Structural diversity of fish assemblage in the southern sector of main outfall drains northwest of Basrah, Iraq

الملخص EN

Fish assemblage was studied for a first time in the Southern part of Main Outfall Drain, in the Al-Kaii bridge region, northwest Basrah Iraq in the Al-Kaii bridge region.

The study was conducted during the period from May 2016 to April 2017.

Many types of fishing nets were used to collect the samples.

Water temperature ranged from 14º C in February 2017 to 30º C in July and August 2016, while salinity ranged from 9 PSU in April 2017 to 42 PSU in December 2016.

A total of 6161 individuals of fishes were caught represented 21 fish species.

Six species were freshwaters fishes; four were alien species and 15 marine species.

The species Acanthurus sohal was fished for the first time from the Iraqi inland waters.

The most abundant three species were Poecillia latipinna, Planiliza subviridis and Thryssa whiteheadi formed 26.68%, 25.00% and 17.58%, respectively of the total number of samples.

Values of the diversity index varied from 1.23 in November to 2.17 in May, evenness index values fluctuated between 0.52 in June to 0.88 in May, whereas richness index ranged from 1.14 in January 2017 to 2.02 in May.

The present study concluded that there is a significant monthly fluctuation in salinity and the composition of fish community was changing continuously according to the salinity variation.