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Pyrosome video that a guest of Miguel’s Diving shot receives many gasps and questions from those watching it. What is this creature?
Pelagic, Colonial Tunicates
Actually, the strange cone is a colony of Pyrosomes. They are colonial tunicates found floating in the open ocean. As such, they are pelagic. They live and move within a few meters of the ocean surface.
Tunicates are a marine animal with bodies basically shaped like a tube. Some live as single individuals attached to the reef. Others float freely in oceanic waters; these are the pelagic ones. Others live as colonies in a jellylike cloth or tunic. Colonial tunicates can live attached to the reef or to another hard object. Other colonial tunicates live in the open ocean. So, Pyrosomes are pelagic, colonial tunicates.
A Rare Pyrosome Video
Should any scuba diver chance to see a Pyrosome colony, that would be considered an extremely rare event. A Pryrosome video is even more remarkable. As you watch the video, notice that the Pyrosome colony looks fuzzy. Actually, each tiny bump is an individual tunicate. Watch as the colony swims past the sunburst. Each of those black dots is an individual Pyrosome. All are embedded in a common gelatinous body.
A single Pyrosome measures only a few millimeters in size. As with all tunicates, one tiny Pyrosome pulls ocean water inside its body from an outside opening. It filters out plankton to eat. Then it pushes the used water out its other opening. In Pyrosomes, all the expelled water goes into the center of the Pyrosome cone. Then the water is expelled out its common, large opening.
Also notice in the video some holes in the Pyrosome cone. Evidently, a predator has nibbled some of it.
Clones of the Ocean
A colony of Pyrosomes are actually a collection of clones. Tunicates can reproduce sexually. A tunicate born in this way will float as a single larvae in the open ocean. Among colonial tunicates, the single new animal will then start to reproduce asexually. Basically, it makes a clone of itself. As the colony grows, the reproduction process by cloning continues.
A Pyrosome colony begins small. In fact, the day before this video was shot, guests of Miguel’s Diving encountered a small colony. It looked like a fuzzy thimble. Over time and in favorable conditions, a colony can grow to over ten meters in length. Its opening can expand to over two meters – large enough to enclose a human! However, remember that Pyrosomes only eat plankton filtered through those hundreds of thousands of tiny individuals.
Light and Movement
The scientific name of this genus is Pyrosoma. That comes from two Latin words pryo “fire” and soma “body.” Pyrosomes are famous among sailors on the open ocean for their bioluminescent abilities. Unlike other creatures that can bioluminesce, Pyrosomes can emit sustained light that can be seen for up to ten meters away. This is particularly notable at night. One Pyrosome can emit light, which in turn triggers a response from its neighbors in the colony. This looks like flashes of light. The entire colony can also light up. Their blue-green light can be seen up to 30 meters away. Moreover, one floating colony that lights up can elicit a light response from other Pyrosome colonies floating nearby.
Each individual Pyrosome has tiny hairs. These are called cilia. They move to create a current that brings plankton inside its body. All the individual Pyrosomes expelling used water through the colony’s opening also creates a current. Consider this motion as jet propulsion. Members of a colony can coordinate these motions and move itself through the water column.
Although any diver’s chance to encounter Pyrosomes is rare, guests of Miguel’s Diving can see wonderful marine life. To make arrangements for your trip to Gorontalo, please book your dive trip with us.