Lion’s mane jellyfish (Cyanea capillata) are named for their flamboyant, trailing tentacles suggestive of a lion’s mane. They can vary widely in size: While capable of attaining a bell diameter of over 2 m (6 ft 7 in), those found in lower latitudes are much smaller than their far northern equivalents, with a bell of 50 cm (20 in) in diameter.
These jellyfish can’t survive in warmer waters because they’re coldwater species. The jellyfish are pelagic for most of their lives but tend to settle in shallow, sheltered bays toward the end of their one-year lifespan. In the open ocean, lion’s mane jellyfish serve as floating oases for shrimp, medusafish, butterfish, harvestfish, and juvenile prowfish, providing both food and safety from predators.
Lion’s mane jellyfish live usually on the surface, at a depth of little more than 20 meters (66 feet). Because their modest pulsations are insufficient to propel them forward, they must rely on ocean currents to traverse long distances. During the late summer and autumn, when the jellyfish have grown to a big size and the currents begin to sweep them to shore, the jellyfish are most commonly seen. They are fully solitary, unlike most jellyfish, and rarely migrate in groups.
Video by Deep Perspective Diving
