Structure of Fish Assemblage in Relation to Some Ecological factors in Himreen Dam Lake, Iraq

Spatial and temporal variability of fish assemblage in Himreen Lake wasstudied from summer 2014 to spring 2015. Water temperature, electrical conductivity,dissolved oxygen, transparency and potential hydrogen ion were measured from threesites in the Lake. Several fishing methods were adopted to collect fish including; gillnets, cast net, hook and line and hand net. The results showed that the fish assemblageconsisted of 19 species representing seven families. Number of species increased insummer and spring and sharply decreased in winter. Luciobarbus grypus was the mostabundant species comprising 23.6% of the catch, followed by Carassius auratus(20.07%) and Cyprinus carpio (11.39%). The dominance (D3) value for the main threeabundant species was 55.06%. The overall values of diversity index ranged from 1.71 inwinter to 2.43 in summer, richness index from 2.4 in winter to 2.94 in summer andevenness index from 0.71 in winter to 0.84 in autumn. Associations between thedistribution of fish species and the environmental variables were quantified by usingcanonical correspondence analysis (CCA).