Integrated multi-trophic aquaculture (IMTA)
Integrated multi-trophic aquaculture (IMTA) is a method that uses by-products of one species to be recycled by the uptake through another species. Fed aquaculture organisms, such as fish or shrimp, are held along with other extractive species, such as filtering mussels, oysters, sea cucumbers or macroalgae. The extractive species of a lower trophic level take up the waste products of the fed species of a higher trophic level, thus preventing an additional input of nutrients into the surrounding ecosystem. The different organisms must not be grown directly in the same place, but they need a nutrient and energy exchange through the water.
IMTA systems can be operated in tanks or ponds on land or in the open sea, in freshwater and in the marine realm. Ideally, such an IMTA system should be balanced so that all nutrients released by the higher trophic levels are taken up by species of lower trophic levels. Here, special attention must be paid to the selection of candidates and the scale of the operation. The extractive species not only serve as a biofilter, but should also constitute an additional product with market value. This leads to synergistic benefits, because an IMTA system in balance not only provides a high environmental sustainability by the extractive species as biofilter, but also greater economic stability and minimum risk through the diversification of products.