Orange-Striped Jellyfish

Gonionemus vertens

Gonionemus vertens is a small jellyfish with a transparent bell that typically measures 1 to 3 cm in diameter, occasionally reaching up to 4 cm. It has 60 to 80 tentacles, and the gonads are distinctly colored, appearing orange, red, or violet in females and yellow-brown in males. This species is primarily found in coastal regions of the Northern Hemisphere, particularly in shallow waters of the northwest Pacific, from the Russian Far East to Japan, and extending to the northeast Pacific, including areas like Puget Sound. It prefers depths ranging from the surface to about 2 meters, often attaching itself to surfaces such as seagrass during the day, which contributes to its common name, clinging jellyfish. Gonionemus vertens feeds mainly on zooplankton, including fish larvae and tiny crustaceans, primarily at night when it is in open water. Reproduction occurs sexually, with the release of eggs and sperm into the sea, leading to the formation of planula larvae that settle on substrates and develop into polyps. These polyps can reproduce asexually, allowing the species to thrive in various environments. The medusae stage lasts about three months, but the polyp stage can persist for years. Encounters with Gonionemus vertens can vary; while it is known to have a strong sting in some regions, in the northeast Pacific, it is considered harmless. However, caution is advised as stinging incidents have been reported in other areas, including East Asia and the Atlantic coast of the United States.