Is a box jellyfish sessile or motile?

Answer 1

Migration might be too strong of a term, but box jellies do demonstrate seasonal movement. During the spawning season (May - July) in Australia, box jellies congregate in the lower portions of freshwater rivers and mangrove channels. Their offspring then travel out to the coastal beaches during the wet season (Oct - Apr), where they grow to adult size and pose a serious threat to humans. Their life cycle completes when they travel back to the estuaries to sexually reproduce and then die.

There are dozens of box jelly species with varying life cycles and scientists are still largely unaware of the exact details, but the above description is generally true for the majority. Hibernation is not known to exist in these species.

Answer 2

The box jellyfish is motile (capable of motion). In fact, it can move more rapidly than other jellyfish thanks to its velarium that concentrates and increases water flow. It also has a more developed nervous system than most other jellyfish. In Australia, Hawaii, and Japan, among other areas, there are several species of extremely venomous jellyfish; people can die within a very short amount of time without treatment.

Answer 3

Jellyfish are sessile for part of their lives, but mobile for the rest.