| |
ISS013-E-76441 (4 Sept. 2006) --- Aquaculture in the Nile delta, Egypt is featured in this image photographed by an Expedition 13 crewmember on the International Space Station. In the last three decades, a series of lagoons and lakes with greater and lesser connection to the sea have been greatly modified for the production of fish along the northeast coast of the Nile delta. Partial sunglint in this image reveals numerous details in one such fishery. Waves generated by northwesterly winds (lower left to upper right) have generated the frond-like sand spit along the coast (top). Faint sea swells are visible at upper left. Dark patches in the center are shadows cast by small clouds (also visible as dull white masses against the silver-grey sunglint). Dark curved lines on the inshore (western) side of the spit show prior positions of the spit. Most of Musallas Lagoon occupies the lower half of the image. By contrast with spit, the shores of the lagoon are everywhere occupied by a network of man-made structures--mainly short dikes enclosing hundreds of aquaculture ponds. The total area under fish production is estimated to be 8,000 hectares in the lagoon, which provides more than half of the aquaculture production for Egypt, largely in the form of two species of mullet. An outlet to the Mediterranean Sea (top right), allows sea-water recharge to the lagoon. Wind helps to circulate the water in this shallow lagoon--bright wind streaks on the lagoon (lower left) show this circulation driven by the north-northwest wind on this day.
Aquaculture in the Nile Delta:
In the last three decades, Egypt has greatly modified a series of lagoons and lakes along the northeast coast of the Nile Delta for the production of fish. Partial sunglintin this astronaut photograph reveals numerous details in one such fishery. Sunglint is light reflected directly back from a surface--usually water--to the viewer (or a camera or satellite sensor). Waves generated by northwesterly winds (lower left to upper right in this view) have created the frond-like sand spit along the coast (image top). Faint sea swells are visible at image upper left as a pattern of dark and light lines. Dark patches in the center of the image are shadows cast by small clouds, which appear pewter-gray compared to the golden sunglint on the watery surfaces below.
Dark, curved lines on the inland (western) side of the spit show old positions of the spit. Most of Musallas Lagoon occupies the lower half of the image. By contrast with the spit, the shores of the lagoon are occupied almost entirely by a network of artificial structures--mainly short dikes enclosing hundreds of aquaculture ponds. The total area devoted to fish production in the lagoon is estimated to be 8,000 hectares (19,768 acres), which constitutes more than half of Egypt's aquaculture production. An outlet to the Mediterranean Sea (top right) allows seawater recharge to the lagoon. Wind helps to circulate the water in this shallow lagoon; bright streaks on the lagoon (lower left) show the north-northwest direction of the wind on this day.
The intense aquaculture in the Nile Delta was born out of the impacts of the Aswan High Dam. The construction of the Aswan High Dam nearly a thousand kilometers upstream stopped the dramatic, and often catastrophic, seasonal floods that previously delivered nutrient-rich sediment from the Nile to the Mediterranean Sea. Nutrient concentration dropped to such a degree that the sea fishery around the delta collapsed in the mid-1960s to about 3 percent of the catch in preceding years. Aquaculture in various parts of Egypt during the last 30 years has partly made up for this loss, and consumption of fish has doubled in Egypt, although exports have not recovered. | |
