Open Net Industry vs. Closed Containment Fish Farms in BC

by Ruby Berry, Georgia Strait Alliance

If the wild salmon are going to survive, the open net cage farms must get out of the water. If the salmon aquacul­ture industry is to survive, it must get into closed contain­ment.

Most British Columbians are calling for this transition.But what does it mean and how close are we to making it happen?

Only two years ago, government and industry were claiming that growing salmon in tanks was an impossibil­ity and would never happen.

Sales at Overwaitea

But times have changed and we are on the cusp of an enormous shift. Overwaitea Food Group has committed to switching to selling farmed salmon only if it is grown in closed containment. You can now buy salmon grown en­tirely in tanks at their Save-On-Foods stores, at comparable prices to open net cage farmed Atlantics, and the company is still turning a profit. Numerous commercial scale closed system salmon farms are being planned and developed in BC, and Marine Harvest has posted a position for a Project Manager for a closed containment pilot salmon farm. Most noticeably, the conversation has changed from dismissive to problem solving. It’s beginning to feel like a gold rush.

The key to closed system aquacul­ture is control of the interactions between the wild and the farmed. Systems which allow control of water intake, water and waste outputs, and separation from sur­roundings, will reduce and actually elim­inate a number of current problems:

•. No longer will there be the danger to the environ­ment and wild salmon from high levels of disease, sea lice, escapes, fish waste, and marine mammal entanglement.

•. The farms will be protected from increasingly dan­gerous ocean conditions such as algal blooms, storms and possible attack from invasive species, such as in Ireland, where an entire farm was wiped out by jellyfish – twice.

•. There is also virtually no risk of the farm fish con­tracting and spreading disease and parasites, resulting in minimal use of antibiotic or pesticide use.

The one major problem of farming salmon which closed containment does not address is that of feed. As salmon eat other fish, currently the feed is being made from whole fish caught for this purpose, consuming more fish by weight than is produced. This must be addressed if salmon farming in closed containment is to be truly sustainable.

Closed system salmon aquaculture has the potential to develop in some very different ways: from small arti­san farms for the local specialty market to major operations mirroring the current export industry.”

On Land or Sea

Commercial scale closed contained salmon will be grown in tanks on land or in the ocean.

Tanks in the ocean employ flow-through technology, reducing disease and sea lice transfer, by bringing sea wa­ter from depths, and collecting the waste before releasing the water back into the ocean. Land-based systems use either fresh, or brack­ish (combination of fresh and salt) water, likely from wells, upwards of 90% of which is treated and re-circulated. This allows for the optimization of tempera­ture and oxygen levels. The operator can essentially replicate summer for the fish, resulting in healthier, faster growing fish.

Both forms require more sophisticated equipment than open net cage operations, but can be located on the grid, near processing facilities and the labour force. No longer will employees have to live away from home while on shift.

An additional benefit is the opportunity to use the ‘waste’ from the farms to grow other food crops. At the mo­ment an astounding amount of this valuable fertilizer com­ponent is indeed going to waste, and fouling the ocean at the same time. For every pound of fish produced, the waste generated can grow the equivalent of six heads of lettuce. This technology could provide coastal communities with jobs, fish income and fresh vegetables.


We have a wealth of expertise and motivation to ad­dress the few remaining challenges. The only real hurdle remaining is political will. The federal government sup­ports the current open net cage industry financially in a number of ways. This could easily be shifted to support a transition to closed containment technology.

Let your government know that you want this to hap­pen – to protect the wild salmon, the wild marine environ­ment, and the economy and jobs of the coastal communi­ties.

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See www.georgiastrait.org for more information

[From WS Summer 2010]

 

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