"Freshwater aquaculture production has increased by 167% in Bangladesh between 2001 and 2017, surpassing fish production from natural open water bodies during this period. However, studies have shown that such dramatic growth in agricultural production can alter the earth's potential to generate goods and services in the long run by pushing certain planetary boundaries and disproportionately hurting people who are directly dependent on ecosystem services for livelihoods in the short run and all of mankind in the long run. This research analyzes the growth of freshwater aquaculture in Bangladesh from three perspectives, through three papers. The first paper explores the question of why fish farmers have been motivated to come into aquaculture and expand fish farming. Based on qualitative case studies and focus group discussions in Mymensingh district, a major region of freshwater aquaculture growth in Bangladesh, the study shows that high profitability of aquaculture for more than two decades since the 1990s has motivated people to engage in fish farming. The second paper builds a system dynamics model of land conversion from crop production to aquaculture that simulates future trends in land conversion and food production. The objective of this study is to analyze the dynamics of crop land conversion to aquaculture over time, and understand what key variables are influencing the transformation process. The model is parameterized at two geographical scales: for the entire country and for Mymensingh district. The results show that fish yield, prices, and concentration of supporting industries are some of the key factors that are influencing the growth of aquaculture. This study also observed that although rice land is being converted for aquaculture and other purposes, there is no imminent threat from aquaculture to rice production, as the decline in rice land is being off-set by the growth in rice yields over the last few decades. The third paper embeds water use models in the land use change system dynamics model built in the second paper, in order to understand whether aquaculture growth in Bangladesh is changing water productivity by substituting for irrigated rice production, and how aquaculture growth is impacting groundwater use quantity. The results show that water productivity combining both rice and fish production is generally increasing, both in the case of Mymensingh, and Bangladesh. However, the total volume of water use combining both rice and fish production is increasing in the high aquaculture concentration region of Mymensingh, but decreasing in the country overall. Overall, the research shows that aquaculture growth in Bangladesh has a positive impact on food supply, but continued success of this growth depends on prices and yields continuing to move in a favorable direction. Also, future development of aquaculture needs to focus on groundwater saving technologies, in order to ensure that groundwater extraction does not exceed safe yields in the long run."--Pages ii-iii.
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