Off the coast of Trieste large quantities of jellyfish have currently gathered in the water, drifting just below the surface and in some areas dominating the coastal waters. Italian reports indicate that the animals are currently distributed across the gulf in unusually high concentrations, noticeably altering the appearance of the sea.
Favorable conditions for jellyfish
Coverage of the development has been provided by, among others, Rai News as well as the online portal Il Post. There, the phenomenon is described as a "tappeto di meduse" a dense carpet of jellyfish stretching across large expanses of water. The reporting also draws on assessments from regional research institutions in the Trieste area.
According to Italian sources, these are so-called jellyfish blooms, a natural phenomenon that occurs regularly in the Mediterranean. Such aggregations form when jellyfish populations multiply rapidly under favorable conditions and are subsequently concentrated near the coast by currents.
Environmental factors as triggers
Several factors contribute to this development: rising water temperatures promote the reproduction of certain species, while currents and wind conditions, in particular regional winds such as the Bora, drive the animals into the gulf. The comparatively enclosed character of the Gulf of Trieste amplifies this effect, as the exchange of water with the open sea is limited.
In the current situation, the phenomenon is especially pronounced, as the jellyfish are not confined to the surface but are present throughout large portions of the water column. This has practical consequences for local fisheries: nets become strained or clogged by the sheer volume of animals, which partially disrupts operations .
Developments in recent years
Similar situations have been observed in the region on multiple occasions, including in recent years. Italian sources note, however, that such events may now be occurring at shorter intervals. Changing environmental conditions in the Mediterranean, in particular rising temperatures, are cited as a possible underlying cause.
For visitors to the region, disruptions are generally only temporary. Depending on the species of jellyfish, skin irritation may occur, but serious hazards are rare and typically confined to the affected coastal stretches.