Look what's swimming in the Slovenian sea

In recent weeks, swimmers along Slovenia’s Adriatic coast have reported seeing unusual creatures gliding through the waters near Portorož and other popular seaside resorts. These organisms, identified by experts as Cotylorhiza tuberculata, commonly known as the "sea egg" or "medusa," have become increasingly visible in the shallows, prompting both local residents and international tourists to take notice. The sight has sparked curiosity rather than alarm, as marine specialists confirm these jellyfish pose no threat to humans. The phenomenon appears to be part of a broader seasonal pattern, with reports indicating a rise in their numbers over the past several months. Observers describe the creatures as resembling large, translucent eggs, often measuring up to 40 centimeters in diameter, though many are smaller, typically around 20 centimeters. Their distinctive appearance, marked by a flattened bell and a central ridge surrounded by a circular canal, makes them easily identifiable. The coloration ranges from greenish-brown to reddish tones, further distinguishing them from other species. Local authorities and environmental agencies have received numerous inquiries from beachgoers who encountered the jellyfish while swimming or snorkeling. Some visitors, particularly from neighboring Croatia, have expressed surprise at the sight, capturing images of the creatures with their cameras. In response, officials have issued reassurances that these jellyfish are harmless to humans, emphasizing that they lack stinging cells capable of causing injury. This has helped calm public concern, though some warnings have been issued urging swimmers to avoid touching or collecting the animals. Experts from the Faculty of Natural Sciences in Pula, including Petra Burić, have noted that Cotylorhiza tuberculata plays a vital role in the marine ecosystem. Adult specimens provide shelter for juvenile fish, contributing to biodiversity and ecological balance. Despite their striking appearance, the jellyfish are non-threatening to swimmers, and there is no need for panic upon encountering them. However, Burić and others have advised against picking them up, stressing that they should remain undisturbed in their natural habitat. The presence of these jellyfish has also drawn attention to the health of the Adriatic Sea. While their increased visibility might seem alarming, scientists suggest it could reflect changes in water temperature or nutrient levels, factors influenced by climate change. Similar observations have been made in coastal areas of Croatia, particularly around the popular resort town of Zelenika and the cape of Kamenjak, where the jellyfish have been frequently spotted. Local conservation groups have used this opportunity to educate the public about the importance of preserving marine life and avoiding interference with natural processes. As summer continues, the situation is expected to evolve. Marine monitoring teams will likely continue tracking the population trends, while local tourism boards may issue additional guidelines to ensure visitor safety and environmental protection. For now, the sight of these peculiar creatures in Slovenian waters serves as a reminder of the dynamic nature of our oceans, and the delicate balance that sustains them.