Aquaculture is the rearing of aquatic animals, most often fish and shellfish, for human consumption. Traditionally aquaculture has been practiced in net-enclosed spaces in lakes, rivers, and the ocean. More recently, Aquaculture has transitioned to tank-based systems that can be constructed anywhere. Hydroponics is soilless growing systems that eliminate the need for pesticides, reduces nutrient pollution, grows produce faster, and allows control over environmental variables.
Modern Aquaculture System, Photo courtesy of California’s Department of Fish and Wildlife.
Hydroponics System, Courtesy of Ryan Somma, “Leafy Greenhouse”
While both Aquaculture and Hydroponics both demonstrate advanced control of natural systems, both practices have their drawbacks. Intensive aquaculture operations produce great amounts of fish effluent as a waste product. This can total as much as 10% of the volume of the system every day. Hydroponics often utilizes concentrated man-made nutrient solutions and the water must constantly be changed to avoid the build-up of salts. Both practices require frequent monitoring, treatment and work to maintain healthy, productive systems.
However, when these practices are combined, their weaknesses become strengths. Fish effluent makes for a great natural fertilizer. The effluent is pumped into a grow-bed of either floating trays or soilless growing media where the water is filtered of its waste/nutrients by the plant roots, nitrogen-fixing microbes, and red worms. The clean water is then re-circulated back to the tanks. Closed-loop nutrient-cycling, the yielding of two different products in the same space, and less chemical/work inputs place aquaponics a class above both hydroponics and aquaculture.
Aquaponics System, Courtesy of Ryan Griffis, “Growing Power, Milwaukee”