Geographical distribution of the daphnia crustacean in the artificial Hajarah lake in Sebha, Libya.

Abstract

This study was conducted in the Hajarahartificial lake of treated sewage water in Sabha city, south of Libya during the period (3 / 2012-8 / 2012), during which samples of water and Plankton (Daphnia) were collected once a month. Some physio-chemical properties of lake water were measured.Daphnia numbers also examined and calculated. The study found that the lake water contains dissolved oxygen at a concentration between (5.74 - 12.53 mg / L), temperature (18.15 - 32.3 m) and pH (6.76 - 8.24). The results showed that the lake water has low salinity (0.774) - 1.011 g / l).It was found that the distribution and spread of Daphnia in the lake was concentrated in the edges  andin its center and less prevalent in the north of the lake, where the highest percentage of Daphnia was recorded in the south direction (25%) and the lowest in the north direction (9%). Which represent the water entrance to the collective reservoir to the lake. This depending on the currents movement in the lake, which works to transport the raiders with them.The results of the study showed that the water of the lake was suitable for the growth and reproduction and life of the species, as the temperature, pH and salinity were within the appropriate limits for growth and reproduction.