Aquaculture has been a growing technology, used to address declining wild fish stocks. Aquaculture features both indoor and outdoor systems, used to grow fish and supplement wild stocks, as well as supplying product to the global market. Each year, fish demand increases and it is becoming harder and harder to meet that demand. Countries like Thailand and Vietnam are booming in the aquaculture business, enhancing their economies and providing global exposure. However, even with this advance in technology, there are still several problems with aquaculture in regards to sustainability.
Fish eat and they poop. Their poop is chock full of rich nutrients such as nitrogen and phosphorus. But too much of a good thing can be a problem. As fish continue to excrete waste, their waste is broken down by microbes and allowed to exit the aquaculture system. Usually these nutrients enter the surrounding free environment, but this can lead to eutrophication. Eutrophication is a fancy way of saying “too many nutrients” which has negative impacts on the food web. Alga takes over because of this nutrient boom, in turn outcompeting other species for oxygen in the water. Recirculating aquaculture systems (RAS) reuse the water and filter it, rather than just discarding the water into the environment. However, this leaves those nutrients unused and wasted.
Aquaponics is basically an RAS that grows plants with those extra nutrients. The “ponics” part of the technology actually comes from its close relative Hydroponics, or the growth of plants without soil. The use of plants in the aquaponics system not only eliminated the extra nutrients, but also minimizes water waste. This makes the aquaponics system more sustainable. The plants also increase carbon sustainability as well. Most aquaculture systems require some fossil fuels, whether it is for the boats that monitor the pond cultures, or the pump that moves water through an RAS. While aquaponics still utilizes fossil fuels in the form of electricity, the plants also clean out some of those carbon emissions.
So why aquaponics over aquaculture? Well, if the sustainability impacts are not enough to convince you that aquaponics has a place in the culture world, consider the social sustainability. There are many current efforts to include more of the local citizens in aquaponics operations. Michigan Aquaponics is currently collaborating on several systems in Southeast Michigan. A huge part of the business models are to utilize citizen workmanship to not only build the system, but also maintain its growth. This type of work provides jobs and skills that can be applied elsewhere. Aquaculture is in most part run by large corporations. Even in Alaska, many artisan fishing endeavors are being outcompeted by corporations. Aquaponics hopes to bring some of the success of the culture industry back to the locals.