There is no information about the natural diets and competition of Iraqi native shrimp Metapenaeus affinis and the invasive shrimp Macrobrachium nipponense, However, the aim of this study is to identify the diet items of M. affinis and M. nipponense based on the analysis of stomach contents in order to identify the existence of a dietary overlap the two species. A total of 630 Stomachs of M. affinis and 780 stomachs of M. nipponense were investigated. The result that the diets composition of M. affinis consisted mainly of eleven items belonging to twenty one types of food. While in the stomach contents of M. nipponense were categorized into thirteen types belonging to thirty items. These main groups were Phytoplankton, aquatic plant, Zooplankton, Crustacean, Fish larvae, Mollusca, sediments, Insects, unidentified matter, unidentified Invertebrate, unidentified Algae, Amphipods and Annelid. The diets of M. affinis, were consisting of aquatic plant (25 %), followed by Phytoplankton (16%) and fish larvae consisting the lowest percentage (1.5 %). The Phytoplankton was dominating the stomachs of M. nipponense (21 %) then comes the insects 12%, and fish the larvae consist of the lowest percentage (2 %). High feeding intensity of M. affinis was observed during March, April and May, whereas low feeding intensity was observed during July, August, September, October, November and December (maximum during April 41% and minimum in December (3%). While the high feeding intensity of M. nipponense was achieved during May, June and July whereas, the low intensity was observed during September, October, November and December (maximum in June 40 % and minimum during October 10%).

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