The world’s wild fisheries are being depleted at a rate much faster than they can be restocked, so aquaculture, which is being employed to supplement the shrinking supply of wild fish, is the world’s fastest-growing food sector. However aquaculture in some cases aggravates rather than redresses the problems of over fishing. The practice contains much promise but must be better understood and more sustainably employed if it is to offer a true solution to the problems created by industrial scale fishing and farming.

What is aquaculture? As defined by the United Nations Food and Agriculture Organization (FAO), aquaculture is the “farming of aquatic organisms including fish, mollusks, crustaceans and aquatic plants. Farming implies some sort of intervention in the rearing process of organisms to enhance production, which includes stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated.” Aquaculture, the agriculture of oceans, lakes and rivers, is the most diverse of all animal food production sectors. This diversity arises from different methods employed in the farming of aquatic organisms. Aquaculture can be practiced in a wide range of salinities, such as freshwater, brackish, and marine, as well as temperatures, such as cold, temperate, and warm. Aquaculture can also be grouped according to production venue and intensity. Essentially that means the type of facility (ponds, cage culture, raceways, water re-circulating systems) used for farming, and the scale of production from small-scale, rural facilities to large-scale, industrial facilities.

Understanding aquaculture matters because aquaculture has the potential to become a practice that can supplement capture fisheries and contribute to feeding the world’s growing population. In 1970, only about 4 percent of the world’s seafood came from fish farms. Today 30 percent does. By 2030, according to United Nations estimate, less than half of the fish humans consume will come from wild stocks. While farming fish provides an alternative to the depletion of natural resources of fish, there is growing concern about certain practices of fish farming that introduce additional environmental pressures to natural systems. There are four central concerns: disease due to crowding, escape of farmed fish into natural systems, fish waste, and fish meal fed fish. This last concern is the biggest concern: high-value species that consume fish meal for feed. It takes about three pounds of fish oil and fish meal from herring, anchovies and sardines caught in the ocean, for example, to produce one pound of farmed salmon. Intuitively, farming fish should take the pressure off wildlife fisheries; however, in the current realm of intensified industrial aquaculture production, rather than providing the solution, farming fish actually exacerbates the problem.

Growing concern over the sustainability of aquaculture operations has created a paradigm shift, and now new alternative methods of production are being proposed. These alternative ways can help aquaculture move forward to fulfill its promise of supplementing capture fisheries. These alternative methods strive to avoid these problems by raising different species of fish together, by treating fish waste with biological mechanisms and then using it as fertilizer in farm fields, and by transitioning to the use of closed systems with water recirculation. A further hope is to use successful aquaculture projects, by diversifying the traditional farmers’ source of income, to provide long term social and economic benefits to communities.

Aquaculture at Dartmouth

In the summer of 2005, Scott Stokoe, the manager of the Dartmouth Organic Farm, sent out a blitz to recruit an “aquaculture” intern. All I knew about aquaculture at the time was that it was something to do with farming in water. Scott Stokoe saw in it the potential to become and define the Farm’s future. I responded to Scott Stokoe with the motivation to combine two things I really enjoyed: farming and fish. Soon after that Scott and I were meeting to brainstorm ideas and develop projects. It was not until last spring however, due to the necessity of forming a plan, fundraising, and doing research, that I had the opportunity to conduct an independent study aquaculture project to look at methods and practices of aquaculture around the world and gain some hands-on knowledge about the topic.

The aquaculture initiative that we got started last spring at the Farm deals directly with these issues of environmental concern over aquaculture production. The idea to our project is to set up a solar pond system inside the new greenhouse that will absorb solar energy during the day for the growth of aquatic organisms in the water and will release energy at night to heat up the greenhouse. With this model, we can grow fish inside solar ponds for consumption, and store heat in these ponds to work as furnaces; substituting solar energy for oil to heat the greenhouse. The organisms growing inside the solar ponds are the main source of feed for the fish. Therefore solar energy takes care of the two high-cost inputs. Furthermore, the fish waste that accumulates inside the ponds can be treated to serve as fertilizers for the plants grown inside the greenhouse, linking two systems of food production to achieve a system mimicking natural systems. Biological filtration of wastes takes care of the problem of dealing with the outputs from the aquaculture system giving rise to an innovative and sustainable method of aquaculture in the context of our new greenhouse.

This is a really exciting time at the Farm as we get ready to move ahead into a new future with the newly acquired farmhouse and the greenhouse. The Farm needs people to bring these ideas to life. Last spring, through my independent study we acquired two fiber glass tanks (solar ponds), but we need more tanks (more money) to get the system working. Most importantly, we need you. We need people who are willing to take the opportunities that our elite, liberal arts college provides to come up with real solutions to real world problems, and we have a real life laboratory (aka the Farm) to test the knowledge that we gain in the classroom in a real life system. Come out to the Farm, play with some fish and get your hands wet!