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Pond polyculture key to food security in rural Zambia: University of Stirling study
January 13, 2023 By Hatchery International staff
Scientists from the University of Stirling’s Institute of Aquaculture and WorldFish published an open-access paper that explored the benefits of pond polyculture intervention for food security in rural parts of Zambia.
The paper is titled, “The role of aquaculture and capture fisheries in meeting food and nutrition security: Testing a nutrition-sensitive pond polyculture intervention in rural Zambia,” and was published in the scientific journal, Foods.
The study found that pond polyculture, or farming multiple species in one system, can serve as a viable supplement to capture fisheries that would be subject to seasonal restrictions, as well as tilapia farming.
“Polyculture of small and large fish species in homestead ponds improves food and nutrition security of households as well as reduces micronutrient deficiencies, especially in pregnant and lactating women and children in the first 1000 days of life. Small fish, consumed whole, including the head, organs and bones, pack a bigger punch in terms of vitamins, minerals and omega-3 fatty acids as compared to the fillet of large fish,” wrote co-author and WorldFish Global Lead for Nutrition and Public Health, Dr. Shakuntala Haraksingh Thilsted.
Most of the small-scale pond systems in Zambia naturally attract large quantities of indigenous small fish species as they swim in and out of the pond inlets and outlets. This presents an opportunity for fish to be “trapped” or for farmers to actively stock them from the wild if they thrive well in ponds.
However, small-scale farmers in Zambia are often encouraged to cultivate tilapia in monoculture systems, removing indigenous small fish species from their ponds. The authors thus aimed to rethink tilapia pond systems in Zambia as multi-species systems (polyculture) rather than single-species systems (monoculture) that would offer a direct source of food for household consumption rather than farming tilapia strictly for markets.
The authors also identified that aquaculture, especially polyculture systems with indigenous small fish species, has the potential to improve the nutrient intake of households during closed fishing seasons. Fisheries management regulations, introduced by the Zambian government to overcome overfishing, ban the capture or sale of wild fish between December and February every year. However, these measures drastically reduce the consumption of fish during these months, leading to lower intakes of key nutrients and essential fatty acids. This is especially pertinent for people living in parts of Zambia where fish is their primary source of animal protein.
“While ponds provide an important supply of fish, polyculture ponds provide a good source of diverse, micronutrient-rich small fish species,” Lead author and doctoral candidate at the University of Stirling, Alexander Kaminski said. “However, the amount of fish from the wild, especially small fish species from the large lakes that are dried, play a more significant role in people’s nutrient intake. Ultimately, any improvements to aquaculture should not be done in isolation without considering the more important role of capture fisheries in providing cheap, micronutrient-rich small fish for vulnerable people.”
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