Rare Compass jellyfish spotted in Croatian waters

A species of jellyfish rarely seen in Croatian waters has been spotted off the Istrian coast. Faculty from the Department of Natural and Health Studies at the Juraj Dobrila University in Pula confirmed that the Compass jellyfish or Chrysaora hysoscella had been seen in the northern Adriatic, between Rovinj and Venice, a month ago. It was more recently witnessed in waters off Pula.

The animals usually grow to 15–25 cm in diameter, although with their tentacles can reach up to one metre in length. The rather beautiful jellyfish usually has around 16 brown v-shaped markings on its bell, surrounding a central brown spot. This gives the jellyfish the appearance of a compass and, in turn, its common name.

These jellyfish are not regularly seen in the Adriatic. They travel alone or in very small numbers and are not greatly dangerous to humans, although their tentacles can leave a sting in the extremely unlikely event of an encounter. Interestingly, the Compass jellyfish can reproduce in the traditional manner, with a partner, or asexually, a skill of which some single people currently observing social distancing may be envious.

Jellyfish are animals, not fish, although they have no brains. 95% of a jellyfish's body is comprised of water (in comparison, the human body is about 60% water). In 1991, over 2,000 jellyfish polyps were sent into space to test how they reacted to the lack of gravity. They were able to reproduce in space and created over 60,000 jellyfish. Therefore, many more jellyfish have been into space than humans. Jellyfish have lived in the earth's oceans for over 500 million years.