Al-Doori, M.L. and Al-Doori, N.L. 2017. Effect of Photoperiod on Growth and Reproduction of Cyclops varicans G. O. Sars, 1863 (Cyclopioda – Copepoda ). Ibn AL-Haitham Journal For Pure and Applied Sciences. 27, 2 (Apr. 2017), 51–59.