Siphonophores are spectacular animals. Not only do they often look bizarre, they are also exceptionally built. A Siphonophores consists of a colony of individual polyps. The individuals can have different tasks such as collecting food (gastrozoids), providing buoyancy (pneumatophore), providing propulsion (nectophore) or reproduction (gonophore).
Most Siphonophores float in the water, aided by the pneumatophore, a vesicle with gas in it. Some, such as the notorious Portuguese man-o-war, have a floating body with which they float on the surface of the water. Most Siphonophores are carnivores and have stinging cells to catch prey like fish, copepods and other crustaceans. They can also be dangerous to humans at times!
Siphonophores are often very fragile and in a plankton net they usually fall apart completely, so you can only find some loose nectophores. Fortunately, the shape of the nectophores is often characteristic for a certain species.
Siphonophores are rare in Dutch waters; they are mainly animals from the open ocean. In 2018, however, we found quite a number of small Siphonophores in the North Sea!