loping nations can combat extreme poverty and hunger. The article provides many statistics on how aquaculture and fisheries are combating poverty and hunger now and how each of the Millennium Development Goals are going to be reached using these techniques. Because of all the way aquaculture is seen to be key tool to bring developing nations out of poverty, I chose to focus on this area for my project.
At present, most of the aquaculture
projects that have been adopted by farmers in Bangladesh are from the Chittagong and Cox Bazar region of Bangladesh. As you can see by the map to the left, these two regions are High risk areas and prone to sea surges during times of cyclones. These sea surges and high winds have particular detrimental affects to fisheries and aquaculture because of the contamination that comes with sea water entering other water bodies and the damaged that is caused to cages and other fishing tools during the storm. A rise in salinity of the water surrounding these fisheries have cause them to be ineffective for growing fish and thus inhibiting the practice of fish farming in these regions. The way Bangladeshi fish farmers deal with this situation at the present is to just move further inland where the water is fresher, but this practice can only last for so long as global warming continue to make sea levels rise.
Current fish farming techniques (article 2) are also quite ineffective and inconvenient because of the need for water and either a river, lake or reservoir. Fish farmers have to travel daily to feed fish in these locations and theft is has also become a big problem as the fish cages are left unguarded for most of the day and night. As I was considering all the possible ways to improve this situation and combat the effect of cyclones I came across an urban aquaculture model written by Jonathan Woods (article 3). Within this study that he did, he was successfully able to recreate a recirculation system on a small scale that needed very little human interaction to function. I took the idea of this recirculation system and applied it to a Bangladeshi fish farming family and saw that it would solve many of the problems they face. Salinity would not be a factor if the water was contained separately to the water that gets affected by sea surges, theft would be less common with the easy placement ability of tri barrel system and less time in the day would be needed to care for the fish as a result of the system.
This is how the system works, This system mimics natural cycles. The sun (or artificial light) shines into the plant tank, causing aquatic plants and algae to grow These plants and algae flow into the fish tank (or are cut and fed) where herbivorous fish eat them. After digestion, the fish excrete am monia (a sort of urine) and produce feces. These are partially broken down by snails and other invertebrates in the bottom of the fish tank and then pumped into the biofilter tank.
In the biofilter tank, specialized bacteria break down toxic ammonia into fa irly harmless nitrates, which can be taken up by plants. Other bacteria and micro-organisms break down other waste products into forms that plants can use. Particles of waste are trapped by rocks and shells where they are eaten by invertebrates or broken down by other microorganisms. This tank acts like an aquatic compost pile, converting wastes into fertilizer for the plants.
Finally, the fertilized water flows into the plant tank, where it is taken up and converted into plant tissues. Submerged plants and algae add oxygen to the water when the sun shines. Clean water, oxygen, and green plant food flow into the fish tank, completin g the cycle.
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