Land Based Aquaponics the Solution to Troublesome Fish Farms?

by: Sara on 01/04/2018

Today's blog post comes from Adrian Southern, owner/operator of Raincoast Aquaponics and the co-author of The Aquaponic Farmer: A Complete Guide to Builidng and Operating a Commercial Aquaponic System. It is written in response the the video of clouds of bloody water being emitted from Vancouver Island salmon processing plants.

By now, most of us have seen the blood-water videos in our Facebook feeds and on the news. A scuba diver drops beneath the sheltered waters of Browns Bay, video camera in hand, exposing billowing clouds of blood-red water spewing from the end of a discharge pipe. The factory discharge pipe releases treated waste-water from processing hundreds of thousands of Atlantic Salmon, directly into a sensitive marine ecosystem.

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Clip from the video Blood Water: B.C.’s Dirty Salmon Farming Secret shows a bloody red cloud of effluent being emitted into Brown’s Bay.

Fish pens collapsing, diesel spills at fish farms, which later harvest and sell those fish to the public, and the ongoing issues of diseases and sea-lice… its no wonder many First Nations are demanding that open-net fish farms be removed from their territories.  When combined with the growing list of concerns of open net-pen fish farming, the images in this video paint a bleak picture of the current state of aquaculture in BC.

Despite the well-known concerns with open net-pen fish farming, not all aquaculture is bad. It is possible to grow fish, while avoiding the spread of disease, environmental pollution, antibiotics and chemotherapeutants.  Land-based Recirculating Aquaculture Systems (RAS) are a step in the right direction, as the fish are separated by tanks from the environment.  These systems ensure that water they grow in is filtered and cleaned for continual re-use. They enable far greater control over the growing conditions, as well as the resulting fish wastes. The biggest issue with RAS systems is that they are far more expensive to build and operate, and thus, fish farm operators are reluctant to invest in them.

Enter Aquaponics, a hybrid production technique that combines a land-based RAS with a hydroponic system (growing plants in water rather than soil).  

In an aquaponic system, the waste-water leaving the fish tanks is sent through a biological filter, where microbes break down the

ammonia and fish excrement, and then through a hydroponic growing area. In the growing area, plants use the decomposed fish waste as nutrients, effectively cleaning the water for recirculation.  Therefore, rather than polluting the surrounding environment, the fish waste is a nutrient source, and ultimately another revenue stream in the form of quality, year-round, vegetables. Any excess waste can easily be sold as a high-quality (composted) plant food, completing the cycle of nutrient capture and efficient energy consumption.

Because they are living ecosystems, aquaponic systems are inherently organic, and care must be taken not to upset the natural balance of organisms within them. This means that fish health and plant pests/diseases must be managed using methods that are non-toxic to ALL the organisms within the system.  

There is no silver-bullet solution to the problems faced by the aquaculture industry. But, by applying the principles of aquaponics, fish farm operators can dramatically reduce their environmental footprint while extracting greater revenue from an existing waste problem.

To learn more about cold-water aquaponics visit www.raincoastaquaponics.com, and read our book The Aquaponic Farmer from New Society Publishers.

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