Why saving Chilika lagoon’s seagrass meadows is key to water quality and fisheries

The health of a water body is often reflected in the lives it sustains. In Odisha's Chilika lagoon, one of India's most important coastal ecosystems, fishers are witnessing changes that extend well beyond declining catches. Waters once known for their ecological richness are becoming increasingly polluted, while seagrass meadows that support aquatic life and help maintain water quality are steadily shrinking.

This decline mirrors a wider global trend. Coastal ecosystems around the world are facing growing pressure from human activities and climate change. Among the most vulnerable are seagrasses, flowering marine plants that grow in shallow coastal waters and form extensive underwater meadows. These habitats provide food, shelter and breeding grounds for thousands of species, including fish, shellfish, dugongs, seahorses and sea turtles, while also stabilising sediments and improving water quality.

As seagrass meadows disappear at an alarming rate, the consequences are felt across entire coastal ecosystems, affecting biodiversity, fisheries and the water resources on which communities depend. For the thousands of families who rely on Chilika's waters for their livelihoods and food security, these ecological changes are translating into growing economic uncertainty and difficult choices about the future, finds a recent study.

Seagrass meadows, cradles of the coasts

Seagrass meadows cover six continents and an area of over 300,000 km² and are one of the most widespread coastal habitats on Earth, providing valuable nursery habitats to over one-fifth of the world’s fisheries by providing protection from predators, rich feeding grounds and stable environments. They improve water quality by filtering, cycling, and storing nutrients and pollutants and reduce the incidence of pathogenic marine bacteria and disease and contamination in seafood.

Additionally, seagrasses provide cultural benefits by supporting tourism and recreational activities while providing nature-based solutions to tackle climate change. Seagrass meadows are highly efficient carbon sinks, storing up to 18 percent of the world’s oceanic carbon, and can also buffer ocean acidification, thus contributing to the resilience of the vulnerable coral reefs, and act as the first line of defense against floods and storms.

Chilika lagoon: A biodiversity hotspot sustained by water

Located along India's eastern coast, Chilika lagoon is a globally significant wetland and a designated Ramsar site. The lagoon supports more than 225 fish species, endangered wildlife such as the Irrawaddy dolphin and the livelihoods of over 200,000 fishers and allied workers.

The lagoon also hosts a rich diversity of seagrasses. Seven documented species occur here:

• Halophila beccarii

• Halophila ovata

• Halophila ovalis

• Halodule pinifolia

• Halodule uninervis

• Ruppia maritima

• Cymodocea serrulata

These underwater meadows have long contributed to the ecological productivity of the lagoon. However, the Chilika has been facing eutrophication, aquaculture intensification, plastic and nutrient pollution, hydrological modification through artificial sea mouths, and climate variability, which are threatening its seagrass meadows, and fishers along the lagoon have noticed a decline in fish catch and worsening environmental conditions.

This recent study titled "Linking vulnerabilities of small-scale fisheries with seagrass health and water quality" by Navya Vikraman Nair, Pradeep Kumar Nayak et al., in Marine Policy explores the impact of climate change and anthropogenic factors on the water quality and health of seagrass meadows in the Chilika lagoon and its implications for small-scale fisheries in the region. To understand these changes, researchers conducted detailed interviews with small-scale fishers, women fishers, youth, traders and allied communities across four ecological sectors of Chilika:

Central Sector: Khatiakudi, Barakula, Khatisahi, Sana Nairi, Khirisahi, Nuapada, Berhampur and Balugaon.

Northern Sector: Nuagaon, Jagannathpur, Sorana, Gopinathpur, Balinasi, Tentulipada and Bhusandpur.

Outer Channel: Mota, Karimpur, Satapada, Alupatana, Jadupur, Brahmapur and Sipakuda.

Southern Sector: R Binchanapali, Samal, Pallibandha, Keshpur, Malud, Prayagiri, Patanasi, Ramalenka, Sabulaya and Purnabandha.

Their responses reveal a complex web of environmental pressures affecting both water quality and seagrass ecosystems.

Eight drivers behind seagrass decline and deteriorating water quality 

People identify eight key drivers that have led to the degradation of seagrass ecosystems and lagoon water quality in the Chilika

• Agricultural runoff

Excessive nutrients from agricultural runoff have led to eutrophication, a process where nutrient enrichment from the agricultural runoff has led to algal growth that forms a thick mat on the surface, preventing light penetration to seagrass meadows, thus restricting photosynthesis, affecting growth of meadows and thus killing animals depending on them for their food. The algal growth gets decomposed by bacteria that use up oxygen in the process, leading to low oxygen levels in the waters, further challenging the survival of seagrass meadows and the animals depending on them. 

• Shrimp aquaculture 

More than 80 percent of marine fishers and boat operators say that shrimp farming has had a negative impact on seagrass health and fish found in the waters. Habitat destruction due to expansion, increased turbidity, salinity due to wastewater discharges from the aquaculture industry, and nutrient overload leading to algal blooms and lack of oxygen content in the water due to chemicals from the aquaculture industry have led to deterioration in water quality and affected the seagrass meadows negatively.

• Tourism and associated waste 

Tourism-intensive areas such as Satapada and Rambha are found to be negatively affected due to plastic waste, bottles, food, and wrappers during the tourist season. Seagrass meadows often get entangled with plastic, leading to turbid waters and shoreline debris accumulation. Boat activity is also found to physically damage seagrass meadows. 

Local fisherfolk talk of the impact of pollutants, including plastic waste, untreated sewage, and chemicals from shrimp farms and cultural runoff on seagrass and fisheries. They frequently report “catching more plastic than fish” and note that “plastic waste, like bottles and bags, floats everywhere in the lagoon”.

