Thanlwin River Estuary – Challenges for Fishing Communities

By Dr. Cherry Aung, MK31 Fellow

Thanlwin River estuary with four tributaries

Thanlwin River estuary with four tributaries

As one of the longest trans-boundary rivers and the only major one that still flows freely without dams in Southeast Asia, the Thanlwin river supports the livelihoods of approximately 10 million people. The river hosts rich fisheries and supports fertile farmland vital to the food security of many ethnic minority communities living along the river banks and beyond. Yet, like most rivers in the world, it is facing multiple pressures from both natural and human causes along its length, which could affect the ecosystem and the livelihoods of thousands of local people who depend upon them.

This is readily apparent in the estuary area, which is the focus of my research. Here, it is crucial to understand how people’s lives in the estuary region are impacted by these changes, which are apparent from changing patterns of erosion and sedimentation and fish stocks now under pressure.

Changes and Challenges in the Thalwin Estuary

The Thalwin River empties into the Andaman Sea in Mon State, Myanmar. Its estuary is composed of four tributaries, namely the Dayebauk, Mawlamyine, Gyine, and Attaran rivers. Most of the communities that live in the estuary area depend on the fishery resources.

For over ten years, local communities have been facing the problem of a decline in fish population in the estuary. This includes a decline in fish diversity, average size, and average catch. The decline can be linked to both natural changes and local fishing practices. Locally, overexploitation through the use of large stationary gillnets enhanced with modern techniques, combined with a surge in offshore fishing have contributed to the decline of brackish fish in the area. Although fishing is banned three months a year and is restrained through limited licensing, the problem of brackish and marine fish decline persists.

Nevertheless, the decline in fish stock is also influenced by an acute sedimentation problem. Local residents have reported negative effects from the construction of the Thanlwin Bridge in 2006. The bridge, which crosses at the center point of the tributaries, has created high sediment accumulation and has been linked to erosion. Due to the high degree of sedimentation in the inner estuary, some fish like Herring and Arius which were previously caught there, are nowadays no longer part of the catches in upstream Gyaing and Attran. In addition, sand mining and extensive erosion also contribute to the degeneration of fishing grounds in the region through their effect on the alteration of the water course.

About a decade ago, the Thanlwin estuary was well known for its fishing industry and produce. People from other parts of Myanmar, and especially the upper regions, migrated to the estuary for work and higher income. Nowadays though, local communities as well as migrants have had to adapt to the shrinking local fishing industry. Due to a recent and ongoing decline in fish resources that had supported the small-scale near-shore fishing industry, many fishers are nowadays pushed to migrate abroad in search of economic opportunity.

Mudflat fishing for local consumption

Mudflat fishing for local consumption

Many villages were lost to erosion and the consequent mudflats it left behind, yet people settled in new places and tried to make the best out of their situation. Local communities are being resourceful and innovative in the face of many of the challenges that threaten them. For instance, some locals have learned to take advantage of the extensive formation of mudflats by resorting to mudflat fishing and the production of other mudflat commercial produce.

Local Fishing Industry Recovery

In an effort to protect and recover the fish stocks that are so important to livelihoods in the Thalwin River estuary, a number of steps are currently being taken. These include:

  1. Regulating the offshore and inner estuarine fisheries: The Department of Fisheries is uncovering illegal fishing activities, regulating mesh and net size, regulating and licensing fishing boats, and implementing and enforcing seasonal restrictions on fishing (e.g. during spawning season).

  2. Providing financial support for offshore fisheries: Some NGOs and micro-finance organizations are supporting fishermen in their ventures into offshore fishing (caused by the decline of inner estuary fishery).

  3. Promoting the conservation of natural resources: Communities are supported by various authorized groups to conserve natural estuarine resources such as mangrove wetlands and mudflats, which serve as the spawning and feeding grounds for a variety of estuarine fish species. Illegal cutting of mangroves is banned, and replanting on new lands and in old forests are promoted.

Direction of the Fellowship Research

Altogether, my fellowship study aims to identify potential threats to the commercial fish stocks and evaluate their socio-economic implications for fishing communities of the Thanlwin River estuary.

Interviewing survey in local fishing communities.

Interviewing survey in local fishing communities.

The research will draw on some recent research techniques and technologies that could support community organization and capacity building and that will enable a more sustainable kind of management in community fisheries. These include digital geospatial mapping that could help in assessing the changes in land cover and watercourse in the estuary as a consequence of erosion and sediment accumulation. In addition, evaluations of the current diversity of available fish stock, its migratory behavior, its population, and its fishing volume will allow a more precise understanding of the real-time condition of the fish stock. At the same time, incorporating an understanding of the views and knowledge of the local communities themselves assists in capacity building and the management of the fisheries resources. These elements constitute an important first step to equip local communities with the knowledge to improve their livelihoods and ensure the sustainability of the estuary’s ecosystem.

Edited by Siri Luther