BERLIN, Aug. 17 (Xinhua) -- German coastal authorities have issued a formal warning to bathers in Schleswig-Holstein on Friday not to enter the Baltic Sea due to an unusually high incidence of poisonous jellyfish sightings.

The step was announced after the German Life Saving Society (DLRG) was called to render first aid to around 120 bathers on Thursday and received a further 600 complaints of individuals experiencing painful stings by lion's mane jellyfish.

Jan Cramer, the director of the DLRG watch in the seaside resort of Travemuende, said that no new jellyfish sightings were made on Friday but warned that the poisonous tentacles of the lion's mane species were still drifting in waters off the German coast.

Although lion's mane jellyfish cannot breed in the Baltic Sea due to its relatively low levels of salinity, marine biologists have nonetheless observed a significant increase in local populations in recent years.

The development is widely believed to be a consequence of ongoing climate change, with warmer Baltic waters encouraging more local plankton growth upon which the lion's mane jellyfish rely primarily for their nutrition.

Sometimes referred to as the giant jellyfish, the species usually inhabits cold waters in the Arctic, Northern Atlantic and Northern Pacific Oceans and can grow up to 37 meters in length and 2.3 meters in width.