A global increase in jellyfish populations is expected to hit Israel, scientists warned this week. Large numbers of jellyfish have been spotted in the Mediterranean Sea, on their way to Israel's coasts.

The jellyfish are expected to hit Israeli beaches in the near future. Those seen on their way to Israel are not usually dangerous, but they can leave swimmers with painful stings.

Public health officials warned swimmers to look out for jellyfish, to wash stings with vinegar or salt water, and to seek medical help if they experience serious pain after being stung.

Jellyfish numbers are going up worldwide, primarily in southeast Asia, the North Sea and the Gulf of Mexico. The marine animals often feed on fish eggs, making them a threat to local fish populations.

Ecologists believe the primary reasons for the soaring jellyfish population are overfishing and pollution. Overfishing reduces the population of fish species that are the natural predators of jellyfish, while pollution creates nitrogen and phosphorus-rich patches of ocean where fish are unable to survive, leaving jellyfish able to take over the area.

Marine biologist Dr. Anthony Richardson, who has researched jellyfish population trends, said this week that governments should “take management action to avert the marine systems of the world flipping over to being jellyfish dominated.” Among the actions Richardson suggested were reducing fishing, cutting back on pollution, and killing jellyfish to reduce the population.