Ocean Baggies

Apart from windswept sand with a scattering of birds, and cold blue Atlantic with its beard of white ruffles, the eye finds no small focus on a December beach. Scale is grand and stretches in long diminishing perspectives with barely any interruption. Once the hour advances past mid-morning and the tide subsides, there is little to suggest that the beach is other than a flat sandy highway running empty in both directions. But natural settings are never quite that empty, and somewhere along this bounding space the line of sight is broken by an appearance of fish, bird or object. For me today, the break came in the form of a blue plastic bag, air-filled and snagged in the flatness of sand. Or so I thought upon approach.

A sight very familiar to Australia and New Zealand, but one also visible in other parts of the world, including Florida is the blue bottle jellyfish. It’s the Physalia physalis, commonly called a Portuguese man-o-war, a name borrowed from the 16th century sailing ship of English (rather than Portuguese) design. Australians have given the smaller jellyfish with one long, blue tentacle washing up on their beaches in large numbers the name blue bottle, from its form and color—on the land it has a bottle-like form and a blue color.

Weird science for sure, but the blue bottle is not a single animal but rather a colony of four kinds of individuals known as polyps, each with its own function. One is the float, another captures food, another digests the food, and another is responsible for reproduction. Though it certainly looks in part like a blob of jelly, this type of animal is not a true jellyfish but something called a siphonophore. Some danger involved, because the blue bottle can deliver a painful sting if touched—either in the water or when washed up on the beach. Advisable never to touch one with bare skin. Blue bottle stings can be extremely painful and can cause a fiery rash which lasts an hour or more. The venom filled tentacles also protect the animal from large predators. Toxins in the venom are strong enough to paralyze large fish, if not kill it, enabling the blue bottle to ‘sail’ safely away.

In appearance, the pear-shaped float (bottle) is a translucent blue, with a wrinkled top that looks very much as though it were sewn together with red or pinkish thread. It has one main, long tentacle and many shorter tentacles, all of them blue and hanging from the float. The float is anywhere from 2-15 centimeters long and the main tentacle about a meter in length, but sometimes much longer. The blue float acts as a sail and the jellyfish is blown along by the wind. Depending upon a left or right lean of the float, direction will change. Wind will sometimes blow individuals onto a coast, washing them up on beaches. Blue bottles are more common on exposed ocean beaches after strong onshore winds, and rarely found in sheltered waters. Their diet includes small fish, crustaceans, plankton, and other small marine animals. Special tentacles catch and paralyze prey, while other tentacles digest the food. Reproduction is a complex process, with special tentacles on the jellyfish having both male and female parts. In its simplest form, eggs are fertilized, grow into larvae and eventually develop into adult blue bottles.

Beyond all the complex biology, sight of one of these odd-looking creatures is enough to slow the pace of anyone walking the beach. The average person will stare down at a grounded blue bottle with its pink stitched bag-sail bobbing in the wind, and face stretched into a grimace murmur, “What the blue blazing hell is that?” The bottom photograph shows what looks like a creepy invasion of blue bottles on a beach in Australia, but here in Florida they aren’t so numerous. Only seven or eight of them over a three mile stretch of beach today.