Municipal officials in Phetchaburi's Muang district have warned tourists not to swim in the sea off Chao Samran beach while it is raining because of the threat of poisonous jellyfish.
Even on days when it is not raining, tourists should exercise extra caution due to the proliferation of jellyfish in the sea at this time of the year.
Although most of them are non-poisonous, some species are found to be poisonous such as jellyfish fire and box jellyfish.
Mr Boonyod Maklai, the municipal mayor, said that officials have erected safety net to cordon off swimming areas to prevent jellyfish from getting in so that tourists can swim in the sea.
Also as a precautionary measure against possible incidence of tourists stung by poisonous jellyfish, he said vinegar had been made available at several spots on the beach so that it can be applied to the victims to ease pain.
However, he noted that most of the jellyfish in the sea off Chao Samran beach are non-poisonous with only a few species which are poisonous and, so far, 10 people have been stung, but their conditions are not serious.
Duangtip U-ngoen, a scientist at Burapha University's Institute of Marine Science, identified two poisonous species in the sea off Chao Samran beach namely jellyfish fire and box jellyfish.
She said box jellyfish is more poisonous and its poison can kill or cause a person to become unconscious.
Thon Thamrongnawasawat, deputy dean of Fishery Faculty of Kasetsart University, meanwhile, said proliferation of jellyfish during the rainy season is quite normal, noting that fresh water that flows into the sea carries nutrients which cause plankton to bloom and plankton is food for young jellyfish.
Reduction of sea turtle population also contributes to jellyfish bloom because sea turtles prey on jellyfish, he said.
He admitted that it is difficult to prevent the proliferation of jellyfish during the rainy season. However, he said treating waste water before it is discharged into the sea can ease the jellyfish proliferation problem.
Source: Thai Public Broadcasting Service (Thai PBS)