15 Jul 2013

Bygone Waters of the Adyar Estuary

This post was published as an article in Life in Adyar, a newsweekly on 15th September 2012. 


The Adyar River originates from Chembarambakkam Lake in Kancheepuram district and flows 42 kilometers East-ward to confluence in the Bay of Bengal. Before merging into the sea, the river forms a unique ecosystem with a mixture of fresh and salt water, termed as Estuary or Mugathuvaram (river-mouth) in Tamil. Estuary originates from Greek word aestus which means tide or boiling of the sea. As the name suggest, this ecosystem is dynamic as sea water is flushed back and forth, throughout the day, due to action of high and low tides.

Fish, crab and prawn enter the estuary to lay eggs. Once hatched, the juvenile fish use the estuary as nursing grounds. Fish feel safe from predators hiding behind the roots of mangroves and on land, the lush branches of mangroves provide home for birds, even some migrants. Mangroves are plants which require both fresh and saline water for their survival and they are an integral part of an estuarine ecosystem. Mangroves draw nutrients from water since the river deposits rich silt and essential nutrients along with the flow. In turn, mangroves support the estuary by supplying organic matter, through litter such as leaves, fruit, bark and flowers. The organic matter is further broken down by microorganisms which ultimately become food for fish. The coastal areas are enriched by presence of the estuary as it supplies food for life forms in the near shore areas, ensuring a complete ecological cycle. Although, the estuary is located close to sea, the species which inhabit the estuary and the sea are completely different. 

Unfortunately, this would have been an ideal sight of Adyar estuary few years ago. Rapid urban development and improper management of our city’s waste has altered the estuary, conversely, declining its ecological wealth.


Sewage and encroachment in the Adyar estuary 


Adyar estuary was once home to wide variety of fish, crabs, prawn and shells. Many fishermen were directly dependant on the estuary for sustenance as it harbored few fish species of economic importance. However, the decline in the diversity of fish species can be attributed to the introduction of an invasive species.  According to literature, in the early 1950’s, 15,000 individuals of Tilapia fish (Oreochromus mossambica) were released from below Saidapet Road Bridge. Unfortunately, initiatives to boost fisheries lead to the displacement of commercially important species of fish, in the estuary. A simple definition of an invasive species is any organism which has the capacity to take over native species and create a proper home for itself.  Tilapia are contenders of “100 of the world's worst invasive alien species" enlisted by the International Union for Conservation of Nature (IUCN). Tilapia, a native species of Africa, mostly inhabits freshwater bodies such as lakes, ponds and rivers also extensively bred for the aquarium industry. Within few years after introduction, it was in 1958, Tilapia was starting to be reported in fishermen's catches from the estuary. Mullets (Mugil Cephalus), known as Madavai in Tamil, were the first victims. Pearl Spot (Etroplus suratensis), “One of the most economically important species of fish” during the 1950’s were displaced by Tiliapia without any trace, three decades later. Similar parallels can be drawn from Lake Victoria in Africa, the second largest lake in the world. An invasive species, Nile Perch was introduced into the lake to boost fisheries and it displaced nearly 300 species of fish. Fishermen on one side, gained export exchange out of it. However, Hubert Sauper, in his documentary Darwin’s Nightmare, shows the other side of this fishy tale

The Adyar estuary is well connected to the sea through a small opening, called as the river mouth. However, the estuary is cut off from the open sea for a period of 6 to 9 months. The closure of the river mouth is due action of water currents. Have you noticed? When you leave your bag on the beach and go for a swim, you always notice yourself ending up far away from your bag or friend, placed on the shore. You won’t even realize that you have moved far off. This is due to the action of long shore currents or long shore drifts that flow constantly along Chennai coast. Usually, the flow is towards South to North for 9 months and North to South for 3 months.

The problems of waste management grew along with the rapid urbanization of Chennai. Most of us don’t even know what happens to the garbage once it leaves our dustbins. However, we see them being piled up somewhere and burnt or dumped near water bodies which will ultimately end up in the sea. Unlike us, fish breathe through their gills requiring certain amount of oxygen dissolved in the water. Due to increased outlet of domestic sewage, most of the dissolved oxygen is used up by microorganisms. Once the levels of dissolved oxygen level decrease, it leads to the mortality of fish in that particular water body. Contamination of the estuary is another important factor which promotes the succession of invasive species such as Tilapia, since they are adapted to survive in harsh conditions.

It has been argued that slum communities along the Adyar River, are one of contributing factors to the pollution by encroaching the banks and reducing its breath of the river. However, the encroachment by high rise building and sewage which is silently dumped through underground sewers into the estuary is never spoken about.

