Waste from fish farms valuable commodity
Some years ago, a Canadian company engaged in the production of Atlantic salmon smolt used net pens in a lake formed by an abandoned limestone mine quarry to grow the fish in net pens equipped by a second set of nets mounted underneath the grower nets. These second nets were made of fine meshed netting, and the steep sides allowed any solid waste from the grower nets to roll or slide down the exterior net down to a funnel mounted in the bottom of this “collector net” and into a simple air lift gadget that allowed the waste to be pumped up to a holding tank on shore, where local farmers would come and pick up the waste once a week or so in order to use the waste as fertilizer for their nearby fields.
A similar concept is described by Beth Buczynski of Care2, where she asks “Is Fish Poop The Key to Global Food Security?”;
Drought, genetic modification, energy instability, population growth, war. All of these things have a major impact on the price and accessibility of food. A lack of food security has the biggest impact on poor and remote communities, since resources needed for planting, harvesting, and storing food are even harder to come by. In Nepal and other developing nations, aquaponics, a combination of aquaculture and hydroponic growing, is gathering steam as a possible solution.
Aquaculture is the practice of breeding, rearing and harvesting fish or other sea foods, usually in ponds, rivers, lakes and the ocean, although it can also be accomplished indoors as well. Hydroponics is the practice of growing vegetables in water and nutrients, without soil. Both of these food-producing strategies have been around for many years — just look for the “farm-raised” label on low cost fish — but it’s when they’re combined in a cyclical ecosystem that we start to see their full potential.
Aquaponics is the practice of growing vegetables in water that has been infused with, you guessed it, fish poop. Fed properly, farmed fish excrete valuable nutrients into the water, the water is transferred to the plant growing structure, plants extract the nutrients (which act as natural fertilizer), leaving behind clean water that can be transferred back to the fish. Lather, rinse, repeat. The process produces fish and vegetables without the need for costly fertilizers, says Ram Bhujel, director of the World Aquaculture Society, a not-for-profit global network of aquaculture professionals affiliated with the Asian Institute of Technology, Thailand. It also conserves water and produces protein-rich foods without the costly cultivation of cattle, which could be a game-changer for under-served populations in water-poor countries.
No, aquaponics isn’t a silver bullet. For one thing, there’s the question of power to consider. In remote communities, electricity can be just as scarce as water and fresh food. Of course, depending on size, aquaponics systems only need a relatively small amount of energy, most of which could probably be supplied through solar panels. The point here is that today’s factory farm > grocery store > refrigerator system won’t feed 9 billion people. It’s already failing. We need alternatives, and they need to be cheap, efficient, and easily managed by communities, not corporations. If you don’t mind a little fish poop near your tomatoes, aquaponics is worth investigating before it’s too late.
