World Aquaculture March 2019

WWW.WA S.ORG • WORLD AQUACULTURE • MARCH 2019 67 range of most freshwater fish species fell between 6 and 9. The target water quality range for ammonia, nitrite and phosphate concentrations for most fish species were <0.025 mg/L, <0.5 mg/L and 0.1 mg/L, respectively. Although water was renewed twice daily, the feeding intensity may still have contributed to increased excrements and output of metabolic wastes which would have resulted in increased ammonia levels. What may however be deduced from the fry survival is that silver catfish at this early life stage is hardy, a necessary attribute for a fish suitable for aquaculture. On the other hand, a further reduction or elimination of ammonia build-up strategies such as flow through or RAS might have yielded a better growth and should be the focus of further investigations. Conclusion The ready acceptance of extruded feed by silver catfish fry has revealed important information that will serve as a protocol for its successful rearing. The data garnered from the detailed intensive study of the early life stage and water chemistry requirements of silver catfish fry in a controlled indoor set-up presents an alternative catfish for economic empowerment and diversification. Notes H.A. Fashina-Bombata ( bombatta2002@gmail.com ), A.M. Hammed, F.G. Owodeinde, A.A. Jimoh, P.E. Ndimele, A.MTaiwo and Z.Y. Yeni, Department of Fisheries, School of Agriculture, Lagos State University, Epe, Nigeria. E.P. Anwa-Udonduiah, Nigerian Institute for Oceanography and Marine Research, Victoria Island, P.M.B. 12729, Lagos, Nigeria. We thank the Lagos State Research and Development Council for the grant provided for this study. References Abowei, J.F. and A.I. Hart. 2008. Artisanal fisheries characteristics of the fresh water reaches of lower Nun River, Niger Delta, Nigeria. Journal of Applied Science and Environmental Management 12(1):5-7. Department of Water Affairs and Forestry. 1996. South African water quality guidelines, 2 nd edition. Volume 6: Agricultural Water Use: Aquaculture. Ed. S. Holmes. CSIR Environmental. Services, Pretoria. Republic of South Africa. Erondu, E.S. 1997. Aspects of the biology of Chrysichthys nigrodigitatus (Lacépède) in the New Calabar River and its aquaculture potentials. Ph.D thesis, University of Nigeria, Nsukka, Nigeria. FAO (Food and Agriculture Organization).1969. Fisheries survey in the western and mid-western regions of Nigeria. FAO/SF74/NIR6, Food and Agriculture Organization of the United Nations, Rome, Italy. Holden, M. andW. Reed. 1991. West African Freshwater Fishes. Longman Group Ltd., London, England. Pangni, K., B.C. Atsé and N.J. Kouassi. 2008. Effect of stocking density on growth and survival of the African catfish, Chrysichthys nigrodigitatus (Lacépède 1803) larvae in circular tanks. Livestock Research for Rural Development 20(7):129-135. Risch, L. and E.J. Vreven. 2007. Claroteinae. Pages. 607-629 In : M.L.J. Stiassny, G.G. Teugels and C.D. Hopkins, editors. The fresh and brackish water fishes of Lower Guinea, West-Central Africa. Volume I. Collection Faune et Flore tropicales 42. Institut de Recherche pour le Développement, Paris, France, MuséumNational d’Histoire Naturelle, Paris, France, and Musée Royal de l’Afrique Centrale, Tervuren, Belgium. Srivastava, P.P., S. Raizada, R. Dayal, S. Chowdhary, W.S. Lakra, A.K. Yadav, P. Sharma, and J. Gupta. 2012. Breeding and larval rearing of Asian catfish, Clarias batrachus (Linnaeus, 1758) on live and artificial feed. Journal of Aquaculture Research and Development 3:134. doi:10.4172/2155-9546.1000134 TABLE 2. Water quality during the study period. Week Temp Dissolved oxygen pH Ammonia Nitrite Phosphate (C) (mg/L) (mg/L) (mg/L) (mg/L) 0 27.2 13.4 6.60 3.33 0 0.27 2 27.3 12.1 6.17 0.50 0 0.25 4 27.2 12.8 7.01 0.10 0 0.50 6 27.7 13.1 7.75 0.25 0 0.42 8 27.8 14.0 7.29 2.00 0 0.30 10 28.5 15.1 7.53 2.00 0 0.35 12 28.3 14.2 7.73 2.00 0 0.15 Values are the mean of three replicates. FIGURE 7. Growth (weight, left, and length, right) of silver catfish fry over 12 weeks.