Photo StoryPublished : Aug 23, 2018Updated : Sep 26, 2023
Hovering like surreal little spaceships, diaphanous freshwater jellyfish are the secretive, benign inhabitants of the sacred river of southern India
Text by: Riccha Paul | Photos by: Amoghavarsha
Hovering like surreal little spaceships, diaphanous freshwater jellyfish are the secretive, benign inhabitants of the sacred river of southern India
The sacred River Kaveri is the lifeline of South India. It originates on Brahmagiri Hill in southwestern Karnataka and empties into the Bay of Bengal in Tamil Nadu. Unfortunately, the river has become most talked about because of the dispute between the two states over its waters. But this river, often called “Dakshin Ganga”, has always been celebrated for its natural beauty and the legends that surround it. Within its depths are many secrets. One of them is a peculiar freshwater, non-venomous jellyfish, the craspedacusta sowerbii. Very little research or documentation has been done on these unique and beautiful creatures, and photographs of the species are few and far between.
Craspedacusta sowerbii is widespread in the rivers of the United States, as well as in the Yangtze in China, and has been observed in numerous other parts of the world. Only recently they have been noticed in the Kaveri and its tributary the Hemavathi River in south Karnataka.
Jellyfish are best admired from afar, especially because of their poisonous tentacles, which can deliver a sting that is extremely painful and sometimes fatal. The freshwater jellyfish Craspedacusta sowerbii, found in the Kaveri however, is a rather tame cousin of some of the infamous deadly ocean-dwelling species of jellyfish.
These tiny translucent creatures live in the River Kaveri in underwater colonies. They attach themselves to rocks and plants, near a sustainable food source. Their preferred environment is the bottom of shallow waters where they have the opportunity to stun and capture food and avoid predators. Under their tentacles, jellyfish have eye spots, which are areas sensitive to light, allowing them to sense if food or a predator is close by.
The Kaveri’s unique jellyfish are best sighted when the river water temperature is warm. They grow to a maximum of 2 to 3 centimetres in diameter with literally hundreds of tentacles. Jellyfish hunt with their tiny tentacles, which produce enough venom to paralyze their prey—in this case zooplankton and other tiny organisms. Research indicates that the amount of venom produced has almost no effect on humans, and the Kaveri jellyfish’s tentacles do not have the capacity to pierce human skin.
According to the scientific research that is available, when water temperatures drop, these jellyfish contract into little podocysts and are most likely transported around by aquatic plants and migratory birds. Once they are reintroduced into an environment that’s suitable to them, they come out of the cyst and resume their life cycle.
