WWW.WAS.ORG • WORLD AQUACULTURE • MARCH 2018 67 that will be 5 km long, 24 m wide, and 3.5 m deep. Cultivating plants such as common reed Phragmites australis, cattail Typha domingesis, and rushes Juncus sp. will be used to achieve biological treatment of water. In addition, we are currently developing a molecular identification technique for the parasite, including detection of its virulence genes, that can be used as a tool to limit its spread to fish farms or other lakes in Egypt. Notes Nevien Abdelkhalek, Mohamed El-Adl, Mohamed Salama, Moustafa Al-Araby and Ahmed Hafez, Department of Internal Medicine, Infectious and Fish Diseases, Faculty of Veterinary Medicine, Mansoura University, Egypt Email: neven_km@mans.edu.eg, nevienabdelkhalek@gmail.com References El-Sayed, S.A., E.M.M. Moussa, and M.E.I. El-Sabagh. 2015. Evaluation of heavy metal content in Qaroun Lake, El-Fayoum, Egypt. Part I: bottom sediments. Journal of Radiation Research and Applied Sciences 8(3):276-285. GAFRD (General Authority for Fish Resources Development). 2017. Annual report of the General Authority for Fish Resources Development for fisheries statistics in Egypt. the lake. Currently, fishing in the lake is totally prohibited by the government and the lake is almost free of fish that contribute to national production. How to Solve Such a Disaster? This has been carried out through two main approaches. One approach is a project, supervised by GAFRD, to dredge the bottom of Lake Qarun to remove accumulated organic matter and improve water quality in the area near the entrance of the Al-Bats drain. A Gaferd4080 dredge (Fig. 3) and a Watermaster multipurpose dredge (Fig. 4) were used for this purpose. Water and sediment with high organic matter content were pumped from the lake bottom to sedimentation basins. After settling, water was returned to the lake. The other approach is to interfere with the life cycle of the parasite by stopping the program to stock the lake with fry or broodstock, thereby reducing the number of fish hosts for the parasite. Dredging the lake bottom also removes free-living stages of the parasite. Future activities proposed to address the problem include digging channels to overcome receding water levels in the lake, disinfection of the end of Dayer El-baraka pond, and increasing water flow to the lake to reduce the high salinity. Plans are being developed to design sedimentation ponds and a channel in front of the main El-Bats drain. This will include a weir and a channel TABLE 1. The annual catch (t) of different fish species in Lake Qarun, Egypt, from 2006 to 2015 (GAFRD 2017). YEAR 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 FISH Tilapia 762 1350 1454 1071 996 1173 1226 1265 1312 426 Shrimp - 151 126 661 684 699 912 902 862 102 Eels - - - 10 8 11 6 8 6 76 Sea bream - - - - 5 7 2 2 5 - Siganids - - - - 1 5 3 4 2 - Grey mullet 480 585 600 1021 1379 1424 1283 1207 1198 191 Sea bass - 25 16 22 24 19 15 12 10 17 Sole 390 845 935 581 783 1018 946 1002 1111 176 Others 16 116 53 34 23 8 17 18 12 136 Total 1648 3072 3184 3400 3903 4364 4410 4420 4518 1124 FIGURE 3. Gaferd4080 dredger to clean Lake Qarun. Photo: Ahmed Hafez. FIGURE 4. The Watermaster multipurpose dredge working to clean Lake Qarun. Photo: Ahmed Hafez.
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