Sustainable Food Systems: Aquaculture and Aquaponics

September 12, 2024                                                                                                
Authors: Mohamed Nazer

Food Security and the Role of Aquaculture

Food security, the global challenge of ensuring everyone has access to enough safe, nutritious, and affordable food, often gets overlooked. While great progress has been made in sustainable food production, the rising demand for nutritious food means we need to explore other options. One such promising solution is aquaculture, the farming of aquatic organisms.

What is Aquaculture?

Aquaculture involves breeding, raising, and harvesting aquatic creatures like fish, shellfish, and plants in controlled environments to meet the growing demand for seafood. It’s practiced in both freshwater and marine environments, ranging from man-made ponds to coastal waters. This sustainable method helps tackle the problem of overfishing, which is depleting wild fish stocks due to environmental changes. Plus, species like oysters and mussels help clean the water, making aquaculture beneficial for both food production and environmental management.

Diverse Aquaculture Crops

When you think about agriculture livestock, what animals come to mind? Cows, chickens, and pigs, right? Well, aquaculture isn't so limited. In fact, it's incredibly diverse, with about 622 different aquatic species, including finfish, mollusks, crustaceans, and other aquatic invertebrates. This diversity allows for the cultivation of a wide variety of species, each playing a unique role in nutrition, the economy, and the environment. Here are some of the most common species grown in aquaculture:

1. Finfish:

Salmon: Predominantly farmed in Norway and Chile, Atlantic salmon is highly valued for its fast growth and global market demand.

Tilapia: Known as the "aquatic chicken," tilapia is mainly farmed in Asia, Africa, and Latin America, appreciated for its adaptability and high protein content.
Catfish: Extensively farmed in the U.S., especially in Mississippi, catfish are resilient and thrive in various conditions.

Trout: Common in Europe and North America, trout farming requires clean, cold freshwater, thriving in streams and lakes.

2. Shellfish:

Shrimp: Shrimp farming has become a significant component of aquaculture, providing a sustainable source of protein.

Oysters: Farmed globally, oysters are valued for both their delicacy and ecological benefits like water purification.

Mussels and Clams: These bivalves are cultivated for their nutritional value and role in maintaining healthy ecosystems.

3. Aquatic Plants:

Seaweed: Prominently farmed in China, Japan, and Korea for food, pharmaceuticals, and biofuel, seaweed offers environmental benefits such as carbon sequestration.

Microalgae: Cultivated for dietary supplements, animal feed, and biofuel, microalgae are recognized for their high productivity and minimal land use.

4. Other Species:

Crustaceans: Includes crayfish and crabs, providing valuable food sources and economic opportunities, though some species can be invasive.

What is Aquaponics?

Aquaponics is a system that integrates aquaculture (raising aquatic animals) with hydroponics (growing plants in water). This method creates a closed-loop system where fish waste provides essential nutrients for plant growth, and the plants help clean the water, which is recirculated back to the aquaculture tanks. Aquaponics optimizes both water usage and nutrient cycles, making it an environmentally friendly and resource-efficient approach to producing both fish and crops.

Case Study: How Rainbow Trout Wastewater Grew Lush Greens

In 2022, SASRER Lab conducted a pilot study assessing vertical decoupled aquaponic system as a solution for sustainable food production. The study aimed to explore the usage of fish wastewater from rainbow trout as a nutrient content to grow baby lettuce and rocket plants. They evaluated water use efficiency, land use efficiency, and yield. 
The vertical aquaponic system (Figure 1) integrated fish and plants in a two-level greenhouse. Trout swim in tanks below, while above, leafy greens thrive, fed by the fish wastewater in a closed-loop process that optimizes water and nutrient use.

The Solution: A Smart Mix

SASRER Lab tested three nutrient treatments: (1) Fish wastewater, (2) Fish wastewater with added fertilizers (Mix), and (3) a standard nutrient solution (Hoagland, which acted as a control), using two different substrates: peat and perlite. 

Results

1. The Mix–Peat achieved the highest yield for lettuce, at 2,497 g/m², using 38% less water and 10% less fertilizer than the Hoagland control.
2. Rocket plants preformed best In Hoagland treatment, yielding 1,636g/ m².
3. The vertical layout outperformed the single level approach in terms of land utilization, with 7% increase in land use efficiency. 
   Such vertical aquaponic systems provide a year-round, sustainable solution to global food security challenges, positioning aquaculture as a key component in the future of environmentally responsible food production.
   
   

Why Should We Care?

As the global population grows and natural resources become increasingly strained, aquaculture offers tangible benefits that make it a solution we can’t afford to ignore:

Reduces Pressure on Wild Fish Stocks: By cultivating seafood in controlled environments, aquaculture helps alleviate overfishing and protects marine ecosystems.
Minimizes Environmental Impact: Aquaculture systems are designed to reuse water and nutrients, significantly reducing their environmental footprint compared to traditional farming methods.
Provides a Consistent Food Supply: This method ensures a reliable source of nutritious seafood, meeting the increasing global demand for high-quality food.
Optimizes Resource Use: Innovative systems, like SASRER’s, cut water consumption by up to 38% and lower fertilizer usage while maintaining high productivity.

By supporting and investing in aquaculture, we’re not just addressing today’s challenges—we're actively shaping a future where generations can rely on healthy, environmentally responsible sources of food.