The bell can grow to more than 3 feet (1 m) in diameter, while the trailing tentacles can get to 12 or 15 feet (3.6 to 4.6 m) long.

The bell is semi-transparent with either a white or reddish-brown tint to it. Usually the bell is striped. Pacific Sea Nettles are larger and darker than their cousin the Northern Sea Nettle (Chrysaora melanaster). They also have long lace-like oral arms in the center that transport food to their single mouth opening on the underside of their bell.

Pacific Sea Nettles feed on fish, zooplankton, and other jellies.

The lifespan for a Pacific Sea Nettle can be anywhere between 6 to 12 months. However, in the wild they can live closer to 18 months.

Sea Nettles, like most jellyfish species, travel in swarms. A Sea Nettle’s sting is very often deadly to proportionately sized prey. Their sting is rated from moderate to severe in regards to human interaction.

The jellyfish sting actually comes from tiny nematocysts, or stinging cells, on the jellyfish body. When triggered, these cells eject poison-tipped barbs that help the jellyfish catch food in the ocean. The nematocysts can still release their sting even after the jellyfish is dead.

Individual sea jellies are either male or female and reproduce sexually. Eggs and sperm develop inside the gonads and are released through the mouth into the ocean. The microscopic fertilized eggs begin a series of cell divisions which results in an embryo. The embryo does not develop directly into a baby sea jelly, but instead becomes a “planula”. The planula is either carried with the current or uses cilia to swim until it finds its final resting place. After the tiny planula attaches to a rock or other substrate it immediately begins to grow into a polyp. The polyp can feed on passing plankton with its upward-facing tentacles. Grooves begin to appear and get deeper and deeper, cutting through the polyp’s body. The polyp then clones itself and reproduces asexually. A pile of disc-shaped structures emerge and one by one start to break away, each becoming a baby jelly, also called a free floating medusa. This is the form that most people recognize as a sea jelly.


Chrysaora fuscescens

Type: Invertebrates

Diet: Zooplankton

Average Life Span: 6 mo – 1 year

Size: 30 inches wide (tentacles can be as long as 16 ft)

Weight: 0.2k

Conservation Status: Least Concern