Impact of recent rehabilitation Projects on Lake Burullus aquatic ecosystem

For this study, Lake Burullus, the second-largest lake on Egypt’s northern Mediterranean coast, was selected. Prior to and during the rehabilitation process, changes in lake area, water surface area, plant cover, phytoplankton, zooplankton, and fish productivity have been discussed. Intense human activities and climate change are altering the lake’s water bodies. Although the area of the lake’s water area declined by 44.97% (14,503.68 ha), the area of vegetation cover increased by around the same percentage, the area of agriculture increased by 45.52% (10529.02 ha), and the area of the sand bar and urban areas decreased by approximately the same proportion. All of the lake’s biological characteristics were also affected by raw sewage discharges.The water quality of Lake Burullus began to improve after the Egyptian government developed the lake’s northern and eastern parts, increasing the inflow of saltwater. Many aquatic plants, including Najas armata, Myriophyllum spicatum, Ceratophyllum demersum, and Azolla filiculoides, have disappeared from the eastern sector of the Lake due to rising water depth and salinity. The total number of phytoplankton species dropped from 195 to 111, accompanied by an increase in abundance and diversity of marine species that reflects this improvement. In comparison to the central and eastern basins, the western basin had the highest zooplankton density. The overall annual capture from Lake Burullus increased from 49,704 MT (Metric Ton) in 2013 to 104,523 MT in 2022, with a significant increase in the production of marine fish species such as sea breams, sea bass, and mullets. This suggests that the lake’s water quality and the aquatic communities it supports are primarily influenced by the water exchange with the sea and the lake’s circulation patterns, which should be considered in future rehabilitation initiatives.