The Adyar estuary is under peril. Cleaning up the river only in an aesthetic sense will never be of any help. The estuary will remain as an iconic example for the generations to come to learn how not to treat a river.

In two months time, the Fisheries Department has plans to introduce Tilapia into Poondi reservoir, which supplies fresh water to Chennai city. Once again, Tilapia will be cultivated in cages to boost aquaculture. Even if few fishes manage to escape the cages, then history might repeat itself, spelling catastrophe. It is time to think. Have we not learnt our lessons, already?


Rahul Muralidharan




25 Mar 2012

Into Infinity

The HECTOMETER freedive from william trubridge on Vimeo.


"The love of the diver for his world of wavering light. His world of pearls and tendrils and his breath at his breast. Born as a plunger into the deeps he is at one with every swarm of limegreen fish, with every coloured sponge. As he holds himself to the ocean's faery floor, one hand clasped to a bedded whale's rib, he is complete and infinite. Pulse, power and universe sway in his body"
- Mervyn Peake

24 Mar 2012

Coastal Ecology of Chennai - Ghost Crabs #1

Photo:Ghost Crabs (Ocypode sp.) of Chennai are facing a new threat. Commercial hunting and export for preparation of medicinal products. Location: Elliot's beach, Besant Nagar, Chennai.

Been to Marina or Elliots or any other beach in Chennai? Then, you must have surely spotted these guys. With alien like eye stalk and swift like agility, they keep shuttling back and forth, radiating around their tiny burrows which is their home. That is why they are called "Ghost Crabs".

Ghost Crabs, breathe through their gills and stay in their burrows when conditions are unfavorable, such as heat (afternoons), anthropogenic disturbance and cold spells (winter days). They usually feed during morning and evening hours of the day. Their food comprises for organic matters and sometime they even prey on baby sea turtles. I'm highly skeptical about these crabs ingesting plastics/debris or even microplastics for that matter.

Next time when you go to the beach, take time to observe these magnificent alien like life. When you start connecting with them, it transforms into an amazing experience. Just give it a try!

25 Oct 2011

When a whale dies, the story has just begun.

Death of a whale, commonly known as a Whale Fall creates a whole new micro niche at the place where it settles down. Here is a short video explaining the whole phenomenon.


Whale Fall (after life of a whale) from Sharon Shattuck on Vimeo.

8 Jun 2011

The Forgotten Mangroves of Chennai

     It was a Sunday morning in the month of April, 2011. Walking through the ipomoea matted roads with the sun on my face, felt so relaxing. I was walking to the Broken Bridge (500m from Elliots beach), where the sea meets the river, where the mangrove babies struggle their way out of the earth. Myself and few of my friends from Reclaim Our Beaches decided to visit the mangrove island down the river, where huge mangrove forest exist in secrecy from the city's atmosphere. A walk down the bridge showed me the degradation that the estuary has undergone. Dead fishes floating in the river, few were gasping for their last breath of air and fishermen collecting these fishes in the nets and transporting them to market. It was an awful sight. Couldn't do much!

Mangrove Forest, Adyar Esturay. Photo: Sid Hande
      We had hired a Catamaran to wade through the murky black waters of the Adyar river. Myself and my friend Sid Hande were the lucky two who made it on the boat. More than that and the boat would topple. Getting on to the catamaran and balancing ourselves needed some knack. And traveling for the first time in the estuary where I never would have even imagined, was an experience in itself. We had few crab friends as they hitched a ride with us tickling our foot and resting on our slippers.

Distant shot of Broken Bridge. Photo: Sid Hande
First few meters into the river and we were already amazed by looking at the mangroves surviving in the banks of the river. I was asking myself whether I'm in Chennai or some where else on earth. Moving closer to the islands, I was silently contemplating of how the estuary might have looked few decades ago when it was pristine. My vision was spilling all over. Addition to that Saravanan (fisherman/activist), our friend was telling joyous childhood stories of how he would come to catch shrimps in the estuary and silently sink into the lush mangrove forests. The boatman was telling his own stories of how he survived with group of friends, 18 days lost in the sea and finally found by the Indian Navy.

The boat ride was a revealing journey. Certainly it disproved my ideas about mangrove ecosystems in the city. Our initial ideas were to conserve the baby mangroves which grow near the Broken Bridge, but this boat ride threw light upon the existing biodiversity and the challenges faced by these mangrove forest. Once pristine, now these mangrove islands are flooded with Styrofoam, plastics and what not. This clearly shows waste mis-management practices in Chennai city. Even the uninhabited and isolated islands are victims of our ever growing trash culture.

