pneumatophores (the topmost polyp, or the sail) afloat and at the water’s surface, and there is often a pinkish hue at the very top.
You’ll want to be careful: the tentacle polyps have nematocycts, or stinging cells that can paralyze their prey, and those tentacles (which average about 30 feet long) can be as long as 150 feet! If there are still nematocyst cells in the tentacles, they can pack a powerful wallop, stinging a beachcomber even weeks after they’ve washed ashore.
Not a Jellyfish
While the venomous nature of the man o’war often puts it in the same category of jellyfish, the man o’ war is not an actual jellyfish. It is a colony organism while jellyfish are single organisms. It has no way of locomotion, while jellyfish can contract and move through the water, and it’s usually found in tropical waters whereas the jellyfish are more ubiquitously spread around the oceans.
Not the only colony organism in town
We’ve found other colony organisms on our beach, made up of invertebrate polyps that work together for the good of the whole: sea whips and sea pansies.
Enjoy these weird creatures on the beach, and give them a wide berth until they float back out to sea!