People in Southeast Asia have been farming fish for centuries, and aquaculture is an important industry in Thailand. In 2010, the total yield of aquatic animal products was more than 3 million tons, with approximately 42% coming from freshwater and coastal aquaculture and the rest from wild capture fisheries. As consumer demand for fish increases and harvests from capture fisheries decrease, farmed fish are a growing source of livelihood and food; more than 600,000 people in Thailand are directly or indirectly involved in the industry. Also, because aquaculture cycles continue year round, unlike many planted crops, they can stabilize and increase income for families with access to a river, a reservoir, or land with a good water supply.
Impacts from a changing climate
In recent years, extreme climate events like floods and prolonged dry seasons have been stressing fish farming operations, leading to increased risk for farmers. Despite this, researchers are gaining knowledge about how to sustain farms and perhaps even grow the industry. An IDRC-supported project led by Chiang Mai University is studying the role of aquaculture in a variable and changing climate, and developing adaptation strategies at the farm and river basin level.
In northern Thailand, red tilapia and Nile tilapia are the commercial species of choice; they comprise more than half of the fish fry sold to farmers from 15 government hatcheries in the region. These fish are suited to life in either a net pen placed within a natural river system or reservoir (red tilapia) or a man-made shallow pond – often a converted rice paddy – on farmer's land (Nile tilapia). Fish farmers themselves monitor and observe fish health. One of the barriers facing tilapia farmers is that they have limited scientific information about the fish they grow or the ecosystems they use to grow them. Farmers are not always aware of the best ways to reduce risks from climate variability or to adapt to climate change.
The research team is helping to improve management practices on fish farms by examining factors such as water chemistry, fish farmer decision-making, and government policies. One important example is the need to manage pond water quality so that dissolved oxygen levels do not fall too low at night and leave fish gasping for air. This is a high risk on overcast days for ponds that are “too green” – algae consume a lot of oxygen at night and without sun the following day to support photosynthesis, the oxygen is not replaced.
Need for improved water management
Across Thailand, water management plans take into account irrigation, hydro, flood mitigation, and commercial and domestic uses, but they often do not account for aquaculture. In the case of net pens in highly regulated rivers, fish farm needs are similar to those of natural fish populations and ecosystems, but environmental flows, are not currently a priority. Allocation of water in the dry season to fill ponds is often challenging, given many competing uses. Helping other water users understand aquaculture's stake in integrated water resources management is critical to its sustainability, and is an important policy focus of this research.
Climate variability and change complicate existing water management. The risks of floods and droughts are highly seasonal, and vary substantially from year to year and from decade to decade. Extreme weather and climate events stress fish by directly affecting the water resources and ecosystems that aquaculture depends on. This may lead to poor fish health, disease, or even death – all of which affect a farmer's profits and livelihood security.
Collaboration among key stakeholders is needed to develop appropriate adaptation strategies in response to these uncertain, variable, and changing environmental conditions. The research team is enabling cooperation between local government agencies, departments of fisheries and irrigation, and farmers' groups to help inform and set priorities for action at different levels. The results from this research – ranging from published scientific papers, to recommendations for farmers, to new collaborations and policy priorities – have the potential to make a difference across Southeast Asia.
Photo (right): Chiang Mai University
Red tilapia being raised in a net pen in Northern Thailand.
Jennifer Kingsley is an Ottawa-based writer.