Invasion by the Portuguese Man of War

Posted By Charissa / December 29, 2011 / Tybee Today / 0 Comments

Invasion by the Portuguese Man of War – December 29, 2011

Tybee’s beach got invaded last week by dozens (if not hundreds) of floating blue Portuguese Man of War. Most were seen washed up along the high tide line, and they looked like small (4-6 inch) oblong blue balloons with a tangled mass of short tentacles hanging from below. Although often considered as a kind of jellyfish, a Man of War is actually a “colony” of individuals living together and forming a single animal. The blue float is one type of individual, and 3 other types (for feeding, defense, and reproduction) form the mass of tentacle-like strings below. It’s those defensive tentacles, that can be 60 ft or longer, that cause the powerful stings that the Man of War is known for.

They get their name from the large blue float that apparently resembled the Portuguese sailing ships of the past. Along the top of that float is a ruffled ridge that is slightly off-kilter to the right or left; and as the wind blows them, they will “sail” to either the right or left of the direction of the wind. So as our group of invaders was getting blown ashore recently, about the same number were being blown off shore or along shore. For the most part, the Portuguese Man of War is a tropical, pelagic (open ocean) species; but when the winds and currents are just right, numbers of them can be driven long distances and onto shorelines.

Although we had a few come inshore this past summer briefly, the largest number I’ve seen on Tybee previously was many years ago, but again during December. Although they look harmless on the beach, the tentacles can still deliver a powerful sting, so it is best not to handle them. Many different treatments for Man of War sting have been tried and studied, and most studies have found variable and even conflicting results. So the most common recommendation is to carefully remove any remaining tentacles that might still be on the skin, and spray (don’t rub) 4% Lidocaine solution on the area; and possible apply ice to reduce the pain.

Dr. Joe Richardson (Ph.D. Marine Sciences) has studied marine life along Tybee Island for more than 30 years, and he leads his Tybee Beach Ecology Trips for families, schools and other groups year-round at Tybee Island.


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