ALAPPUZHA, INDIA - Flocks of storks and cormorants perched on bamboo stilts peer into the blue-black depths of Vembanad Lake in India's southwest Kerala state, searching hungrily for food.

"Around 200 fish pairs are breeding here, which is why predator birds are hanging around," said K. V. Dineshan, steering his canoe toward the tennis court-sized fish sanctuary, a fertile oasis in the degraded lake located in a protected wetland.

A barrage built by the state government divides the lake's 36,000 hectares in two: the northern part has brackish water all year round, while the southern half is fed with fresh water from rivers and seawater is shut out from December to April, allowing rice to be grown.

But grave challenges face the 7,500 fishermen like Dineshan who make a living from the southern part of the lake, which covers 13,000 hectares. They are struggling with low salinity which harms shellfish reproduction, water stagnation, pollution and agrochemical runoff.

Overfishing and the mounting impacts of climate change - including warmer water in the lake, a decline in winter rains and severe flash floods during the monsoon - are making matters worse.

The 1.5 million people supported by Vembanad, one of India's largest lakes, live off agriculture, fishing, clam collecting, duck breeding, coconut fiber production, tourism and water-based transport. But yields have been falling and times are hard.

Half the wetland's 150 fish species have been wiped out since the Thanneermukkom barrage was built in 1975, show fish counts by the Bangalore-based Ashoka Trust for Research in Ecology and the Environment.

So in 2008, a group of fishermen set up Lake Protection Forums, legally registered bodies across Alappuzha and Kottayam districts, each with 50 members, 20 of them women.

As well as setting up "no-fishing zones", the forums have tackled theft and also collect plastic waste which ends up in the lake following the annual pilgrim season in November and December.

Local people now understand that "their economic condition is directly linked to sustainable ecology management", said K. V. Jayachandran, former director of research with Kerala University of Fisheries and Ocean Studies. "Better health and cultural unity are other benefits."

Thomson Reuters Foundation