Mediterranean 'egg‑in‑eye' jellyfish collected by Pula Aquarium

Mediterranean jellyfish (Cotylorhiza tuberculata), locally called “jaje na oko” (egg‑in‑eye), have been observed in large numbers on Havajska beach in Pula. The Pula Aquarium captured several adult specimens and placed them in a new Mediterranean exhibit, where visitors can view the jellyfish up close. About ten juvenile horse mackerel (Trachurus sp.) were also found sheltering beneath the jellyfish bells.

The species is native to the Adriatic, can reach a diameter of roughly 30 cm, and its brown‑green hue comes from symbiotic algae. It lacks a stinging rim and has eight branched oral arms that produce only mild or no reactions in humans. Scientists note that milder winters, warmer sea temperatures and increasing concrete shoreline create favorable conditions for the jellyfish, and they expect its numbers to rise in the future.