Jellyfish blooms during ganapati immersions

The Economic Times , Tuesday, September 02, 2014
Correspondent : Vikram Doctor

MUMBAI: As the Ganapati festival comes to its annual climax, thousands of Mumbai's citizens are flocking to the city's beaches to immerse their idols in the waves. And not a few may receive a nasty shock or, more accurately, a painful sting. Year on year the reports of people reporting jellyfish stings during immersions seems to be increasing.

This is partly due to the festival's timing at the end of the monsoon, when its winds are still in force. Deepak Apte, chief operating officer of Bombay Natural History Society and a wellknown marine biologist points out that jellyfish tend to be pelagic (living in the open sea), but "change in currents and winds usually drive them to the shore.

It's a usual pattern but with increasing density, abundance of jellyfish contacts with humans are more frequent".

Once the festival is done though, the city forgets about the issue. Mumbai is one seaside city with, oddly, little interaction with its sea. People pay astronomical prices for a flat with a sea view, but only a few actually go into or on the sea. There is little waterborne transport, yachting is for very few, most swimming happens in pools, fishing is left to trawlers and the Koli community and even those who soak in the waves at Juhu beach tend to be visitors to the city.

If Mumbaikars interacted more with the sea they might realise that their seasonal jellyfish problems may be just one painfully visible tip of a much larger issue. Across the world jellyfish populations and the problems they bring are increasing dramatically, and stings are the least of the problems. Jellyfish have destroyed salmon farms and are killing fisheries by simply leaving no space for other marine life. They have shut down nuclear power plants and desalination facilities by clogging the pipes that bring in the seawater they use.

A spokesperson for Wabag, a leading desalination company, says their Indian plant has so far not faced a problem but they have faced jellyfish attacks in an overseas plant in Oman: "It lasts for about seven days and blocks the water path thereby [leading to] sometimes shutdown of the plant." He says power plants have also been seriously affected due to clogging of intake screens (for seawater which is used to cool the water used for cooling nuclear cores), which forces them to reduce their loads.

BF Chhapgar, a marine biologist, who used to run the Taraporewala Aquarium recalls being called years ago to advise the Tarapur Atomic Power Station on jellyfish. "They suggested using acoustic devices to scare them away, but jellyfish can't hear. Then they suggested electrocuting them, but I pointed out that sea water is a good conductor of electricity so they would electrocute everything else around!"

Chhapgar came up with a lowtech solution of multiple screens, so clogged ones could be removed and let dry. The jellyfish would shrivel and could be cleaned off. Solutions like this have proven effective, yet there are times when the sheer mass of jellyfish can be overwhelming. Jellyfish blooms are the name given to sudden population explosions and their extant can be amazing. In April-June 2000, a tomato-sized and coloured species bloomed along 1,200 km of the coast of Western Australia, causing a thick red band along the shore.

Jellyfish are not just a marine phenomenon, but are moving up rivers as well. In China, the completion of the Three Gorges dam on the Yangtze River around 2003 created a perfect environment for the lion's mane jellyfish (Cyanea).

In 1998, it was found in less than half a percentage of samples; by May 2004 it had grown to 98% of total catches, causing huge problems for fisheries. The Black Sea is another example, where run-off from unrestricted fertiliser use from surrounding countries lead to an invasive jellyfish becoming its dominant life-form and stifling most other fish life.

These examples are from marine biologist Lisa-ann Gershwin impassioned book, 'Stung! On Jellyfish Blooms and the Future of the Oceans'. Scary and devastating as the blooms are, she points out that the real danger lies in the conditions that have allowed these blooms to take place. Put succinctly, she says, "ecosystems are stressed and jellyfish are taking advantage".

Many of their natural predators have been killed off by overfishing or, as with sea turtles, destruction of their breeding habitats. Pollution is degrading sea shores and man-made climate change may be leading to warming and acidification of the oceans.

All of which, says Gershwin, is great for jellyfish. "They have been around at least 565 million years, and probably far longer... Jellyfish are among the world's most successful organisms, having survived freezes, thaws, superheated conditions, shifting and rearranging of continents, mass extinctions, meteor strikes, predators, competitors, and even man."

Jellyfish may look frail, boneless blobs of flesh and tendrils, but this weakness gives them adaptability to changes and by laying thousands of eggs they ensure many survive. Most creatures eat creatures smaller and slower than them, but jellyfish can eat larger creatures, and tangle faster fish in their floating tendrils. "Jellyfish target the eggs and larvae of species higher on the food chain than themselves," writes Gershwin. "And they also target the food that the larvae would eat." They are both predator and competitor and this is what makes them so efficient as marine usurpers.

Apte is much more cautious than Gershwin about the causes and effects of jellyfish blooms. The subject is complex, he says, but agrees that, "overfishing and loss of predators of jellyfish is one of the reasons in combination with increasing nutrient load from urban sewage waste, to make a perfect recipe for jellyfish bloom". While the jellyfish at Ganapati immersions may be due to the effects of monsoon winds, general overfishing and pollution may be setting the stage for a much more serious jellyfish menace.

A study by the Department of Aquatic Biology and Fisheries, University of Kerala has shown evidence of jellyfish bloom clogging the nets of trawlers particularly in the post monsoon season.

Perhaps one solution might be to follow the example of the Chinese and Japanese and start eating them. In Jerry Hopkins' book Extreme Foods, a survey of unusual edible items, he notes that jellyfish don't actually taste of anything, but are eaten more for their crunchy and chewy texture: "I've even been served jellyfish salad by several Asian airlines."

Hopkins concedes that some people describe them like eating rubber bands, but he points to the health aspects: "Jellies also offer a fat-free protein related to albumen, the egg-white protein, providing vitamins A and B." Our Central Marine Fisheries Research Institute has already developed a method to process some species of jellyfish for exports, so perhaps its time to look at domestic consumption as well.

Jellyfish stings might be painful, but they might also be nature's way of warning us of changes taking place in our marine environment, and if this cannot be stopped, then the changes we might need to make in our lives.

 
SOURCE : http://economictimes.indiatimes.com/opinion/comments-analysis/jellyfish-blooms-during-ganapati-immersions/articleshow/41817269.cms?prtpage=1
 


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