Iraq's fisheries played an important role in its economy in the 1960s and 1970s; after the sudden U.S. invasion of Iraq in 2003, the resulting chaos with governmental laws and regulations, there was a significant weakening of the economy as a whole, including aquaculture [12; 14; 15]. In recent years, the volume of fish production in Iraq has gradually increased, with aquaculture accounting for about 1% of the country's GDP [14-16]. The problem of increasing the volume of aquaculture production remains urgent in modern conditions, so the use of the fish crop rotation method in agriculture of the country will successfully solve the issues of increasing fish productivity of the most common cultivated species - carp. Obtaining marketable fish products in conditions of aqua-crop rotation method allows the most efficient use of pond areas.
Crop rotation is the practice of growing a series of different crops in the same area in consecutive seasons, which provides the soil with different nutrients. Application of crop rotation method in fish farming provides an opportunity to increase fish productivity and crop yield in the ponds [1; 2; 5; 7]. In the Middle Eastern countries, the aqua-crop rotation method has been developed in recent years; in particular, rice planting and fish farming are carried out alternately on the same pond areas, which allows eliminating the contradictions between these crops and increasing the production efficiency [11; 22]. In Iraq, rice cultivation began in ancient times from 400 B.C., and then rice cultivation spread to Syria, Turkey, and Iran [9; 10].
In the early 2000s, for a variety of reasons, rice cultivation in the country shrank to 88,000 ha in 2008. However, already in subsequent years, there was an increase, and in 2013 381 thousand tons of rice were produced, in 2014 - 436 thousand tons [14; 16; 18], with an average yield of about 3.3 t/ha. To increase rice yield, a method of aqua-crop rotation is being developed where pond fish residues contribute to decomposition and assimilation of organic matter, loosen and sour the soil and enrich it with nitrogen, which allows for a good yield [4]. Such a production technology combined with fish farming is effective and environmentally beneficial in terms of using the bioproductive potential of water bodies and the surrounding land.