The presence of oil slicks from motorboats and waste left behind by tourists further exacerbates the pollution problem and also affects the survival of seagrasses. As one respondent says, “Tourists bring money but also leave behind garbage," highlighting the dual-edged impact of tourism. Over the years, the lagoon has shifted from a relatively clean and thriving ecosystem to one described as “murky, polluted, and lifeless", directly threatening small-scale fisheries.

• Plastic pollution 

Blocks sunlight preventing photosynthesis. Microplastics are found to accumulate in seagrass ecosystems, degrading water quality while chemical leachates from the plastics harm aquatic organisms.

• Cyclones and storm surges 

Intensify ecological disturbance and amplify existing drivers in the lagoon. The 2019 cyclone Fani had uprooted all the seagrasses and filled fishing grounds with mud. Such events can increase sedimentation and transport organic debris, which, when broken down by microbial decomposers, results in elevated respiration and subsequently lowers dissolved oxygen levels killing seagrasses and polluting waters. 

• Artificial sea mouths 

Periodically opened sea mouths to manage salinity and flushing for hydrological balance can alter hydrology and lead to erosion and habitat fragmentation. Salinity fluctuations affect biodiversity and species diversity and disrupt sediments, increasing turbidity. Artificial sea mouths have disrupted natural water flow, leading to increased sedimentation that buries vital seagrass meadows and fish breeding grounds. As one fisher says, "Now, mud and silt are covering everything because of pollution and construction."

• Illegal fishing practices 

Dragnets uproot seagrass and disturb sediments. Juvenile overfishing reduces ecosystem regeneration. Oil spills and waste from fishing boats pollute the waters, and overfishing changes the aquatic dynamics in the water.

• Climate change

Rising temperatures affect seagrass growth cycles while increased salinity impacts seagrass resilience. Elevated temperatures increase algal bloom frequency, while rising sea levels lead to saltwater intrusion.

What do fishers say about the impact of these changes on seagrass meadows 

The decline of seagrass meadows is visible to those who spend their lives on the lagoon. One respondent says, “Seagrass is disappearing, and we’re seeing fewer fish, making it harder to sustain our families." Fishers remember a time when seagrass meadows provided shelter for young fish and supported abundant fisheries.

They describe them as "a shelter for baby fish" and worry about their continued decline due to pollution, sedimentation and habitat destruction. The uncertainty is reflected in another fisher's concern: "If things keep going like this, we’re afraid we might lose the seagrass for good."

When ecological decline becomes a livelihood crisis

The degradation of water quality and seagrass habitats is directly affecting food security and livelihoods. As fish stocks decline, fishing households face increasing economic hardship. One fisher sums up the situation: "It feels like the lagoon is losing its strength, and we are losing our way of life." Many families are seeking alternative income sources or migrating in search of work"

As one respondent explains: "Some of us have to look for other work or migrate to other places, but we don’t want to leave." The impacts extend to education as well. Some households now rely on children to contribute to fishing activities. One fisher notes: "The young boys in our village have left school to help with fishing." These changes are reshaping community life and weakening long-standing social and cultural connections to the lagoon.

Governance gaps and community concerns

When asked about the need for interventions, fishers say that weather warning and cyclone resilience programmes need to be the top priorities. As a community member highlights, "When we receive warnings early, we can save our nets and boats. It makes a difference." At the same time, initiatives such as mangrove plantations and environmental education programmes receive much lower ratings. A woman fisher says, "I’ve never seen any mangroves planted in our area. Maybe they do it elsewhere, but it’s not helping us here."

Fishers also highlight weak enforcement of regulations. One respondent states, "Rules exist, but no one checks if we follow them." Many community members feel excluded from decision-making processes". As one fisher remarks, "Whenever the government or researchers come to study the lagoon, they don’t involve us much." The findings reveal a significant gap between policy design and community participation.

What can be done to restore Chilika's waters?

Strengthen participatory governance

• Establish village-level fishery committees.

• Promote co-management frameworks that integrate traditional knowledge, local stewardship and scientific monitoring.

Expand environmental education

Fishers expressed a need for clearer scientific understanding of how water quality, seagrass ecosystems and fisheries are interconnected. Education programmes should be developed jointly by ecologists, civil society organisations and elder fishers. Topics should include:

• The ecological role of seagrass and mangroves.

• Impacts of aquaculture and plastic pollution.

• Climate change and lagoon hydrology.

Diversify livelihoods

Alternative livelihood opportunities could include:

• Community-based ecotourism.

• Value-added fish processing.

• Training programmes for women and youth.

• Payment for ecosystem services initiatives.

Scale up ecological restoration

Restoration efforts should focus on:

• Community-led seagrass and mangrove planting.

• Monitoring water quality using affordable tools.

• Protecting critical habitat hotspots.

Improve waste management

Key actions include:

• Establishing decentralised waste collection centres.

• Incentivising the return and recycling of fishing gear and plastics.

• Partnering with recycling and circular economy enterprises.

Restoring water quality is central to securing Chilika's future

The story unfolding in Chilika lagoon is ultimately a story about water. As water quality declines, seagrass meadows disappear. As seagrass meadows disappear, fish populations decline. And as fisheries decline, communities that have depended on the lagoon for generations face growing uncertainty.

The study makes it clear that ecological restoration cannot succeed without local participation. Fishers possess deep knowledge of the lagoon's changing conditions, yet many feel excluded from decisions that affect their future. Bridging this gap through participatory governance, environmental education and community-led restoration will be critical.

Protecting Chilika's waters means protecting the ecosystems, livelihoods and cultures that depend on them. The future of the lagoon will depend not only on restoring seagrass meadows but also on ensuring that local communities become partners in shaping a more resilient and sustainable future.