Closed Containment
Open net-cage salmon farming has many negative environmental implications, primarily because there is no physical separation between farms and the marine environment. Many have called for immediate precautionary farm fallows along BC’s wild salmon migration routes (see Simon Fraser University’s 2009 Think Tank and the Coastal Alliance for Aquaculture Reform’s Wild Salmon Narrows campaign). Fallowing farms is the easiest way to protect wild salmon and the ecosystems they occupy. Watershed Watch is not “anti-aquaculture”, once open-net cage farms are fallowed, closed-containment technology may be suitable to supply our fish needs in a less harmful manner.
Closed containment farming separates farm fish from marine ecosystems with a physical barrier or wall and includes mechanisms to limit external impacts on the environment. Closed containment may be a long-term solution to many of the environmental impacts of today’s aquaculture industry. Numerous groups and government appointed bodies have recognized the growing wave of potential this technology holds. In 2007, The BC government’s Special Committee on Sustainable Aquaculture recommended that a rapid and phased transition to closed-containment begin immediately. In addition, the Pacific Salmon Forum 2009 final report recommended that a commercial-scale closed containment project be initiated.
Closed containment technology has a number environmental advantages over its out-dated predecessor:
- elimination or reduction of disease and parasite transfer to wild fish;
- collection and treatment of solid waste and nutrient discharge;
- reduction in the use of chemicals and other pollutants; and
- elimination of marine bird and mammal entanglements and death.
Many types of closed containment aquaculture technologies exist world-wide to grow a variety of different species in Canada, China and the USA. More recently, closed containment initiatives are beginning to move forward in Chile. As the methods advance, two primary modes of this technology are being used: recirculation aquaculture systems and ocean-based systems.
Recirculation aquaculture systems are primarily located on land and are the most commonly used form of closed containment technology. This method is widely used in fish hatcheries. The bulk of the water is filtered, used and recirculated. The water is typically oxygenated and filtered using microbes to remove waste and excess nutrients.
Ocean-based systems are typically located in sheltered inlets and the fish are raised in large floating tanks. Water is drawn from the ocean and can be treated, filtered and oxygenated. Solid wastes such as feces and feed are collected and can also be treated and used for fertilizer or compost.
Watershed Watch along with Simon Fraser University are working towards shifting open net-cage farming towards a more responsible form of aquaculture technology through public meetings and dialogue among experts. We support the Speaking for the Salmon series through representation on the steering committee, moderating discussions and logistical support.
- Land Based Closed Containment Salmon Aquaculture Workshop, April 26th -27th 2010
- Encouraging Innovative Solutions for Salmon Aquaculture, November 29, 2007
Watershed Watch is a founding member of the Coastal Alliance for Aquaculture Reform (CAAR) and worked with the coalition on countless initiatives for over 10 years. As part of CAAR, we worked with the aquaculture industry on collaborative research and explorations of the viability of closed containment farming systems. We also support the SOS Marine Conservation Foundation in their efforts to resolve the problems of open net-cage farming through technological innovation such as closed containment.
