Sources: E.B. Worthington, Middle East Science, 1946. Publisher: London: His Majesty’s Stationery Office
Caption of the photo: Fish-pass on the Jebel Aulia dam in Sudan. Above the dam a shallow lake extends to 340,000 acres for six months in each year. It offers a big opportunity for fishery development.
The following paragraph is cited from the above source: Many of the Nile fish undergo pronounced migrations up and down the river, probably for purpose of breeding, so that the provision of adequate fish-passes at the dams is important. No fish-pass was installed at the Sennar dam, although temporary one was erected shortly after its construction and subsequently fell into disrepair and was demolished. It is significant here that one particular fish, the large-sized Nile perch, (Lates niloticus), accumulated in great abundance below the dam for some years after its construction, but now, some thirteen years later, is rarely caught there. This suggests that the passage of this fish up and down the Blue Nile is a necessary part of its life-history, and that the installation of a proper fish pass at the dam should be considered. A pass was installed at the new Jebel Aulia dam, and it is said to be used extensively by many kinds of fish. It is not an ideal pass, however, and might have been considerably more effective if built in such a way that the water emerged from the foot of the pass close to the main rush from the sluice gates.