NATURAL FEEDING OF SOME FISHES FROM THE POLLUTED SOUTH PART OF DIYALA RIVER

Abstract

A total of 105 specimens of Bunni Barbus sharpeyi (Gunther, 1874), 95 fish of Khishni Liza abu (Heckel,1843) and 74 of Common carp Cyprinus carpio L.) were collected from the south part of Diyala River, a polluted section. The results showed that the diet of Bunni didn’t differ from that of non-polluted water. Aquatic plants and their seeds ranked first (31.4, 39.7%), detritus second (30.4%, 32.0%) and algae third according to volumetric (V%) method and ranking index (R%) respectively. Aquatic plants was the most occurred (O%) diet (28.1%) followed by detritus in fish stomach. This made Bunni to be herbivorous fish (84.2%). Khishni was found in fish feed mainly on detritus (17.7, 25.0%), aquatic plant (17.9, 19.7%) and zooplankton. Detritus was also, the most occurred diet (22.1%). Khishni was an omnivorous fish with 51.3% plant origin. However, Common carp, was feeding mainly on aquatic plants (22.1, 35.2%), detritus (17.5, 20.8%) and algae. They ranked in the first three places of fish diets according to volumetric method and ranking index respectively. Whereas, aquatic plants were the most occurred diet (26.5%) in the stomachs. Neither mollusca nor insects and its larvae took an important role in the diet of carp. Carp was also an omnivorous fish with plant in origin and formed 57.1% of diet volume. This proved the effect of plant materials exceeding in the river, on fishes diet. The relationship between the total length and total weight of studied fish (Bunni, Khishni and Common carp) were represented by the following equation respectively:log W= -2.12 + 2.04 log L (r = 0.886, n = 105, P<0.001) log W= -3.11+ 2.66 log L (r = 0.873, n = 95, P<0.001) log W= -1.30 + 2.74 log L (r = 0.762, n = 74, P<0.001)