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Sustainable Resource Management Program

Aquaponics

Natural resources have been the foundation of economic development in The Bahamas for hundreds of years. On Eleuthera, agriculture prospered because of a favorable climate and red, lateritic soils that allowed for large-scale production of crops such as pineapple and vegetables. Eleuthera was once the breadbasket of The Bahamas, providing produce and meats to the entire archipelago. Unfortunately, changes in market demands in combination with intensive growing practices reduced the land’s ability to sustain agriculture at a commercial scale. Currently, the future of food security in The Bahamas is in severe jeopardy, especially as the focus of economic development shifts from extractive natural resources and agriculture to tourism. According to recent statistics, if trade ties were ever severed The Bahamas would only be able to feed itself for six weeks. For the health of the nation, it is essential that local food systems be redeveloped so that the islands can be more self-sufficient and prosperous. However, given the prevailing environmental conditions and the lessons learned from past agricultural methods employed in The Bahamas, novel methods of food production that are low-cost, environmentally-friendly, and sustainable need to be used.

Aquaponics, the combination of aquaculture and hydroponics, offers one potential solution to the need for ecological food production in The Bahamas. Unlike hydroponics alone, aquaponics utilizes fish to provide nutrients necessary for plant growth, and in taking up the nutrients, the plants help clean the water used for growing the fish. This method of “closing waste streams”, especially in a recirculating system, virtually eliminates the negative impacts commonly generated by traditional aquaculture. In addition, utilizing dissolved and particulate wastes commonly produced by fish can result in secondary and even tertiary levels of food production beyond those produced by growing fish alone. Unlike conventional agriculture, there is no dependency on synthetic, commercially-produced, and often expensive fertilizers, nor is there any requirement for soil as a growth media; all traits that make aquaponics a favorable alternative method for food production in areas where imports are expensive and fertile soil scarce.

The goal of the aquaponics project at the Cape Eleuthera Institute is to determine the feasibility of aquaponics as a low-cost food production system for the region. By perfecting a model system that can operate at small or large scales, we are aiming to stimulate the use of aquaponics for commercial operations that can also provide income for local communities. Our model system currently utilizes water from rainwater catchments to ensure cost-effectiveness and environmental friendliness. Nile tilapia (Oreochromis niloticus) are raised in inexpensive tanks and grown under ambient temperature and light conditions to help minimize operating costs. A gravity flow system also helps to reduce costs by passively moving nutrient-rich water from the fish tanks, through a settlement tank and biofilter, and ultimately into shallow growbeds. Plants currently under cultivation include herbs such as basil and cilantro, and lettuce greens such as Buttercrunch bibb, Kyona Mizuna, Red Russian kale, Red Giant mustard, and Tatsoi. After flowing through the growbeds, the water enters a collection sump where the systems only pump actively moves the water back into the fish tanks. In conjunction with The Island School, our current focus is determining whether there is a correlation between the spacing of plants in the growbeds and final harvest weights. Future research endeavors include looking into on-site sources of fish feed (such as snails, worms or duckweed), locally available sources of fertilizers, establishing our own tilapia brood stock and experimenting with other plants.