Pacific Sea Gooseberry (Pleurobrachia bachei)

Description: Pleurobrachia bachei goes by many names: cat’s eye comb jelly, sea walnut, and most commonly, Pacific sea gooseberry. This organism is known as a jelly, but it’s not a true jellyfish. Rather, it’s a comb jelly, or a ctenophore. There are many key differences between comb jellies and true jellyfish, here are a few: 1) comb jellies are ctenophores and true jellyfish are cnidarians, 2) true jellyfish have long stinging tentacles and oral arms that they use to grab food, and comb jellies have rows of combs that consist of cilia (AKA little hair-like structures), and 3) true jellyfish exhibit what is called radial symmetry while comb jellies exhibit biradial symmetry. Pacific sea gooseberries are small, round, clear, and divided horizontally into multiple sections. Its actual body usually only reaches diameters of 2 centimeters, but its two trailing tentacles can be up to 15 centimeters long.

Habitat: Pacific sea gooseberries are usually found washed upon the shore by beachgoers, but in the ocean they are found in swarms in surface waters near the shore. Geographically, they range along the Pacific Coast of North America from southern Alaska to northern Mexico.

Diet: Their prey consists of eggs, larval fish, mollusks, copepods, and other tiny organisms that can fit inside it. Similar to jellyfish, Pacific sea gooseberries grab their prey with their tentacles and pull the food into their mouths. Their predators include sea creatures like fish and large jellyfish such as the moon jelly (Aurelia aurita). 

Tide Pool Tidbits:

• Like other ctenophores, the cilia of Pacific sea gooseberries create a flashing rainbow appearance when they move underwater. 

• Their lifespan lasts only 4-6 months.

• The bodies of Pacific sea gooseberries are made up of 99% water.

References: Central Coast Biodiversity, Vic High Marine