To Shrimp or Not to Shrimp?
By Savannah Stewart
Vietnam is the 8th largest shrimp exporter in the world. More and more people in the Mekong Delta rely on shrimp aquaculture as their many source of income. The question on my mind when we started this trip was: can shrimp farming be sustainable and eco-friendly? After traveling around the Delta the last few weeks, the answer seems to be “Yes”.
We learned about several farming techniques that reduce the impact of shrimp farming on the environment, while still ensuring the farmers’ livelihoods. This balance between sustainability and profitability must endure to allow people to make the transition to environmentally-sound aquaculture.
Deep in the mangroves of Can Gio, we experienced our first lesson with a shrimp farmer. The farmer uses an integrated mangrove-shrimp system that allowed him to take advantage of the natural ebb and flow of the tide to grow and harvest wild shrimp and fish. A gate controls the flow of water and creatures into or out of the shrimp pond. When the tide comes in, he opens the gate and allows water and young shrimp into the pond. These shrimps grow until it’s time to harvest them. Because the farm lies among the mangroves, he signed a government contract swearing to protect a certain amount of the forest on his land. For this he receives a stipend for each hectare of protected mangrove. In this way, he conserves the integrity of the forest while benefiting from the services mangroves provide to the shrimp (like nutrient cycling, water purification, etc.). This decreases the negative impacts of clearing mangroves for aquaculture and provides a sustainable method for harvesting shrimp.
Another farming system we learned about is alternative shrimp-rice farming. In this method, farmers use the dynamic wet-dry seasonality of the Delta to grow shrimp and rice at the best time of year. During the dry season, when brackish water comes in, the farmers raise shrimp. In the rainy season the fields fill with freshwater, which allows for rice to grow. Depending on the type of shrimp, farmers can get one or two crops of shrimp and one crop of rice. Other aquatic organisms such as freshwater prawn and local fish can be raised in the rainy season. The addition of aquaculture adds augments the farmer’s income as well as diversifies the farm. In a way, the farmer creates a sort of artificial ecosystem that is far more resilient than a monoculture of either rice or shrimp.
While these types of farms occur throughout the Mekong Delta, the movement towards sustainable shrimp farming has a long way to go. On our trek through Vietnam, we tended to visit shrimp farms that embraced the shift towards environmentally sustainable practices. However, the vast majority of shrimp aquaculture in the Delta follows traditional intensive farming methods. This type of shrimping does not incorporate shrimp with any other crop, uses higher amounts of fertilizer and pesticides, and overall has higher production costs. Dr. Tran Ngoc Hai explained that intensive farming also harbors environmental and disease-related issues because of the high density of stocked shrimp and the invasive nature of the operation. This farming method drains the land and results in unsustainable use of natural resources that cannot continue into the future.
While unsustainable practices still exist, the farmers of Vietnam show us that shrimp can be raised sustainably. To achieve this, intensive farming must be phased out in favor of mixed farming methods like those described above. Hopefully, with better education we can create a fully sustainable system of aquaculture in the Mekong Delta that can support both the people and the environment.