While trying to look out for solutions, I stop and ponder whether have I been asking the right questions. 

Glimpses:

Photo courtesy: Siddharth Hande









12 Feb 2011

The Dutch Cemetery - Pulicat Lake, India.

This monument has gone around the sun 372 times and it still mourns for the dead, for the deceased and holds many stories to itself. These are photos from the Dutch cemetery, located at Pulicat Lake near Chennai. The Dutch were the first settlers at Pulicat using the lake as a means to navigate and transport goods. There are stories of outbreak of epidemics during the late 1600's which caused many deaths in the town which included babies and children. This cemetery stands as a remembrance of the lost souls, kings and queens, soldiers and diplomats, the rich and the poor. 

This cemetery comes under one of the important the heritage sites of Archaeological Survey of India 














Photos © Rahul Muralidharan

18 Dec 2010

Blue mysteries

 "There is one knows not what sweet mystery about this sea, whose gently awful stirrings seems to speak of some hidden souls beneath" ~ Herman Melville
 


 
Super Slow motion Surfer! - South Pacific - BBC Two from Denny Torres on Vimeo.



 


9 Dec 2010

The changing oceans

From pristine habitats to polluted sinks, our oceans has it all. While our knowledge about the oceans is evolving, there also seems to be a collective amnesia which makes humanity forget what is being done and what changes the oceans have encountered. This is what scientists call shifting environmental baselines. Commonly known as shifting baseline syndrome.

In his latest book "The Unnatural History of the Sea", Prof. Callum Roberts explains the phenomenon which is easy to understand. He states "The idea of shifting baselines is familiar to us all and does not just relate to the natural environment. It helps explain why people tolerate the slow crawl of urban sprawl and loss of green space, why they fail to notice increasing noise pollution, and why they put up with longer and longer commutes to work. Changes creep up on us, unnoticed by younger generations who have never known anything different. The young write off old people who rue the losses they have witnessed as either backward or dewy-eyed romantics. But what about the losses that none alive today have seen? In most parts of the world, human impacts on the sea extend back for hundreds of years, sometimes more than a thousand. Nobody alive today has seen the heyday of cod or herring. None has watched sporting groups of sperm whales five hundred strong, or seen alewife run so thick up rivers there seemed more fish than water. The greater part of the decline of many exploited populations happened before anybody alive today was born."



Oceans from Tom de Kok Teachings on Vimeo.

So when these baseline shifts happen, the environment that we live in becomes unpredictable and it takes every organism on the planet to adapt itself to sustain life.That apart, the quality of life degrades too. The present generation is already facing the brunt of our predecessors actions. The next generation, from ours.

These changes happen so subtly, that it is pretty hard to determine the impacts of even the minutest of shifts. If we take the city of Chennai, it is hard to imagine the fact that rich coral reefs and lush mangroves once existed in some of today's popular beaches in the city. When I heard from fishermen about how Chennai looked few decades ago, I literally had to ask them to come over again. What I heard was unbelievable, but true. Madras, as Chennai was formerly known, had rich marine biodiversity as it had been recorded by English scientists when India was under the rule of Britain. This raises the question how and why weren't the resources managed properly. At present, only the remnants of the rich past remains.

 According to the laws of nature, change is inevitable. Determining the changes for good or to its worse is in no one else's, but our hands.

Lets embrace changes and also make sure that the changes are for good.


2 Dec 2010

For the souls from the sea

"There is a pleasure in the pathless woods,
There is a rapture on the lonely shore,
There is society, where none intrudes, By the deep sea, and music in its roar:
I love not man the less, but Nature more."
                                               ~Lord Byron, Childe Harold's Pilgrimage

 

Technology in the deep blue

They were unknown, they were unexplored, territories uncharted but in the past. Welcome to the new era of technology which makes everything possible. Well, it can be used both for constructive as well as destructive purposes.


 Experiments and surveys in the deep blue oceans are considered a challenge, always. Reasons are many. Explorations in the past have resulted in dire consequences. In the present day world, technology plays a very important role. SONAR, ROV's , submersibles and what not, to carry out work with precision and perfection. A decade of study carried out by Census of Marine Life portrayed scenes beyond our wildest dreams, threw light on the exceptional environments and organisms in the oceans. And this was solely possible with the help of sophisticated technology.



Humans are certainly exploring the unknown and lets hope the rest is all for good.