Closed Containment Fish Farming

Georgia Strait Alliance fish farm campaigner Michelle Young provides an overview of the technology.

Open net-cage salmon farming is a very controversial industry here on BC’s coast and around the world. On the one hand, demand for seafood is quickly surpassing sustainable limits of our oceans, and we need jobs in tough economic times.

On the other hand, can we justify salmon farming at all costs to the environment? Wild salmon are exposed to parasites and diseases from feed-lot salmon farms, and this has a direct impact on return­ing wild salmon numbers. Then there are faeces, chemical residues and wastes from the farms dropping to the ocean floor, net entanglement of ma­rine mammals, parasites on ground­fish found near the farms, and so on.   

Closed containment is suggested to be the sustainable alternative to open net-cage technology, as it would address most of the negative impacts associated with salmon farming in BC simply by separating the farmed salmon from the marine environment. But is it an attainable option? 

Many people are surprised to learn that there are three closed con­tainment salmon farms operating in BC today. There are many technologi­cal variables in closed containment, and these farms reflect that. The farms vary in size from small to medium scale, from fresh to saltwater, and from land based tanks to pens floating in the ocean. And they are variously raising Chinook, Coho and Sockeye Salmon.  

However, the existing closed containment farms have many things in common. They all are successful in separating the farmed salmon from the marine environment. None of the closed containment farms have problems with sea lice, the parasite that proliferates in feed-lot conditions and afflicts wild salmon, and none of them release untreated waste directly into the ocean. These farms and many other examples from around the world have unequivocally demonstrated that it is possible to grow farmed salmon in closed containment.  

The next step is to take the many technological possibilities and de­velop an economically viable com­mercial scale operation. This is where the accountant in me becomes inter­ested. We know that the initial costs to build a closed containment facility are higher than to build a traditional net-cage fish farm. The industry is obviously resistant to higher fish farm startup costs, given that they are al­ready licensed to use the cheaper open system that they are familiar with. Unfortunately, the open net-cage sys­tem wreaks havoc on the surrounding ecosystems. 

Salmon farmers are quick to tell us that closed containment is not eco­nomically viable. On the surface it does appear that way when you just look at the difference in initial startup costs. But comparing the economics of open net-cage technology to closed containment technologies is much more complicated than simply look­ing at initial start up costs, as we have to consider the full economic picture and the cost savings made possible by a switch to closed containment.  

Let’s consider sea lice. After as­suring us that sea lice were not a prob­lem for wild fish and that they don’t come from the fish farms, the indus­try is now saying that they are manag­ing lice to reduce the impact (which they still deny). Emamectin benzoate (trade-named SLICE) is the preferred treatment for sea lice on salmon farms in BC. This drug is not authorized for general use in Canada, but can only be used as an emergency measure under prescription of a veterinarian. Unfor­tunately its use has become common practice. As it is designed to weaken the shells of crustaceans, this chemo­therapeutant may have an impact on other crustaceans like prawns and crabs. If we could measure the effect on crab and prawn fishers’ wallets, and on the commercial salmon fish­ing, recreational fishing and ecotour­ism industries due to the loss of wild salmon, the additional costs of closed containment seem a small pittance to pay.  

Costs difficult to measure finan­cially, such as the loss of wild salmon or free waste disposal for the fish farmers are currently being external­ized as a burden to other industries, taxpayers, and the marine environ­ment. These externalized costs are also offloaded onto First Nations, in­cluding impacts on their culture and their harvest of traditional food sour-ces. Adoption of closed containment technology would mean the fish farm industry would be paying those ex­ternalized costs themselves, and this would give a more complete economic measure of their true performance.  

Even when you look at it dollar for dollar, without considering these externalized costs, there are tradeoffs that will offset the initial startup cost of closed containment. For example, it costs more to filter the water intake in closed containment to ensure sea lice do not enter the system, but that closed containment salmon farmer would never need to pay for very costly sea lice treatments. It may cost more for closed tanks, but some of these sys­tems can last 30 years or more, where­as nets from open net-cage farms need to be changed every five years. Uncer­tain ocean conditions such as algae blooms are another costly prob­lem for BC’s salmon farmers. These blooms can kill whole farms full of salmon. Closed contain­ment has the potential to eliminate entirely this cost of doing business in open net-cages. 

Energy needs on a closed con­tainment farm are often cited as in­surmountable by the fish farming industry. Pumping the water into the tanks, maintaining water tempera­ture, and water circulation can use considerable energy. Once again there are tradeoffs. As they don’t have the same siting constraints, closed con­tainment fish farms could be located near infrastructure such as roads, fish packing plants and electrical grids. This would eliminate the cost of transporting fish, feed, equipment, and crew great distances to remote farm locations as well as the need for generators. The potential for pairing closed farm facilities with alternative energy sources such as tidal and wind is significant.  

With the returned health of the marine environment, these remote regions could be restored as areas for com­mercial and recreational fishing, ecotourism and food harvesting for local residents and First Nations.  

Closed containment tri­al projects to date in BC have not proven to be economical, but each trial had its lessons, which will result in reduced costs the next time around. Pilot projects have yet to be undertaken at a commercial scale, so we have not yet realized economies of scale. 

The industry and government spend significant amounts of money on research and development tinker­ing with open net-cage technology. This money is wasted on a technology that may never be fully sustainable, and it should instead be put into de­veloping closed containment.  

The time for debating the nega­tive impacts of open net-cage salmon farming on our wild salmon, marine environment and coastal communi­ties is long past. Time is running out for the wild salmon, and we must take immediate action to protect them. Re­moving open net-cage salmon farms from coastal waters will save the wild salmon from the impacts of sea lice proliferating on the farms, and will reduce other impacts to the marine environment. A speedy transition to closed containment may very well save the industry. BC’s fish farmers have the skills and resources to make closed containment an economic real­ity and to become global leaders in in­novative new sustainable technology. That is just what our economy needs right now.


Michelle Young is a Salmon Aquaculture Campaigner with the marine conservation organization, Georgia Strait Alliance. For more information, or to find ways you can help, visit our website at www.Geor­ or email

[From WS June/July 2009]

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