Promoting Sustainable Aquaculture in Southeast Asia’s Largest Lake

As his children watch, a man feeds fish in a cage under his home on the Tonle Sap Lake. (© CI/Photo by Adam Keatts)

Feed your family today or conserve for tomorrow? This question illustrates the struggle faced by the 3 million Cambodians dependent on the Tonle Sap Lake’s fishery for daily sustenance.

However, the perceived trade-off faced by people in developing countries — whether to focus on economic development or conservation of natural resources — is often a false choice. Conservation and development should not be mutually exclusive — in fact, they are often interdependent.

There is perhaps no other ecosystem in Cambodia which better illustrates the complex relationship between human populations and ecosystem health than the Tonle Sap Lake. Often coined “the bread basket of Cambodia,” the Tonle Sap is a unique ecosystem that expands dramatically — from 2,500 square kilometers (965 square miles) in the dry season to up to 15,000 square kilometers (5,800 square miles) during the rainy season — creating nutrient-rich breeding grounds for fish and a floodplain which provides year-round irrigation for rice production.

However, there are various forces which threaten the integrity of the Tonle Sap, not least of which is overfishing.

To illustrate this, our team at CI-Cambodia is conducting value chain assessments to identify the dependency that economic sectors have on ecosystem services like fish provision, and the subsequent negative impact that economic activities have on those very services. Through our field analysis, we are determining ways that CI can facilitate change in market systems to reduce the harmful effects on the environment while continuing economic growth.

Here at CI-Cambodia, we hypothesize that a significant driver of overfishing in the Tonle Sap is feed demand from raising carnivorous fish in the rapidly growing aquaculture industry.

As Cambodia’s middle class continues to grow, the national government is increasingly turning to aquaculture development in order to meet the rising demand for fish. It is practiced at various scales throughout the country, from semi-industrial land-based pond systems to small- and medium-sized, cage-based operations on lakes and rivers. Small producers in floating villages on the Tonle Sap are particularly reliant on aquaculture as their primary income source. Unfortunately, rapid expansion of the aquaculture industry has come at a substantial cost to the Tonle Sap’s fisheries upon which so many households depend for their primary protein source.

Fish drying in the sun outside a woman's home along the Tonle Sap River. (© CI/Photo by Adam Keatts)

Cage-based producers primarily raise fish species which require substantial volumes of wild fish as feed. Collectively and unflatteringly referred to as “trash fish,” these small, low value fish are the by-catch of destructive and often illegal fishing gear. Other studies have suggested that up to 30 percent of “trash fish” may be comprised of juveniles, which may have a substantial impact on the breeding cycle in the Tonle Sap.

Currently the impacts of the removal of these fish from their natural environment are not known for sure; however, it is very likely that the large quantities being extracted are leading to a decline in the natural fisheries and an imbalance in the food chain.

Here are just a few of the specific findings:

  • The most common carnivorous and omnivorous species raised in captivity require up to 10 kilograms of wild fish for every 1 kilogram of fish produced — a staggeringly inefficient use of a finite natural resource.
  • Past studies estimate that nearly 60,000 tons of freshwater trash fish are used annually for inland aquaculture feed. This represents 22 percent of the total inland fish catch.
  • In 2010, the Tonle Sap’s total inland aquaculture production was around 50,000 tons; and by 2019, the government aims to produce 180,000 tons of fish per year through aquaculture — revealing the substantial wild inputs that will be required if there is no intervention.

These sobering statistics highlight the need for change in aquaculture practices. In many cases, the species that are being raised must shift to those which require little to no wild fish to thrive.

A woman prepares to trade fish purchased from aquaculture producers and fishermen on the Tonle Sap. (© CI/Photo by Adam Keatts)

We are currently conducting a comprehensive study that will identify which species require wild fish to grow; identify precisely why producers decide how much trash fish to use; and develop solutions for how those decisions can be shifted to a more economically and ecologically efficient alternative. We will work with the government to prioritize the need for robust domestic feed processing and fingerling breeding industries, and identify private sector partners who are committed to long-term investment in the sector.

CI is also working closely with the Cambodian government’s Fisheries Administration and other development partners to articulate clear policies around fisheries management and aquaculture development, and supporting the government to effectively enforce those policies. The government recently displayed their commitment to cracking down on the aquaculture production of illegal fish species such as the giant snakehead (Channa micropeltes) and the illegal fishing gear used on the Tonle Sap.

Our goal is to ensure that livelihoods and food security on the Tonle Sap are not threatened by the enforcement of these very important policies, and that producers can continue to raise fish in a way that meets the growing demand while reducing the impact on wild fish stocks. Our activities are currently in the design stage, with seed funding enabling us to jumpstart the project; however, to make this vision a reality, we are looking to expand this into a fully funded longer-term program.

Adam Keatts

Ultimately we want to expand this concept of sustainable aquaculture to secure critical food supplies for future generations of Cambodians. We hope that once this project is successful, our model of value chain programming with ecosystem service considerations can be adapted to other industries affecting the natural environment.

Adam Keatts is the economic team leader for CI-Cambodia. To hear more about Adam’s work, listen to a recent interview with Practical Action UK through the SEEP Network’s Market Facilitation Initiative.


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