Human World

Promising technology for fish farming from Canada

Each time a sexy new system emerges for growing fish, aquaculture rises briefly into the media spotlight. While growing fish in a bathtub doesn’t sound like the most appetizing idea, some Canadians have developed this promising technology for fish farming.

The AgriMarine solid-wall fish containment system. Via CTV News

Okay, it’s not exactly a bathtub. But AgriMarine aquaculture of Canada has developed a novel method for growing salmon in a solid-wall fish containment system. Since fish farming has been subject to criticism on the western Canadian coast for many years, farmers are pursuing solutions to maintain aquaculture acceptably in the region.

Click here to see a video of Agrimarine’s solid-wall fish containment system.

Traditional open-water fish farming contains fish in large net cages. Water flows through the net, bringing in fresh water and carrying away waste. In order to separate fish from a natural water body, aquaculture has relied on inland ponds or indoor systems.

AgriMarine’s technique is the first time a system imbedded in a natural water body has also separated the farmed fish from the water body. This separation reduces the waste received by the natural waters and reduces the chance of fish escaping or diseases being released.

Fish farmers are growing Chinook salmon in the solid-wall fish containment system developed by AgriMarine. Via Wikimedia

Scientists and businesses have repeatedly shown that fish can be grown using a variety of methods. It has remained a challenge, however, to show that complex methods can make a profit. This Canadian system might have found a middle ground. It takes the principles of an expensive indoor system – such as waste removal, oxygen management, and solid containers – and moves them into open water on a larger scale. Costs should be reduced because temperature regulation and elaborate filtration systems will not be necessary. Additionally, a reduced footprint on land keeps rents down and can preserve coastal habitat.

However, pumping waste, transforming it into compost, managing oxygen levels, and keeping fish healthy will not be cheap. The pragmatism of this system does offer some hope of reducing the ecological footprint of farming fish in coastal waters, while still being able to sell them for a profit.

A new technology like this usually invokes the language of sustainable food production. As the video mentions, fish farming has faced focused criticisms in the past as being unsustainable. However, comparing food production systems is not as cut and dried as environmentalists or entrepreneurs can make it seem. Many Americans view fish farming facilities as eyesores and a negative change, but in reality all agriculture changes the landscape; that is the nature of every agricultural system.

However, when we see row crops on the periphery of major cities, we view them positively, even fondly. We create ordinances to maintain green space, and we consider agricultural transformation to be one kind of green space. The perception of fish farms and agricultural fields is quite different, yet both result in the same thing – a major change in the natural ecosystem that was made to produce food. An even more important question is how to compare traditional agriculture crops, such as wheat, beef, or pork, to aquaculture. In this case, we don’t even have similar rearing systems and therefore similar production means.

Traditional intensive net pens in China. Image Credit: James Diana

At minute 1:34 the video shows underwater footage of the seafloor below fish farming cages. Viewers probably see this and then compare the footage to their mental image of what they imagine a pristine tidal zone looks like. This comparison is incorrect and unfair. The relevant comparison is to the waste stream coming out of a beef or chicken feed lot; in America much of that waste floats down the Mississippi River into the Gulf of Mexico where it creates a dead zone the size of New Jersey.

Simple calculations of the area damaged by aquaculture would show that the total area of sediment damage by all cage culture in the world is less than half the area of this one dead zone, and there are dead zones near the river mouths of most of the world’s rivers.

Compared to other meat production and traditional cage designs, this new system could reduce the ecological footprint of the fish consumed. So maybe eating fish out of a bathtub isn’t such a bad idea after all.

Why do Americans dislike fish farming?

EarthSky 22: Dead zone in the Gulf of Mexico (audio)

August 10, 2011
Human World

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Keith Hayse-Gregson & James Diana

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