Egg-Yolk Jelly

Phacellophora camtschatica

Phacellophora camtschatica, commonly known as the Egg-yolk Jelly, is a large jellyfish characterized by its distinctive yellow center that resembles an egg yolk, surrounded by opaque white tissue. This species can reach a bell diameter of up to 60 cm and is easily identified by its 16 clusters of tentacles, each extending up to 6 m in length. It is often confused with the lion's mane jellyfish, but its unique coloration and structure help differentiate it. This jellyfish primarily inhabits cool waters, found in various parts of the Northern Pacific, including the Sea of Japan and the Sea of Okhotsk, typically at depths ranging from 50 to 330 m, although it can be found shallower in some areas. Egg-yolk Jelly feeds mainly on gelatinous zooplankton and smaller jellyfish, capturing prey with its tentacles that contain nematocysts. Its life cycle includes both a polyp stage, where it reproduces asexually, and a medusa stage, where it reproduces sexually in the water column. The jellyfish releases fertilized eggs that develop into planulae, which then settle and transform into polyps before maturing into medusae. Divers may encounter the Egg-yolk Jelly drifting in open water, often in isolation. Its weak sting makes it less of a threat to humans, allowing for close observation. While the species is not evaluated by the IUCN, it is generally considered to have low abundance in open marine waters, though it can dominate in certain areas. Observing this jellyfish provides insight into the complex interactions within marine ecosystems, including its relationships with symbiotic species like larval crabs.