From Rice To Shrimp. Can Vietnam’s Rice Farms and Aquaculture Survive Climate Change?

Written By rynan technologies

Article written by Jillian Wong - RYNAN Technologies

The Mekong River is saltier than ever. As saltwater intrusion worsens in the Mekong Delta region and paddy fields give way to shrimp farms, will shrimps survive the impacts of climate change in the long run? Can we have our bowl of rice with shrimp and eat it too?

RYNAN Aquaculture - Mekong Delta

Flowing almost 3,000 miles from the Tibetan plateau down to the South China Sea, the Mekong River boosts a rich biodiversity comparable to that of the Amazon. It is also one of the most intensively cultivated areas in Asia, supporting the livelihoods of tens of millions of people. 

Rice farming plays an important role in Vietnam’s economy, with the Mekong Delta producing more than half of Vietnam’s total rice production. As the world’s third-largest rice exporter, Vietnam’s rice farming has come a long way, until recent years when saltwater intrusion is threatening rice crops. The Mekong Delta, known as the “rice bowl of the nation”, now seems to be in danger of depleting. 

 
RYNAN Aquaculture - Farmer planting rice on paddy fields

An Appetite for More Diverse Diets

Back in the 1970s, the Vietnamese government invested heavily in reclamation, irrigation, and soil improvement to promote the intensification of rice production. Their efforts paid off, as the paddy fields that sprawled Mekong Delta’s agricultural land increased from 2 to 4.3 million hectares in 2016, catapulting Vietnam into a key rice exporter. The exponential growth enabled the nation to be self-sufficient in food production, but rice farmers were locked into producing low-quality rice with poor returns as they sold their harvest to the state at meager prices. 

As consumer tastes gradually shift to favor higher-quality rice and more diverse diets, many rice farmers are turning to fruits, fish, or shrimp farming which offer better income. 

 
RYNAN Aquaculture - Beautiful view of mekong river

The Mekong is Entering Uncharted Waters & Rice Crops are Withering

Few places on Earth face the wrath of climate change as much as the Mekong delta. 

During the dry season, seawater flows into the Mekong River yearly as part of the natural cycle. Then in the wet season, monsoon rains carry nutrients and silt from upstream to nourish vast paddy fields. As the Mekong floods, salt is flushed through the delta and back into the sea. This annual flooding helps reset the delta’s natural balance and limits saline intrusion. 

However, as sea levels rise, salt-laden water encroaches deeper inland and into the estuaries during the dry season. The Mekong Delta lies on average a meter above sea level, thus a sea-level rise of 0.7 to 1.0 meters could flood approximately 40% of the delta. Rice crops, in particular, are extremely salt-intolerant, and flooded fields can hamper rice planting efforts. With seawater levels increasing along the delta’s shores causing the river to become saltier each year, many rice fields have been destroyed. This climate crisis is also pushing rice farmers away from rice production. 

The construction of several hydropower dams upstream is also causing further stress to the river by reducing freshwater flow and transporting lesser nutrients and sediment during the monsoon floods. If sea levels continue to rise, more devastating floods will follow, with increasingly salty waters that not only damage crops but harm the biodiversity of the Mekong and the livelihoods of those who depend on it. It is estimated that up to 70% of the Mekong’s agricultural land is at the mercy of saline intrusion this century. 

 

Farmers Find A Sliver of Hope in Shrimps

As saltwater intrusion threatens to get more severe in many areas of the Mekong, the environment becomes increasingly unsuitable for growing rice crops. Farmers are switching to products that have a greater tolerance for saline conditions, and shrimps seem an obvious choice. The two most commonly farmed shrimp, L. vannamei, and P. monodon can survive salinities of up to 40 ppt. 


Besides, raising shrimp fetches a profit potential that is 12 times higher than farming rice. Revenue from shrimp exports has surpassed that of rice in Vietnam and has been growing expeditiously since 2013. To further boost the country’s seafood industry, the government has set a goal to double shrimp exports to US$10 billion by 2025 and rolled out training and soft financing to farmers. Caught between rice crops dying from salt intrusion and a glimmer of ‘shrimp hope’ that might extricate them from poverty, rice farmers are making a dive for shrimp rearing. Learn more about the rise of shrimp aquaculture by clicking here.

 
 
RYNAN Aquaculture - Selling shrimps
 

Shrimp Business: A Boon or A Bane?

As farmers ditch rice farming for the more lucrative business of shrimp rearing, paddy fields are either abandoned or converted into shrimp farms. Intensification of aquaculture development has also led to the destruction of mangroves, rendering the forests defenseless against flooding, erosion, and salt intrusion. At present, shrimp aquaculture is posing a host of other environmental problems. Antibiotics, chemicals, and contaminated wastewater from shrimp farms are released directly into surrounding waters, further polluting an already ailing river and seriously damaging its biodiversity. When the Mekong reaches a state of irreversible contamination, farmed shrimps that were meant to save the day will eventually meet the same fate as the rice crops.

Reviving The Rice Fields and Saving The Shrimps 

It seems a feat to reverse the catastrophic impacts of climate change on the Mekong. Furthermore, the compounded effects from agricultural activities on the Mekong and the consequences from hydropower development will have a serious impact on global food security for those depending on the river for sustenance and livelihoods. 

Climate change isn’t going away, and the only way to guarantee a full rice bowl is to develop sustainably in both aspects of shrimp and rice - the two main products that will bring high turnover export and food security. 

Mixed rice-shrimp aquaculture ponds look promising as a solution to mitigate the effects of climate change and promote the sustainable production of both rice and shrimp. Traditional methods cultivate rice and shrimp separately, and we’ve seen its dire consequences. With mixed rice-shrimp aquaculture, these ponds produce rice and fresh-water shrimps in rainy seasons and rear brackish-water shrimps during dry seasons and in periods of saltwater intrusion. Ponds are fertilized naturally by shrimp manure and nutrient-rich sediment from flood waters during the monsoon season. This method restores the natural sedimentation process and minimizes chemical use in pond treatment. Clean river water will be supplied through intake channels, while wastewater will be discharged through other channels. 

Mixed rice-shrimp aquaculture not only brings economic value and increased productivity to the table, but it also contributes to the preservation of the natural environment. 

After all, for farmers in the Mekong, a meal is never complete without rice. Even better when it is accompanied by succulent shrimps that are farmed sustainably. 

If you are interested in what RYNAN Aquaculture does or the future advancements that RYNAN Aquaculture is developing over here, send us a message.

References: 

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