Closed System Aquaculture (CSA) is defined as:
“Any system of fish production that creates a controlled interface between the culture (fish) and the natural environment.” 1
Closed containment is a proven, viable technology, and is currently used to raise species such as tilapia, trout and salmon in Canada, the US and China. Whether sited on water or land, closed containment systems can:
- eliminate or significantly reduce water column pollution from feed, feces and chemical waste and contamination of the seabed under farms;
- eliminate escapes from the rearing facility;
- eliminate marine mammal deaths due to interactions with farmed fish and nets;
- eliminate or greatly reduce the risk of disease and parasite transfer to wild salmon; and
- significantly reduce the need for antibiotics and chemical treatments in raising fish.
Because of these advantages, as well as advances in the technology itself over the last several years, closed containment has become widely regarded by scientists, conservationists, some salmon farming companies and the public as a more responsible alternative to net-cage aquaculture. Unfortunately, only a small percentage of salmon is currently farmed in closed containment due to industry’s overall resistance to change and the profitability of externalizing costs. Externalized costs are currently borne by society or the environment and not by salmon producers, such as ‘free’ waste disposal from open net-cage farms into the marine environment.
Closed containment technology not only enables salmon farming companies to be better, more responsible corporate citizens by minimizing or eliminating externalized impacts, it also eliminates or reduces costly problems inherent to net-cages. For instance, closed containment provides protection against the loss of fish through mass escape events or algae and plankton blooms that can kill farmed fish by the thousands as well as protection from sea lice infestations and disease.
By being able to control the temperature all year round, reduce and potentially eliminate diseases and parasites, control oxygen and carbon dioxide, the fish can grow to harvest size six months sooner than it takes in an ocean net pen. Almost all the water needed to grow the fish will be treated and reused with recirculation rates as high as 99%.
More on Closed Containment Technology:
» Economic Case for Closed Containment Technology
» Containment Technology
» Closed Containment & Energy Consumption
» Closed Containment in BC
» Examples of Closed Systems
» Closed Containment Q&A
» Castrophic Events
» Blog Post on Closed Containment Salmon on the Market
1 Global Assessment of Closed System Aquaculture. Prepared for Georgia Strait Alliance and the David Suzuki Foundation on behalf of CAAR.