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How citizen science is helping save Kerala's fish species

Read time: 7 mins
26 Jul 2018

On a sunny day in May each year, the backwaters of the Vembanad lake in Alappuzha, Kerala, come alive with the bustle of a hundred people talking about fish—Kerala's delicacy. No, there aren't any picnic baskets, but just books, water bottles and fishing nets! The chitter-chatter dies down soon as the visitors break-up into smaller groups, and take a cruise, albeit of a different kind! If you thought they are the ubiquitous tourists who throng the world-famous backwaters of the lake, you are mistaken. They are the volunteers of the annual Vembanad fish count who are on a mission to identify the hundreds of fishes in the lake.

But why the Vembanad lake, you ask? Well, with its scenic backwaters, houseboats and coconut trees, the lake is the longest and second largest in the country—a real gift to 'God’s own country'. Forming a significant portion of Kuttanad, the rice bowl of Kerala, it is the lifeline to fisherfolk, agriculturists, clam collectors and houseboat operators. It is one of the largest wetland system in India and is home to about 20,000 waterfowls—the third highest in India and many species of fish and clams.

The lake covers an area of 2033.02 km² and spreads over the districts of Alappuzha, Kottayam and Ernakulam. It is fed by Meenachil, Achankovil, Pamba, Periyar, Manimala and Muvattupuzha rivers that originate in the Western Ghats. The lake also has several islands like the Wellington island, Bolgatty island and bird sanctuaries such as Kumarakom and Pathiramanal. This wetland system is recognised as a 'wetland of international importance' by the Ramsar convention owing to the rich biodiversity here.

Caught in a 'barrage' of dilemmas

In the last few decades, like most other water bodies in the country, the Vembanad lake is under threat. The uncontrolled mining of clams, unregulated tourism, the release of sewage effluents from the cities and the pollution from the surroundings is taking a toll on the lake and its inhabitants. Besides, the lake is threatened by land reclamation efforts aimed to increase the area under cropping in Kuttanad, which is otherwise flooded. Farmers in Kuttanad pump out the lake water and use the reclaimed land, which is below the sea-level, for agriculture. In order to prevent entry of tidal water into the southern parts and  facilitate rice cultivation during non-monsoon periods, the idea of constructing a barrage in Vembanad Lake was conceptualized by the Government of Kerala.

In the 1950s, a proposal was made to construct a barrage to prevent the inflow of water from Kochi to Alappuzha under the Kuttanad Development Scheme. Eventually, the Thanneermukkom barrage was constructed in 1974 and began to function in 1976.

This resulted in the division of the lake into two parts - the northern or Kochi side and the southern or Alappuzha side.  The northern is largely saline that flows into the Arabian Sea, and the southern region is mostly freshwater. As the shutters of the barrage remain closed during December to March, when agriculture is carried out in the south side, the agricultural run-off adds to the nutrition of the lake, resulting in lowered oxygen levels and suffocation of fishes and clams to death.  The Thanneermukkom barrage is now posing as a threat to the ecology of the lake and also affecting the lives of fisherfolk and clam collectors, turning out to be a social issue.

Many ecological studies and observations in the past have reported a drastic reduction in the fish numbers and an extensive growth of invasive plants such as Eicchornia crassipes, the water hyacinth, and Salvinia molesta, commonly called as African payal, affecting fisheries in the region, after the construction of the barrage. For example, the Kuttanad Water Balance Study (1989) had reported 60 species of fishes from the southern side of the lake and 150 species from the entire lake. However, the Vembanad fish count of 2008-2011 recorded just 67 species. Although migratory species dominated the lake in the 1900s, there has been an increase in carnivorous and omnivorous fish, with a reduction in the number of herbivorous fish.

Hence, monitoring the changes in the wetland ecosystem and their magnitude serves as a data point for subsequent actions and interventions.

The birth of a citizen science movement

It is under these circumstances that a citizen science initiative, called the Vembanad Fish Count, was born ten years ago. Organised by the Community Environmental Resource Centre (CERC)- Ashoka Trust for Research in Ecology and Environment (ATREE), the Kerala University of Fisheries and Ocean Studies (KUFOS), Kochi, and the Federation of Vembanad Lake Protection Forums (Samyuktha Vembanad Kayal Samrakshana Samithi), Alappuzha, the event brings together experts, students, researchers, enthusiasts and fisherfolk.

“Volunteers are the backbone of the fish count. We get a wide range of applicants for volunteering, and we do not have any particular criteria for selection. Whoever is ready to learn and participate in the event are welcome”, says Mr Ashish Mathew George, Programme Officer at ATREE, who coordinates the event. The event sees participation from volunteers belonging to various parts of the country.

The event is held each year in May, a conducive period just before the rains as the whole of the past year's activity as well as the conditions prevailing for the next year can be recorded. The volunteers start their day in one of the many morning cruises that venture into the backwaters to document the fish species and numbers. The fish are caught from multiple locations using different types of nets and are identified. The collected samples are tediously processed and preserved for future reference. Besides counting the fish, the volunteers also record the water quality for monitoring purposes.

This year marks the eleventh anniversary of the fish count which saw a participation of 120 volunteers. It was the first time that the northern part of the barrage was also surveyed. “All these years, we have recorded about 55 to 60 species of fish in the southern side. This year, we recorded a total of 117 species, which is not a good sign as the numbers have dwindled from 150 species as reported in previous literatures. Puntius parrah, a species once found in abundance the Vembanad ecosystem has certainly reduced in number over the years as it is a freshwater species and the pesticides and fertilizer based stress in southern area is way high for its tolerance threshold to counter”, remarks Mr. Anu Radhakrishnan, a Research Associate at ATREE and a fish expert.

This year’s surprise catch included a mouth brooding fish Arius arius, a catfish, and two exotic species—the moonlight gourami (Trichopodus microlepis), and the shortfin molly (Poecilia mexicana), where the latter was reported for the first time from India.

Besides identifying the fish in the lake, the event also strives to bring together the other stakeholders of the lake and engage them in interactions. The fishermen identify the best fishing techniques suitable for the lake such as fish catching practices and period of fishing. The clam collectors are involved in the cleaning of the lake to make it free especially from plastics that kill the juvenile clams.

“An important achievement of ATREE is uniting the fisherfolk to have a role in the fish count where during various dialogues they realised the importance of the event. Now, they take a call on the fishing practices and suggest it to the government following a bottom-top approach”, shares Mr. Radhakrishnan with pride.

What do the volunteers get out of this programme? “When I heard about the fish count event, I was excited that I could see a lot of fishes that are native to Vembanad! I also intended to learn the techniques for catching and identifying the fish”, shares Mr. Sharat MS, an engineer by profession who volunteered in this year’s fish count. “I’m happy to be a part of such a big collective effort contributing to the conservation of these threatened aquatic lives”, he proudly declares.

The Vembanad fish count is an example of how bridging the gap between various stakeholders with a common interest helps in protecting the environment and securing livelihoods. As Benjamin Franklin rightly stated, “when the well is dry, we know the worth of water”, perhaps, the time is now?