CHENNAI: A routine dip in the sea is turning unexpectedly painful for many along the Chennai and north Tamil Nadu coast, as an unusual surge in sightings of the stinging jellyfish Chrysaora chinensis has been reported over the past week.
Divers and beachgoers have reported sharp pain, itching and rashes after being stung by jellyfish, prompting experts to advice caution in nearshore waters.
Marine scientists attribute the spike in sightings to seasonal and environmental factors. “This is typically the season when such jellyfish are more visible, especially with the onset of summer,” said Dr Pralaya Ranjan Behera, senior scientist at the Visakhapatnam regional centre of the Central Marine Fisheries Research Institute, who studies jellyfish bloom dynamics.
“Warmer sea surface temperatures act as a stimulus for reproduction, leading to a rapid increase in numbers,” he told TNIE. Pollution is also a contributing factor. “Nutrient enrichment in coastal waters, often linked to pollution, can indirectly support jellyfish blooms by altering the ecosystem in their favour. When combined with sustained warm conditions, it creates an environment where populations can expand quickly,” he explained.
Scuba divers operating along coastal stretches from Chennai to Cuddalore told TNIE that they have encountered significantly high numbers of jellyfish species in recent days. “We usually spot these jellyfish in small numbers, but what we are seeing now is unusual. Some of the tentacles extend well beyond two metres, increasing the risk of contact,” said P Venkatesh of Ocean Delight Scuba School in Kovalam.
Beachgoers, too, have reported being stung while wading or swimming in shallow waters. Though the species is not considered deadly, its sting can cause intense pain, skin irritation, redness and itching. “People should avoid touching jellyfish, even if they appear washed ashore, as the tentacles can still sting,” Venkatesh added.
With summer intensifying and sea temperature rising, experts warn that such blooms could become more frequent. They have urged the public to avoid waters where jellyfish are visible, and called for improved monitoring of coastal ecosystems.