Aquaculture makes a substantial contribution to our food supplies, so it must be done in a way that is sustainable. Specifically, TOF is looking at various closed-system technologies, including re-circulating tanks, raceways, flow-through systems, and inland ponds. These systems are being used for numerous species of fish, shellfish, and aquatic plants. Although the clear benefits (health and otherwise) of closed-system aquaculture systems have been recognized, we also support efforts to avoid the environmental and food safety flaws of open pen aquaculture. We hope to work toward international as well as domestic efforts that can effect positive change.
There are four major approaches to aquaculture seen today: near shore open pens, experimental offshore open pens, and land-based “closed” systems and “ancient” open systems.
- The near shore aquaculture systems have most often been used to raise shellfish, salmon and other carnivorous finfish and, except for shellfish mariculture, are typically seen as the least sustainable and the most environmentally detrimental type of aquaculture. The inherent “open to the ecosystem” design of these systems makes it extremely hard to address the problems of fecal waste, interactions with predators, introduction of non-native/exotic species, excess inputs (food, antibiotics), habitat destruction, and disease transfer. In addition, coastal waters cannot sustain the current practice of moving on down the shoreline following disabling disease outbreaks within the pens. [NB: If we grow mollusks near shore, or dramatically limit near shore open pens in scale and focus on raising herbivores, there is some improvement on sustainability of the aquaculture system. In our view it is worth exploring these limited alternatives.]
- The newer experimental offshore pen aquaculture systems just move these same negative effects out of sight and also add other impacts on the environment, including the larger carbon footprint to manage facilities that are further offshore.
- Land based “closed” systems, commonly referred to as recirculating aquaculture systems (RAS), are receiving more and more attention as a viable long-term sustainable solution to aquaculture, both in the developed and developing world. Small, inexpensive closed systems are being modeled to be used in developing countries while larger, more commercially viable, and expensive options are being created in more developed countries. These systems are self-contained and often allow for effective polyculture approaches to raising animals and vegetables together. They are particularly considered sustainable when they are powered by renewable energy, they ensure nearly 100% reclamation of their water, and they are focused on raising omnivores and herbivores.
- Fish farming is not new; it has been practiced for centuries in many cultures. Ancient Chinese societies fed silkworm feces and nymphs to carp raised in ponds on silkworm farms, Egyptians farmed tilapia as part of their elaborate irrigation technology, and Hawaiians were able to farm a multitude of species such as milkfish, mullet, prawns, and crab (Costa-Pierce, 1987). Archaeologists have also found evidence for aquaculture in Mayan society and in the traditions of some North American nativecommunities (www.enaca.org).
Aquaculture in the News:
Holtz, M. “The next food revolution: fish farming?” 25 Oct 2015. The Christian Science Monitor.
Aquaculture is the fastest-growing food sector in the world. See who is dominating the sector, the promise and peril of the industry, what place aquaculture will have in the 21st century.
White Papers by The Ocean Foundation
The Ocean Foundation is also working in collaboration with partners at the Environmental Law Institute (ELI) and the Harvard Law School’s Emmett Environmental Law and Policy Clinic to clarify and improve how aquaculture is managed in United States federal ocean waters.
Find these resources below and on ELI’s website: