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 offers a promising solution to many of the problems caused by open net-cage farming. In closed containment systems, there is a barrier between the farmed fish and the marine environment. This barrier helps protect the environment and its wild stocks from the wastes, disease, parasites, and other impacts of industrial salmon farming.

Read the 2008 recently released report, Thriving Economies, Healthy Oceans, a summary of a Global Assessment of Closed System Aquaculture (summary pdf), (80 page pdf).




In an effort to mitigate the devastating impacts of current salmon farming practices, the BC government’s Special Committee on Sustainable Aquaculture delivered a report in 2007 with a list of recommendations. One of the Committee’s key recommendations was that “a rapid, phased transition to ocean-based closed containment begin immediately,” and that the industry transition to closed containment within 5 years.²

CAAR supports the move to closed-containment systems for salmon aquaculture in BC. However, five years might be too late to protect important salmon runs like the wild pink salmon in the Broughton Archipelago. According to a recent study published in the journal Science, sea lice originating at open net-cage farms pose the threat of localized extinction of wild pinks within four years.³

Based on the results of initial trials and of reviews of similar closed system technology, closed containment in BC should eliminate:

• solid waste to the marine environment
• contamination of the area under the tanks
• escapes from the rearing facility
• marine mammal deaths due to interactions with farmed fish and nets

Closed systems will help control:

• disease and parasite (e.g. sea lice) transfer between wild and farmed fish
• detrimental effects on farmed fish from algae blooms

Closed systems may also significantly reduce:

• water column pollution
• feed waste
• the need for antibiotics and chemical treatments of the fish

Containment Technology

Closed system aquaculture includes a wide range of technologies, each with varying levels of separation between the farmed fish and the marine environment. Technologies span from simple barriers to prevent fish escapes to systems that fully recapture and treat waste as well as recycle rearing water. The two most common types of closed containment are:

• solid walled tanks floating in water
• land-based systems such as tanks or lined ponds

The systems showing the most promise for economic viability and meeting required protection of wild salmon are currently floating systems with solid walls. These systems offer a very high levels of solid waste collection and a regular exchange of the tank water with new sea water. Future refinements could include treatment of discharged water. As the technology is tested and proven, incremental improvements in waste treatment are likely.

Currently in BC, there are two ocean-based floating CSA projects under development. Both projects are designed to collect the vast majority of solid waste, control intake water to limit disease and pathogens, and still exchange overflow water with the marine environment.

Around the world, various types of closed tank technologies are used to grow many types of seafood on a commercial scale including:

• arctic char
• trout
• barramundi
• tilapia
• halibut
• turbot
• salmon (in freshwater closed tanks)

For a better understanding of current closed containment technologies, see our recently released, Thriving Economies, Healthy Oceans, a summary of a Global Assessment of Closed System Aquaculture. (summary pdf)

The full report, produced by the Georgia Strait Alliance and the David Suzuki Foundation on behalf of CAAR, is available at Global Assessment of Closed System Aquaculture. (80 page pdf)

See four examples of current closed containment technology.

Closed Containment in BC

In 2007, a proposed commercial scale project for a closed containment salmon facility got underway in Middle Bay, BC, just north of Campbell River.

Agrimarine Industries, which has previous experience with raising salmon using closed containment technology on land, partnered with the Middle Bay Sustainable Aquaculture Institute to build and operate a floating, ocean-based closed containment salmon farm.

The Middle Bay Project will farm local Chinook salmon (known to be resistant to sea lice), and collect and compost the solid waste generated by the fish.

The several million dollars in funds raised came from private investors, charitable foundations, and a $2.4 million grant from Sustainable Development Technology Canada.

“The large B.C. salmon farming companies are going to be
watching this pilot project closely. They’re watching it,
they’re going to be the beneficiaries.
We have to prove to them it’s economic, that’s part of our goal.”

---John Moonen, Board Member, Middle Bay Sustainable Aquaculture

What You Can Do

Send a Fax to the BC Government asking them to fund closed containment in BC!