Portuguese Man o' War

Portuguese Man of War, Alexandra Headland. January 14, 2012.

Portuguese Man o' War, or Blue Bottle, Physalia physalis, on rock on Alexandra Headland, between Mooloolaba and Maroochydore. Very often people call these creatures "jellyfish" but in fact it is a colony made of several types of different organisms. It has a "balloon" filled with gas to stay on the surface of the water and tentacles up to to 50 meters long. The colony use the tentacles to catch small fish. The tentacles are equipped with stinging cells which venom can paralyze a pray. People are also sensitive to the venom. 

Physalia cannot swim but float passively, and occasionally can be thrown on shore by wind or waves as on the picture. 

The photo was taken on cloudy day with Fuji X10 as a medium resolution JPEG, F7.1, iso 200, exposure compensation -1.0, 1/75 sec, supermacro mode, handheld. The different types of polyps are visible on 100% crop below. I included the biggest clipped highlight area on this crop in order to illustrate the absence of orbs on natural objects.

Another blue bottle picture is on my flickr page.