Nutrition-Sensitive Trade: What Zanzibar’s Dagaa Fishery Reveals About Food and Nutrition Security

A recent study published in the journal of Environmental Research: Food Systems, examines how trade in aquatic foods can contribute to nutrition security across regions, using the dried dagaa (small pelagic fish) fishery in Zanzibar, Tanzania, as a case study. The authors introduce the concept of “nutrition-sensitive trade,” which refers to trade that delivers and balances access to nutrient-dense foods to multiple spatially distant populations, including nutritionally dependent or nutritionally vulnerable groups, without undermining the nutrition security in the communities where food is produced, whether agricultural, coastal, or riparian.

Key Findings

The study finds that Zanzibar’s dagaa trade plays a significant role in supplying affordable protein and micronutrients to both local consumers and vulnerable populations in at least six African countries. 

Key findings include:

• Dagaa trade is embedded in both domestic and regional food systems, with fresh dagaa and blanched-sun-dried dagaa largely consumed locally while dried products, primarily sun-dried dagaa and blanched-sun-dried dagaa are exported.  
• Trade flows are dynamic and shaped by environmental, social, institutional, and economic factors, including changing fish stocks, export demand, processing technology, and permit systems. 
• Seasonal patterns strongly affect food availability: during dry seasons, more dagaa is processed for export, which may reduce domestic access to fresh fish, reshaping consumption patterns and potentially influencing nutritional outcomes

Future Research Agenda

The paper proposes a research agenda to strengthen understanding of nutrition-sensitive trade in aquatic food systems.

1. Research is needed to understand how people consume aquatic foods, especially small fish, across different seasons. This includes who eats them, how much they eat, and how fish contributes to nutrition for vulnerable households.
2. More research should explore how households access aquatic foods through markets, home production, or informal networks, and how cost, seasonality, and food availability influence dietary choices.
3. Research should investigate how trade rules, export permits, and regional policies affect aquatic food trade, and whether these systems support fair access to nutritious foods while balancing economic goals.

The study highlights the need to include a nutrition-sensitive trade lens in policymaking, showing that aquatic food trade affects both economic outcomes and nutrition security. In Zanzibar, trade-offs are already emerging between exports and local food access, and these may worsen due to tourism growth, climate change, and increased investment in export-oriented fish processing.

The findings stress the importance of understanding how local communities, especially vulnerable populations, rely on fisheries like dagaa for nutrition. Policymakers should consider both domestic dietary needs and the nutritional role of exported fish in importing countries when designing trade policies.

The study also shows that regional frameworks such as the African Continental Free Trade Area could support nutrition-sensitive aquatic food trade by improving cooperation across countries, reducing permit costs, and harmonizing regulations. Overall, the research provides a basis for creating policies that balance trade growth with equitable access to nutritious foods.

Read the full article: Nutrition-sensitive trade in island food systems: Zanzibar’s aquatic food trade as a lever for regional nutrient supply (Edith Gondwe et al. 2026). 

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The CGIAR Science Program on Better Diets and Nutrition (BDN) identifies, co-designs, and tests food system solutions that tackle major constraints to delivering sustainable healthy diets and improving nutrition outcomes for people in low and middle-income countries. To learn more about BDN, visit https://www.cgiar.org/cgiar-research-portfolio-2025-2030/better-diets-and-nutrition