Who lives on Chennai’s beaches? The Chennai Coastal Biodiveristy Guide has the answer

A red ghost crab on a Chennai beach   | Photo Credit: Vikas Madhav Nagarajan

When we relax on our favourite Chennai beaches, we have very little idea about who we are sharing that space with. Often, the creatures scuttling by, swimming past and flying overhead are not only residents of the beach, but also its architects, having lent a hand in shaping it over the years. Our sands are teeming; but, we have to know where to look.

“Lack of knowledge makes a place look barren when it is not,” says city-based naturalist M Yuvan, who is part of a six-member team that is documenting the biodiversity of this coastline and making it available for the public.

Besides what qualifies as strictly Chennai limits, the team is also including “a bit of Thiruvallur, Kanchipuram and Villupuram areas, that have similar sandy beach fauna,” he adds.

Meet your dune binders
  • We are often unaware of what to be grateful for, when it comes to our basic resources like potable freshwater: something we have access to despite living by the sea.
  • “Sand dune ecosystems give us freshwater. Where sand dune ecosystems are destroyed — for instance in North Chennai — are the spaces where seawater can then travel underground, into our freshwater ecosystem. You take away the sand, and this is what happens,” says Yuvan.
  • The character that build these sand dunes in the first place is the spinifex, informs Yuvan. These humble-looking coastal plants “create this hydrology by arresting sand, stabilising it and letting it build over centuries”.
  • Since these plants don’t look impressive, they are often dismissed as “just another random plant growing on the side. But if you live in Besant Nagar and you have freshwater to drink, you have to thank this plant,” states Yuvan.

So far, the online guide — which can be viewed on the citizen science website iNaturalist — lists over 315 species, including mollusks, crabs and other crustaceans, jellyfish, birds, algae, mangroves and more. And they still have many to add.

“We haven’t even begun listing the butterflies and insects yet. There is also a lot of local movement to be tracked, for example those between longshore and offshore organisms and creatures that can be spotted at low tide or high tide,” says Vikas Madhav Nagarajan, who is part of the team along with Yuvan, Rohith Srinivasan, Nandita Ram Satagopan, Anooja A and Aswathi Asokan. But while the team collates the final data, the real contribution comes from much larger groups of people on the ground, says Yuvan.

“We have been working with coastal communities and fishing villages along the Chennai coast. We are building a relationship with the fisherfolk of Urur Kuppam [Besant Nagar], Nalla Thaneer Odai Kuppam [Thiruvottiyur], Valmiki Nagar and Pattinapakkam, so that we can work together. We go and observe their bycatch, and they call us if they find something interesting as well,” says Yuvan.

Blue buttons on a Chennai beach

Blue buttons on a Chennai beach   | Photo Credit: M Yuvan

The team began this task in September 2020 and is still on it, says Vikas. Why? Because our shoreline populace differs from tide to tide, from season to season, from night to day. Besides winter migratory birds like the greater and lesser flamingos, there are other guest appearances to be tracked – by smaller, lesser-known yet oddly intriguing creatures. Stunning, jewel-blue, jellyfish-like Porpita porpita, for instance, dot the city’s shores between January and March and make for a lovely sight (from a safe distance) if you know where to look.

And then there are the creatures we might not even realise we are looking at. living, breathing, stationary beings that we often dismiss as just another structure of the beach. For instance, says Vikas, “At high tide at Kovalam, there are a lot of rocky patches created by man-made structures, where I can observe many barnacle species in action — their polyps can be seen coming out. Sometimes, the sea anemones will be alive as well.”

Indian spot-billed duck in Chennai

Indian spot-billed duck in Chennai   | Photo Credit: Vikas Madhav Nagarajan

Nocturnal creatures provide a challenge. “We think there are some nocturnal hermit crabs that we have not seen yet. We have seen tracks of very large hermit crabs at Mudaliar Kuppam and Pulicat, but we don’t know where they are. All the tracks seem to lead to dense vegetation,” says Vikas.

While canvassing for the Save Chennai Beaches campaign, Yuvan and his friends were surprised to see people refuse to sign petition letters to protect the beaches, while sitting on the sands and enjoying them. “It is very difficult to love something if you don’t know its name; if it is not a part of your mind and your imagination,” observes Yuvan. “That is why field guides work. And in our guide, we have also included Tamil names that the fisherfolk use for these species.”

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Printable version | Jun 18, 2021 11:24:41 AM | https://www.thehindu.com/sci-tech/energy-and-environment/online-guide-for-chennais-coastal-biodiversity/article34393687.ece

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