Ocean Watch

By Susan Scott

Friday, November 2, 2001

Portuguese man-of-wars
drift at the mercy of winds

About five years ago, I worked with several people to find a remedy for the pain of jellyfish stings. Each month, when the box jellyfish came into Waikiki waters to spawn, we trooped down to the beach and applied hot packs, cold packs, meat tenderizer, Sting Aid and fresh water to people's stings.

Nothing worked. But we weren't finished. Because box jellyfish and Portuguese man-of-wars have different kinds of stingers on their tentacles, we wanted to try our stuff on man-of-wars, too. So we loaded our buckets with test materials and waited for the blue drifters to show up.

And waited. And waited. We waited so long that the meat tenderizer solution in the trunk of my car grew mold.

Entire years passed and still these pesky creatures did not appear on Oahu in any significant numbers. Then two weeks ago, while I was visiting relatives in Wisconsin, I checked my e-mail and found this: "Last week, Susan, walking on the beach was a hazard along the whole stretch of Kailua Bay. There were more man-of-war than I've ever seen, plus something more: They were clustered together in big blue bunches. ..."

Great. I look for these things for years, and then when I'm gone, whole rafts of them show up practically on my doorstep.

The reader went on to ask what attracts these blue stingers to our beautiful Kailua shores. It's a good question. Portuguese man-of-wars aren't attracted to our shores, or to any shores, in the least.

In fact, since getting beached is the death of them, these creatures are specially built to stay offshore.

Portuguese man-of-wars are wind-blown drifters, wandering around thousands and thousands of miles of open ocean. They stay afloat by means of an oblong balloon filled mostly with carbon dioxide. Stinging tentacles hang below, trolling for fish and invertebrates.

But these creatures don't just bob aimlessly. On top of their float lies a crest, which the animal can raise and lower. When the wind is on, the Portuguese man-of-war raises its crest and sails about 45 degrees to the wind.

When the wind blows really hard, however, the little blue boats get overpowered and drift directly downwind. That's why during periods of strong, sustained tradewinds, we often see Portuguese man-of-wars on our beaches.

But this happens only if some of the creatures are upwind of the islands at the time. This is unpredictable, because even though Portuguese man-of-wars roam the world's tropical waters, they don't do it evenly.

I have often been offshore in calm water and not seen a single man-of-war on the surface. Other times, huge armadas of the creatures surround the boat.

ONCE, while I was sailing several hundred miles west of the Big Island, the tradewinds stopped completely.

The wild Pacific suddenly became a big blue lake, and on top of this lake floated thousands, maybe millions, of man-of-wars. We dropped our sails (all million of us) and drifted together for days, waiting for wind.

The experience gave me an appreciation for the beauty, grace and remarkable adaptations of the Portuguese man-of-war.

And not only does this small creature sail, fish and reproduce in one of the harshest environments on the planet, its powerful sting can bring the toughest of us to our knees.

And perhaps one day we will learn what to put on those stings.

Marine science writer Susan Scott's Ocean Watch column
appears weekly in the Star-Bulletin. Contact her at

E-mail to City Desk

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