How has the Aswan High Dam affected fish populations in the Nile River and Mediterranean Sea?

The construction of the Aswan High Dam has significantly altered fish populations in both the Nile River and the Mediterranean Sea due to changes in water flow, migration patterns, and nutrient distribution.12

Impact on the Nile River

The dam acts as a physical barrier that prevents many migratory fish species from moving upstream to Lake Nasser, leading to a reduction or disappearance of fish populations that previously thrived in the Nile during flood seasons. Conversely, the creation of Lake Nasser has established a new environment where species such as the Nile perch and other fish thrive, supporting a developed commercial fishing industry.23

Impact on the Mediterranean Sea

The dam has caused a dramatic reduction in fish populations offshore of the Nile Delta. This decline is primarily attributed to the dam’s impoundment of nutrient-laden silt, which previously flowed into the Mediterranean Sea. The resulting decrease in these waterborne nutrients has led to a significant drop in the number of species, such as anchovies, in the eastern Mediterranean.12