Egg Quality and Fecundity of Clarias gariepinus Broodstock Cultured at Different Water Depths in Indoor Concrete Tanks
Otoh, A. J. *
Department of Fisheries and Aquaculture, Faculty of Agriculture, Akwa Ibom State University, Obio Akpa Campus, Oruk Anam, Nigeria.
Udoh J. P.
Department of Fisheries and Aquatic Environmental Management, University of Uyo, Akwa Ibom State, Nigeria.
Okoko A. C.
Ministry of Agriculture, Directorate of Fisheries, Akwa Ibom State Civil Service, Idongesit Nkanga Secretariat Complex, Uyo, Akwa Ibom State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: To investigate the fecundity and egg quality of C. gariepinus broodstock raised at 0.50 m, 0.75 m and 1.0 m pond water depth.
Study Design: Treatments were assigned using complete randomized design.
Place and Duration of Study: Fish Farm Complex of the Akwa Ibom State University (AKSU), Nigeria.
Methodology: Nine female broodstock of C. gariepinus averaging 2.51 – 2.53 kg and 64.30 – 67.24 cm were raised for six months at 0.50 m, 0.75 m and 1.0 m pond water depth; referred to as treatments A, B and C, respectively Experimental fish were fed 42% crude protein commercial feed. The fecundity, relative fecundity, gonadosomatic index (GSI), egg weight and size were assessed.
Results: The results revealed that the egg quality significantly (P=.00) increased with the water depth of the broodstock culture tank. Egg weight and GSI values from treatment C (363.40±0.57 g and 14.40±0.01 %, respectively) were significantly (P = .007) higher than those of treatment A (267.30±0.06 g and 10.66± 0.06 %, respectively) but showed no significant difference with those of Treatment B (331.07±1.20; 13.09±0.04 %). The corresponding egg diameter (1.01±00; 1.08±0.03 and 1.21± 0.01g), fecundity and relative fecundity of broodstock also increased with pond water depth (P = .003): 182,120.0±503.67, 72.66±0.40 > 185,618.3± 745.98, 73.37±0.18 > 188, 967.1± 295.19, 74.89±0.18, respectively.
Conclusion: The water depth of the broodstock maintenance pond enhances fecundity and egg quality; it is better at 1.0 m depth for successful fry production. Broodstock may be maintained at lower pond water depths for growth purposes; prior to breeding.
Keywords: Artificial fertilization, breeding, fish stress, hatchery production