WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2023 69 (CONTINUED ON PAGE 70) cropping cycle (a period of approximately one year) were combined with food composition data to estimate the productivity per hectare of energy, protein, and five key micronutrients that are both critical for human health and commonly deficient: calcium, iron, zinc, vitamin A, and vitamin B12. We expressed economic productivity as the annual value of food production (USD/ha), calculated as income received from sales of food produced, plus the imputed value of any self-produced food consumed, minus the variable costs of food production. Nutrient productivity is expressed in annual adult equivalents per hectare (AEs/ ha) for 12 combinations of IAA. AEs are equivalent to the number of adults whose requirements for a specific nutrient could be met from one hectare for a period of one year. We used regression analysis to estimate correlations between production of aquatic and terrestrial foods and economic value and nutrient production. Figure 4 presents the distribution of 721 farms in our sample by farming system, defined in terms of four combinations of aquatic foods and four combinations of terrestrial foods. Among aquatic food combinations, production of only fish is most common (39 percent), followed by fish, prawn, and shrimp (29 percent), fish and prawn (26 percent), and fish and shrimp (8 percent). Among the households in our sample, 96 percent produce some carp species, 83 percent produce un-stocked fish species, 82 percent produce other stocked fish species, and 59 percent produce crustacean species (Figure 4). Fifty-six percent of households do not integrate agriculture into their aquaculture production. Integration of aquatic foods with have increased aquaculture demand in Bangladesh. Aquatic foods are typically nutritious and economically valuable relative to staple foods. To promote enhanced production diversity, land productivity, and nutrient cycling on-farm, a wide variety of integrated aquacultureagriculture (IAA) methods are practiced in Bangladesh. Examples of IAA include growing rice, fish, and crustaceans in the same plot (Figure 2), concurrently or in rotation or growing climbing vegetables on frames built over ponds (Figure 3). To date, however, little attention has been paid to if or how IAA practices enhance productivity of micronutrients by small-holder farmers. This is the motivation of this research, which presents a methodology for measuring the economic productivity and nutrient productivity of farming systems and identifying complementarities and trade-offs between these outcomes. Productivity of IAA Farms in Bangladesh We analyzed data from a representative survey of 721 farms in the seven most important aquaculture producing districts of southern Bangladesh, spanning a wide range of IAA practices. On each farm, detailed production data were collected for a single randomly selected ‘sample parcel’ of land that had been used for aquaculture within the past 12 months, whether or not integrated with terrestrial foods. The sample represents the entire population of aquaculture farms in the seven selected districts. Data on the production of 35 aquatic and 31 terrestrial foods harvested from these farms over the most recently completed FIGURE 2. Women transplanting rice in the raised central portion of a gher also used for fish and giant freshwater prawn cultivation. Photo credit: Md. Mahfujul Haque. FIGURE 4. Sample distribution by farming system. FIGURE 3. A farmer harvesting fish from a pond, with climbing vegetables growing on frames visible in the background. Photo credit: Md. Mahfujul Haque.
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