Journal of Fisheries and Aquatic Science1816-49271996-0751Academic Journals Inc.10.3923/jfas.2012.104.133Synodontis schall (Bloch and Schneider, 1801) (Pisces: Siluriformes: Mochokidae) in The River Nile at Gizza Sector, Egypt: Biological Aspects and Population Dynamics]]>El-KasheifMidhat A. AuthmanMohammad M.N. IbrahimSeham A. 2201272Age, growth, mortality, exploitation, yield and biomass have been investigated for Synodontis schall populations to provide quantitative information about one of the important fishes, inhabiting River Nile, Egypt, in order to improve their fishery management. The length-weight relationships and coefficients of condition were computed. The annual rings on fish vertebrae were used for age determination. The longevity of this species was found to be 6 years. The maximum increase in length was noted during the first year of life and showing a gradual decrease in growth as the fish got older. The von Bertalanffy growth equation was computed. The population parameters were estimated. The instantaneous annual rates of total, natural and fishing mortality were calculated as 0.59, 0.35 and 0.25, respectively. The rate of Exploitation (E) amounted to 41%. Peak values of gonadosomatic index (GSI) for males and females occurred from May to August, indicating one season of spawning. The body length at first sexual maturity (Lm50) and mean selection length (Lc) were equal to 31 and 28 cm, respectively. There is a selective mortality towards smaller fish sizes. Therefore, for management purposes it is recommended to increase the length at first capture to maintain a sufficient spawning biomass for recruitment. Various parameters of fishes of present study when compared with those from other localities showed significant differences. These differences were discussed and found to be attributed to the different ecological conditions in the studied regions.]]>Abass, F.F.,1982Synodontidae.]]>1982Alliot, E., A. Pastoureaud and H. Thebault,1983Dicentrarchus labrax].]]>31181194, (In French)Araoye, P.A.,2001Synodontis schall (Pisces: Mochokidae) in Asa Lake, Ilorin.]]>16105110Authman, M.M.N.,1990Bagrus bayad (Family: Bagridae) from Bahr Shebeen Canal.]]>1990Authman, M.M.N., M.A. El-Kasheif and K.A.S. Shalloof,2009Tilapia species in Damietta Branch of the River Nile, Egypt.]]>1167184Bagenal, T.B. and F.W. Tesch,19781978pp: 101-136pp: 101-136Balon, E.K.,1970Hydrocynus vittatus (Castelnau, 1861) in Lake Kariba, Sinazongwe area.]]>589118Beverton, R.J.H. and S.J. Holt,19561406783Beverton, R.J.H. and S.J. Holt,19571957Beverton, R.J.H. and S.J. Holt,19661966Bishai, H.M. and Y.B. Abu Gideiri,1965Synodontis at Khartoum. I. Age and growth.]]>268597Bishai, H.M. and Y.B. Abu Gideiri,1965Synodontis at Khartoum. II. Food and feeding habits.]]>2698113Bishai, H.M. and Y.B. Abu Gideiri,1968Synodontis at Khartoum. III. Reproduction.]]>31193202Bishai, H.M. and M.T. Khalil,19971997Bloch, M.E. and J.G. Schneider,18011801Boulenger, G.A.,1907Diomande, D., L. Doumbia and G. Gourene,2009Synodontis Bastiani Daget, 1948 and S. Schall (Bloch and Schneider, 1801).]]>276676El-Kasheif, M.A., M.M.N. Authman and S.A. Ibrahim,2007Cyprinidae fish, Labeo niloticus, from the River Nile at El-Kanater El-Khyria, Egypt.]]>2721Fulton, T.W.,190220122GAFRD.,20092009Gayanilo, F.C., P. Sparre and D. Pauly,2005Vol. 8,Pages: 168Pages: 168Ghorab, H.M., A.R. Bayoumi, M.L. Bebars and A.A. Hassan,1986Epinephelus chlorostigma (Pisces, Serranidae) from the red sea.]]