Food Habits of Jeri (Silurus triostegus Heckel, 1843) in the Southern Sector of the Euphrates River, Southern Iraq

Abstract

Food habit of jeri (Silurus triostegus) was studied in the southern sector of the Euphrates River. Samples were collected on a monthly basis for the period from December 2013 to November 2014.The study examined the feeding intensity and feeding activity and analyses of food components through applying three methods of analysis. Relative index of importance of the consumed food categories was calculated. Results showed that the highest value for food intensity was in June (2.8) and the lowest (1.7) in December. The highest values of food activity were encountered in the warmer months of the year achieving its peak in May (93.7). Results also indicate that individual of this species feed mainly on fish as this category formed the highest contribution adopting the three analytical methods, namely numerical, volumetric and frequency of occurrence. This food component, however, formed the bulk contribution of the relative importance (97.08- 100%) in the diet. This, absolutely, mark this species as piscivore. Shrimp came second in importance (0- 2.9%) in spite of its meager contribution in the food components. The study also revealed the phenomenon of self- predation (cannibalism) exhibited by some members of the investigated population.