The waters off Koh Kresna in the Gulf of Thailand now brim with mackerel, sardines, bream, squid, snails, anchovies, crabs and shrimp. “Every day, we are out catching fish and selling them,” says Khiev Sat, the long-time community leader and head of a fishing family. The local fishery is thriving today, but a few decades ago the sea around the island was largely empty.
Worldwide, coastal fisheries have suffered as climate change, pollution and overfishing shrink marine populations while demand for seafood rises. Koh Kresna’s recovery, however, began with restoring one keystone habitat: the mangrove.
Mangroves are salt-tolerant trees and shrubs that grow in waterlogged coastal soils. Their tangled root networks anchor sediments, blunt waves and build complex underwater structure that acts as nursery habitat for juvenile fish, prawns and other invertebrates. A 2024 analysis by governments and biodiversity organizations estimates mangrove roots support roughly 800 billion young fish, prawns and crustaceans each year. As coastal geographer Radhika Bhargava Gajre observes, “The majority of the fishes that we eat are supported by mangroves.”
Beyond nurseries, mangroves protect shorelines from erosion and storm surge; studies show villages shielded by mangroves suffer far fewer deaths in severe cyclones. These forests also store exceptional amounts of carbon: their leaf litter and wood become trapped in waterlogged soils where decomposition is slow, allowing mangroves to sequester up to four times as much carbon as many other forest types.
Yet mangroves face heavy pressure. They are cleared for shrimp ponds and aquaculture, logged for charcoal, removed for coastal development, polluted and stressed by rising seas. The United Nations warns roughly half of mangrove ecosystems could be at risk of collapse by 2050.
Cambodia experienced a severe mangrove loss after the Khmer Rouge era. With the economy crippled, many people cut mangroves for charcoal to survive. Without those forests, juvenile fish had nowhere to shelter, local catches collapsed and villages emptied as people left for factories or emigrated.
Over the past 30 years, scientists and conservation groups have helped spread knowledge about mangroves’ value, and local fishers have acted. Since 2003, Koh Kresna and nearby Lok have cooperated in a community fishery that manages shallow coastal waters, enforces sustainable harvests, protects more than 145 acres of mangrove forest and runs restoration programs. In the last two years residents and fishery members planted over 2,000 mangrove saplings with support from organizations including the Red Cross and Landesa. “It is a lot of work. It takes a lot of cooperation between the fishery members, the government and nongovernmental organizations,” says Rusrann Loeng of Landesa.
Koh Kresna reflects a wider pattern: global mangrove loss slowed after 2000 as restoration increased. A 2023 U.N. analysis found net mangrove loss fell by 44% between 2010 and 2020 compared with the previous decade, and conservationists point to community stewardship as a major reason.
Restoring mangroves delivers more than bigger catches. Their roots reduce erosion and absorb storm energy, lowering flood risk and saving lives as storms intensify. Their soils lock away large amounts of carbon—though mangroves cover only about 0.2% of the world’s forests, they account for roughly 2% of global forest carbon removal, according to the World Resources Institute. “We are helping the whole world,” says 21-year-old fishery member Khiev Chien, linking local work to the global climate.
Koh Kresna shows that rebuilding mangroves can revive livelihoods and provide wider environmental benefits. The effort is labor intensive and requires long-term local commitment plus coordination with governments and NGOs, but the payoffs include healthier fisheries, safer coasts and meaningful carbon storage. Communities like Koh Kresna offer a practical model of how nature-based solutions can restore ecosystems and the people who depend on them.