Go, fish

Innovations in aquaculture:


In the 2015 movie The Martian, an astronaut stranded on Mars is forced by necessity to grow his own food.

The potato crop doesn’t work out so well for Nick Watney, played by Matt Damon in the movie, but Dr. Nick Savidov believes growing food on Mars is quite possible. The bigger opportunity, however, is to grow food here on earth in a sustainable system with virtually no waste.

“Mars is probably the extreme case but we are the same on this planet too. In a way, our planet is a space ship. We don’t have anything coming from outside.”

Savidov is an expert in aquaponics and has created a zero-waste food production system at Lethbridge College, where he is a senior researcher.

The scientist has studied aquaponics for years in previous roles with Alberta Agriculture and has degrees in plant physiology from the Russian State Agricultural University in Moscow and Ben-Gurion University in Israel.

He has developed a system that produces vegetables fertilized with fish waste, which is made possible by beneficial bacteria and micro-organisms that aid in waste breakdown and make nutrients readily available to plants.

Vegetables and fish are both harvested, furnishing nutritious food for people.

“We have what we call an ecosystem. So we have components that allow these fish to coexist in high densities with plants, with bacteria.

“What I’m also trying to stress is that it’s more about … water treatment than about fish and plant production. Because we know how to produce plants. We know how to produce fish. But what we don’t know is how we can make both productions more sustainable.”

Savidov says an integrated production system such as this “closes the loop” of food production, so the waste from one component furnishes food for another component. In the case of aquaponics, the role of micro-organisms is as important as any other part of the system.

“I think this is the future of all agriculture,” says Savidov.

“In aquaponics we culture all three components. We culture animals, we culture plants and we culture micro-organisms, because micro-organisms are as essential, one of the most essential parts of sustainable food production systems.

“If we want agriculture to be sustainable, we cannot ignore the power of micro-organisms. We cannot ignore their role in the biosphere. We’re utilizing their ability to link together animal and plant…. We’re utilizing their ability to convert animal waste into feedstock for plants. That’s one of the major roles of micro-organisms.”

Aquaponics is more than simply adding fish to an existing hydroponics operation. It’s a bit more complicated than that.

At its essence, fish provide a source of nutrients for micro-organisms, which convert the organic fish waste and toxic compounds into soluble nutrients. Those are used by plants, which use the soluble salts for growth while regenerating the water for fish production.

The lobby of the aquaponics building at Lethbridge College has a small-scale working model. Inside, Savidov’s innovations in aerobic biodigestion, full automation and an efficient oxygenation system are at work in a larger scale project, the largest of its kind in the world.

It is designed to develop a system for commercial aquaponics, create consumer acceptance for products produced through aquaponics, prove the economics and provide support for new aquaponics ventures.

There are commercial scale systems in operation in Canada but Savidov sees great potential for wider scale use, both commercially and at a community level.

A closed-loop system could work in Canada’s northern regions, for example, and provide vegetables and fish year round.

“It will allow communities to survive all year, eating fresh vegetables. This is food security and better human nutrition, human health,” said Savidov.

Fish like these tilapia provide a source of nutrients for micro-organisms, which convert the organic fish waste and toxic compounds into soluble nutrients. Those are used by plants, which use the soluble salts for growth while regenerating the water for fish production. | Getty image

Fish like these tilapia provide a source of nutrients for micro-organisms, which convert the organic fish waste and toxic compounds into soluble nutrients. Those are used by plants, which use the soluble salts for growth while regenerating the water for fish production. | Getty image

The Lethbridge College operation uses tilapia as its chosen fish and at the time of a recent visit, a robust bok choy crop was growing in the water flowing through the system.

“What if I tell you that this plant has five or 10 times less nutrients than we use in hydroponics,” said Savidov as he lifted some plants to show off the roots.

“And they grow as well as in hydroponics. Can you imagine the savings? The reason they’re so efficient … is because they have this symbiotic relationship with bacteria and other micro-organisms.”

The relationship is made possible in part by filters with highly developed surface areas. This is where bacteria and other micro-organisms populate and convert toxic compounds into plant fertilizers.

The plants themselves also provide large surface areas on their roots for beneficial micro-organisms to thrive.

Healthy microflora protects both plants and animals from pathogens, says Savidov, in much the same way that probiotics protect humans.

“We’ve started coming to this understanding that not all bacteria are bad. If you take the whole diversity of bacterial species on this plant, pathogenic bacteria would be probably .001 percent. But because of this tiny portion of pathogenic bacteria, we chose to kill everything. And that was our mistake. We can use bacteria and other micro-organisms to protect us from pathogens.”

Oxygenation rather than simple aeration is another key to successful aquaponics. Savidov has developed what he says is a simple design that increases oxygen levels in the water used by the fish and by aerobic microflora.

He has also developed a solid waste loop that mineralizes that material and releases its various minerals so they can be readily used by plants.

“Many aquaponics enterprises fail because they didn’t know how to handle waste,” says Savidov.

Though hydroponic systems can produce plants almost from day one, aquaponic systems need time to mature so the fish, plant and microorganisms establish the needed symbiotic relationships.

“This technology is future. It’s future for us, for this planet. It’s future for our coming generations. It’s future because if we don’t produce food sustainably, we’re not going to survive in the longer term.”

Hydroponics: the process of growing plants in sand, gravel or liquid, without soil.

Aquaculture: the rearing of aquatic animals or cultivation of aquatic plants for food.

Aquaponics: a system of aquaculture in which waste produced by farmed fish supplies nutrients for plants grown hydroponically, which in turn purify the water.

Innovations in aquaculture:

  • more efficient filtration and method of supplying oxygen
  • addition of second loop to convert solid waste into plant nutrients
  • creating more favourable conditions for microbial cultures
  • automation and computerization

Benefits of aquaponics vs. hydroponics:

  • biological, closed loop system
  • no need for synthetic fertilizers
  • uses beneficial micro-organisms
  • self-regulating ecosystem
  • high water retention and efficient nutrient use
  • less energy consumption
  • high environmental stewardship
  • potential for urban agriculture
  • fewer plant diseases
  • two or more revenue streams

Source: Nick Savidov

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