The public have been advised to exercise extra caution while in or near the sea because of an increase in the presence of Portuguese man-o-war.

A government statement said that Portuguese man-o-war can be identified with their bluish gas-filled float on top of the water.

It added: “However, their in-water tentacles are often not seen, making them deadly predators for small fish and extremely painful for humans after contact with the skin.

“People should keep their distance and refrain from touching the Portuguese man-o-war even if they wash up on the beach, as the tentacles can still be very venomous.”

According to the website American Oceans (americanoceans.org), “the man-o-war’s sting generally subsides after 30 minutes, leaving raised red patches on the skin. Some may experience fever and muscle pain. Nausea and vomiting might also occur.”

It added that the increase in population is likely owing to warming oceans. “Global warming is resulting in rising ocean temperatures and reduced oxygen levels in the water.

“While detrimental to many marine species, this combination has created an environment where both jellyfish and the Portuguese man-o-war thrive.”