ABSTRACT. – The co-occurrence of two anostracan species Branchinectella media and Phallocryptus spinosus have been surveyed monthly in four saline lakes from the Aures region (Chott Tinsilt, Garaa El-Tarf, Sebkha Djendli and Garaa O’Lembarek), in North-East Algeria, between 2013 and 2014. Branchinectella media occurred during the winter at low water temperatures ranging between 5 and 16 °C and a salinity between 2.24 and 44 ppt (g/L), while P. spinosus preferred spring with a temperature range between 18 and 22 °C and a salinity from 12.08 to 48.6 ppt. The presence of both species overlapped only in March in the four sites. Phallocryptus spinosus always occurred with higher monthly densities between 5.2 ± 0.99 and 27.7 ± 3.81 ind.L–1 versus 1.65 ± 0.64 to 10.55 ± 0.78 ind.L–1 for B. media. Phallocryptus spinosus was two times larger than B. media (F = 26.80, P < 0.001) and its females were two times more fertile (t = 12.89, P < 0.0001) in the four sites. From the present study, we concluded that B. media, which is considered as a rare species according to the literature, was sensitive to environmental factors, mainly the temperature, and was dominated by P. spinosus, making it vulnerable, especially to the effects of the predicted climate warming.