COMPASS JELLIFISH | CHRYSAORA HYSOSCELLA

THE COMPASS JELLYFISH

Chrysaora hysoscella is a large jellyfish that lives in the Mediterranean Sea and the Atlantic Ocean. In Italian, it is known as the “brown jellyfish” due to the brownish hues on its bell. However, it is its English name that, in my opinion, describes its unique appearance in a much more evocative way.

In English, it is called the “compass jellyfish,” and the reason is quite simple: the dark triangle patterns on its low, round bell make it resemble a compass. This pattern, along with its long tentacles and oral arms that resemble an evening gown with a train, and its graceful floating movement, make it one of the most elegant and beautiful jellyfish in the Mediterranean.

In this series of posts, I have often talked about the function of the oral arms, but I haven’t taken the time to describe what jellyfish eat.

Jellyfish play a crucial role in the marine food web: by feeding on microscopic planktonic organisms, they provide a vital energy source for larger animals that prey on them. Specifically, Chrysaora feeds on tiny organisms such as dinoflagellates, copepods, crustacean larvae and eggs, as well as fish larvae and eggs.

The prey is paralyzed by the venom in the jellyfish’s tentacles. Once captured, it is passed to the oral arms and then directed toward the mouth.

Due to its considerable size, Chrysaora hysoscella has very few natural predators. Nevertheless, it is an essential part of the diet of the Ocean Sunfish (Mola mola) and the Leatherback Sea Turtle (Dermochelis coriacea).