Kerala’s Vembanad Lake: Averting an ecological crisis

DW (English)

Pollution and shifting salinity threaten Kerala’s largest wetland—and its prized clam beds. Scientists and residents are working to save lake and livelihoods.

Transcript

00:00Vembanad Lake is the beating heart of the cultural, social and economic life of the

00:08South Indian state of Kerala. For fisher folk like 65 year old Ambika, Vembanad holds the

00:15key to their livelihoods, specifically a dark-shelled mollusk known as the black clam found on the

00:22lake bed. Once the fishing boats reach their usual harvesting spots, their tools scrap the

00:29lake bed, shaking off mud and sand as the clams are pulled into the canoe. Nowadays the

00:36catch is much smaller than in years past. There has to be salinity in the water for the

00:43clams to breed. Without it there's no yield. Earlier saline water flowed in from the

00:49northern side and we had a decent harvest. Up to 70 percent of India's black clam come

00:58from these waters, harvested by thousands of fisher folk living around the Mohamma fishing

01:03village. Over the past decade, they stood by helplessly as black clam harvests shrunk by

01:09more than a third. These changes in the Vembanad Lake can be traced to the Thanir Mukumband, a

01:161.4-kilometer barrage about 20 minutes upstream that was meant to keep saline water from the

01:22sea in the northern half of the lake to promote extensive year-round rice cultivation. Aquaculture

01:28expert Dr. Padma Kumar says this can have unintended consequences.

01:32When the area is cut off from the sea, when sea water is delayed, the breeding requirement,

01:40environmental condition was not available. This has affected the natural breeding of the species.

01:46Back at Mohamma village, environmental consultant Manija Murli is taking stock of the day's black

01:53clams. She worked with an NGO and is helping villagers adapt to the changes in the lake's saline balance.

02:01She believes the solution lies in actively controlling the fishing activity.

02:06On the other side of the barrage where the salinity is right, we see many clams,

02:11including lots of baby clams in layers on the lake bed. So we started by collecting those baby

02:18clams with the help of villagers and clam fishers. Then we brought them to the southern side of the

02:23lake where the water is not saline and planted them in specific sections. We then treat this as a

02:30prohibited area for up to three to six months until the clams have grown properly.

02:35Manija's work alongside thousands of fisherfolk like Ambika is helping locals reimagine the lake as a common

02:47resource. Instead of fishing until the nets turn up empty, the catch is sorted and only mature clams are

02:55processed further. Juvenile clams are then returned to the lake. We should not over harvest juvenile clams.

03:03Why? It's important to understand that by leaving the baby clams undisturbed and letting them grow,

03:09we get much better returns when we harvest them at the right size. Small clams may fetch as little as

03:1690 rupees but choosing that quick return harms the resource. Their efforts are already bearing fruits

03:25and clam harvests are steadily rising. Fresh clams are always in demand with locals and tourists alike.

03:33The shells of black clam bring in additional income too. They are packed with calcium and are sold to

03:39industrial producers of construction materials like cement.

03:46For Manija, the involvement of locals has had knock-on effects for the whole region's ecological balance.

03:52Because the local community is involved in our awareness activities, we see their fishing habits are changing.

04:02They no longer exploit the resources beyond the limit and have become more aware.

04:11Now, if anyone in their community or even outsiders resort to overfishing, the community speaks up and

04:17reports it to NGOs like ours, so that a solution can be found.

04:21Improving clam harvest is just the first step. Their mission is to improve the overall biodiversity

04:31and sustainability of settlements around the lake. The villagers' next challenge is to mitigate the

04:37effects of tourism, farming and population growth in the region.

04:41The lake doesn't have as many clams that used to have, but it is full of plastic waste. And I feel this

04:49pollution is also one of the reasons that's affecting clam breeding.

04:55Teams of locals have started organising clean-up trips to fight pollution in the lake.

05:00They regularly test the water to monitor the ratio of dissolved oxygen in the lake. However,

05:08activities of tourism operators, rice farmers and households around the lake also have a major impact

05:14on its ecology. Dr. Padma Kumar says a plan that brings all these actors into line with the needs of

05:22Zambanard Lake is the need of the air.

05:28Enforce, I should say, crop calendar, restricting the crop season accordingly,

05:34and the scientific operation of the wattage, and allow the flushing of the lake. Because the lake is

05:42actually where the five rivers open, a lot of organic matter and the pollutants get accumulated.

05:51So the solution is to have a continuous flow of water to the sea.

05:57The residents of Mohamma village continue to set out on their boats into the heart of Kerala's

06:02backwaters. They are no longer just fishermen or women. They have also become the guardians of its survival.

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