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Dec 21 2015

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Building fish enclosure in Lake Nasser, Egypt – Video

Video credit: Ahmed Haggagi Abdullah (Egypt)

Review: Abdel Rahman El Gamal (Founder of the video channel and website)

Source: www.fishconsult.org

Building fish enclosure in Lake nasser

 

 

 

 

 

This video shows the construction of an enclosure in Wadi Abyad in Lake Nasser. This activity was funded by the Challenge Program on Food and Water.

The area of the enclosure varies according to the water level reaching 99 ha, 156 ha and 199 ha when the water level is 170 m, 175 m and 180 m above sea level. The mouth of the enclosure measures about  100 m while water depth within the enclosure fluctuates and ranges from 1-12 m.

The enclosure shown in the video was selected using contour maps having in consideration key criteria such as width at the opening, depth of the opening where the nets will be set, area of the enclosure at different water levels, distance from landing harbors and availability of natural food.

The nets were designed to close up the enclosure mouth completely down to the bottom, to ensure that no fish escape.

Nets are made of multifilament nylon, treated with antifouling, and had a stretched-mesh opening of 3 centimeters. Nets pieces were sewn together using nylon thread to make one piece of 140-m length with ropes at both extremities, the upper part to fix the float line and the bottom extremity to fix the weight line.

The buoys, measuring 100 x 60 x 40cm, were made of painted 2-millimetre (mm) iron sheet, fitted with rings and set at 5-metre intervals along the float line. The float line was made of 12 -mm steel cable with rope. The weight line was made of 8-mm iron chain twisted along a rope to settle the net to the bottom.

After the net closing of the enclosure, the removal of predators was done using bottom gill nets for Nile perch, Lates niloticus,  Malapterurus electricus & Mormyrus kannume and floating gill nets for Hydrocynus froskalii and Alestes dentex.

Afterwards, a total of 2.2 million of Nile tilapia fingerlings of about 15 g and fry of an average weight of 2-5 g were released in the enclosure over three consecutive stockings. Fishing in the enclosure began six months after stocking.

The final report of this project could be visited at the following link:

https://cgspace.cgiar.org/bitstream/handle/10568/3923/PN34_WorldFish_Project%20Report_Jun09_final.pdf?sequence=1

Permanent link to this article: http://fishconsult.org/?p=13037