>121333Gulland, J.A.,19694154154Gulland, J.A.,1971Vol. 97,Pages: 255Pages: 255Gulland, J.A.,1983Vol. 1,pp: 223pp: 223Halim, A.I.A. and S.A. Guma'a,1989Synodontis schall (Bloch-Schneider, 1801) from the White Nile near Khartoum.]]>178243251Hassan, A.A.,2007Synodontis schall and Mormyrus kannume from the Nile at Assiut, Egypt.]]>2007Copley, H.,1958Pages: 172Pages: 172Ibrahim, S.A., S.A. Gaber and M.A. El-Kasheif,2005Synodontis schall in the River Nil at El-Ayat, Giza, Egypt.]]>9249270Idodo-Umeh, G.,2005147193Khallaf, E.A.,1977Schilbeidae from lake Nasser.]]>1977Khallaf, E.A.,1988Bagrus docmac in Lake Nasser.]]>2547552Khallaf, E.A. and M. Authman,1991Bagrus bayad (Forskal) in Bahr Shebeen Canal.]]>487109Khallaf, E.A. and M. Authman,1991Bagrus bayad, Forskal, in Bahr Shebeen Canal.]]>4123138Khallaf, E.A. and M.N. Authman,2010Mormyrus kannume, Forsskal, 1775), from Bahr Shebeen Nilotic Canal, Egypt.]]>2357375Kheir, M.T.,1993Synodontis schall.]]>1993Laleye, P., A. Chikou, P. Gnohossou, P. Vandewalle, J.C. Philippart and G. Teugels,2006Synodontis schall and Synodontis nigrita (Ostariophysi: Mochokidae) from the Oueme River, Benin.]]>136193201Latif, A.F.A.,19741974Latif, A.F.A., S.A. Salem and F.F. Abbas,198912321327Le Cren, E.D.,1951Perca fluviatilis).]]>20201219Lee, R.,19204132Luff, R.M. and G.N. Bailey,2000Synodontis schall (schall) from Tell El-Amarana, Middle Egypt.]]>27821835Mahmoud, U.M. and I.A.A. Mekkawy,1991Synodontis species from the Nile at Egypt.]]>20111Mekkawy, I.A.A. and A.A. Hassan,2011Synodontis Schall (Bloch and Schneider, 1801) from the River Nile, Egypt.]]>6456471Mekkawy, I.A.A. and U.M. Mahmoud,1992Synodontis populations of Egypt.]]>791110Mohamed, E.H.A,2010Synodontis (Siluriformes: Mochokidae) catfish species in the White Nile and Lake Nubia.]]>881723Moreau, J., C. Banbino and D. Pauly,1986Cichlidae) Populations.]]>1986pp: 201-206pp: 201-206Nawar, G.,1959Synodontis schall (Bloch-Schneider, 1801).]]>40139141Nelson, J.S.,20064th Edn.,Pages: 601Pages: 601Ofori-Danson, P.K.,1992Synodontis (Pisces: Mochocidae) in the Kpong Headpond in Ghana.]]>354961Nnaji, J.C., A. Uzairu, G.F.S. Harrison and M.L. Balarabe,2007Oreochromis niloticus and Synodontis schall of River Galma, Zaria, Nigeria.]]>624202426Osman, A.M.,2005Lithognathus mormyrus (Teleostei, Sparidae) in Mediterranean waters off Alexandria, Egypt.]]>31274280Patterson, K.R.,1992Sardinops sagax (Jenyns).]]>40821831Pauly, D.,198039175192Pauly, D.,1983234152Pauly, D.,198421719Pauly, D. and J.L. Munro,198422121Pauly, D. and M.L. Soriano,19861986pp: 491-496pp: 491-496Ricker, W.E.,196926479541Ricker, W.E.,19751911382Rizkalla, W. and E.G. Yoakim,1977Synodontis schall (Bloch-Schneider). III. Pre-ovulatory and post-ovulatory corpora lutea.]]>5239244Rizkalla, W. and E.G. Yoakim,1981Synodontis schall.]]>23243255Salem, S.A. and F.F. Abbas,1990Synodontids (Auchenoglanis biscutatus, Synodontis serratus and S. schall) from Lake Nasser: Part II-Major biochemical components of the gonads.]]>11163170Sparre, P. and S.C. Venema,19921992Sparre, P. and S.C. Venema,19891989Tharwat, A.A.,1998Synodontis schall (Bloch-Schneider) of the River Nile, Egypt.]]>2113Van Rensburg, K.J.,1966Tilapia mossambica (Peters) in De Hoop Vlei and Zeekoe Vlei.]]>917Von Bertalanffy, L.,193810181213Wassef, E. and H. El-Emary,1989Dicentrarchus labrax L. in the Egyptian Mediterranean waters off Alexandria.]]>13327345Weatherley, A.H. and H.S. Gill,1987Pages: 443Pages: 443West, G.,199041199222Wootton, R.J.,19901st Edn.,Pages: 404Pages: 404Wootton, R.J.,19944th Edn.,Pages: 404Pages: 404Bruton, M.N.,199028716