Aquaculture was developed as a more sustainable way to raise fish for food. Since its development several issues concerning aquaculture have come about. One main problem is the bioaccumulation of compounds and elements such as magnesium, ammonia, and iron in these fish farms.
IPM is a program that has swept all of agriculture, including aquaculture. One IPM method in aquaculture is that of aquaponics. Aquaponics is the practice of hydroponically growing plants and rearing fish together in recirculating systems (Harmon). This cuts down on the fertilizer necessary for plants because the fish waste, when broken down, provides nutrients for the plants. The plants help by removing substances such as ammonia, phosphorous, and nitrate-nitrogen from the water, which can be harmful to the water quality for the fish. On top of the nutrition and cleaning benefits, this greatly reduces the space used, since it is acceptable to grow plants for human consumption on this system.
The plant, however, doesn’t always have to be to human consumption. It some cases, after the plants absorb nutrients they become food for the fish. This is apparent in integrated systems with tilapia and duckweed. Duck weed is a very small, fast growing aquatic plant with no leaf or stem structure that grows in thick mats on the water surface in ponds or streams with high organic matter (AquaSol).
Duckweed is introduced into the recirculating tilapia systems where it very efficiently absorbs excess nutrients, such as ammonia, zinc, and chlorine. If the system is designed properly, duckweed can absorb as much as 99% of these nutrients and dissolved solids (Aquasol). As the duckweed absorbs nutrients and gains in size, it is consumed by the tilapia. This is a very sustainable system and can even be considered natural.
In Walt Disney World in Florida tilapia are grown beneath leafy greens such as lettuce. This nutrient recycling reduces the need for fertilizer for the plants and filters the water for the fish.
There are many examples of integrated aquaculture out there, and more and more are being developed every day. IPM in other areas of agriculture has been being studied for some time now. It seems the use of IPM in fish farming is a relatively new idea. I believe we have a lot more IPM advances to look forward to in the field of aquaculture.
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