Ponds are by far the main aquaculture production system for finfish and crustaceans, responsible for 80 % of the global production volume of these commodities. During the last decades, the contribution from pond aquaculture to the global production of finfish and crustaceans still slightly increased, in spite of the fact that less than 1.8 of peer reviewed literature on aquaculture looked at pond culture. Important advantages of ponds are its self-purifying capacity and the provision of natural food, supplementing formulated feed. Disadvantages are high water use and low productivity. Nevertheless, the fact that pond produced fish is relatively cheap, and does not require high investment in areas with sufficient water availability, explains its importance in putting affordable omnivorous species (e.g. carps, tilapia, pangasius) into the market, contributing to reduction of malnutrition and raising incomes in rural areas in the tropics and sub-tropics.
New developments in water purification and sanitation of nutrient wastes are driving intensification, including intensification of pond aquaculture. On average, intensification reduces the discharge of nutrient from aquaculture per unit production. One complementary solution is to develop local circular food systems, which reduce the overall resource use and hence diminish the degree of intensification needed. In a circular economy, aiming to produce within ecosystem boundaries, more attention should be given to optimizing the self-purifying and natural food production capacities of pond production systems.
Nutritious pond feeds nourish both the farmed species and other pond organisms, like bacteria, plankton and protozoa, to stimulate the pond’s inherent capacity to break down fish wastes and produce natural foods for fish. Nutritious pond feeds have more carbohydrates, which fish only partially digest. Once excreted, the carbohydrates provide energy for bacteria to break down fish wastes and any uneaten feed and release nutrients into the pond. Other organisms metabolize these nutrients to grow and multiply, becoming nutritious food sources for the farmed species and reducing nutrient accumulation in the pond. The high levels of carbohydrates in nutritious pond feeds can be sourced from inexpensive and often locally available ingredients, which reduce feed costs while maintaining or increasing fish production, thereby raising profits. On-farm research in Bangladesh shows that nutritious pond feeds increase tilapia production by stimulating natural food production. In combination with the lower cost of nutritious pond feeds, farm income increased 22 percent as compared to a conventional tilapia feed. Intermediate results from ongoing farm trials in other locations, comparing conventional and nutritious pond feeds revealed similar outcomes, with great promise for small-scale fish farmers across Africa, Latin America and Asia.