In the present study, some reproductive parameters including sex ratios, sexual maturity, gonadosomatic and gonad indices and fecundity of S. schall from the Nile, Egypt were estimated in relation to standard length, weight, age and months. Different patterns of variations were recorded in these parameters. The females and males of S. schall reached maturation at 28.2 and 29.4 cm, respectively. Gonadosomatic index recorded the higher value during the period from January to July for the females of S. schall. The highest value was recorded in March for the males of S. schall. Gonad index recorded higher values during all months. The number of eggs increased with increase in length. Fecundity exhibited variability with age, length and months in the same locality. Fecundity also showed variations with time and locality when compared with other studies. The largest number of S. schall in the current locality was 102600 which recorded in length of 36 cm during May for S. schall. The egg diameter increased from January to August. The largest diameter (1.44 cm) was recorded during June. The highest value was recorded during March for the females and during May and October for the males of S. schall. In conclusion, S. schall is a fecund fish with variations in time and localities. Also, variability of reproductive parameters with age, size, weight and gonad weight are evident.
Imam A.A. Mekkawy and Arafa A. Hassan, 2011. Some Reproductive Parameters of Synodontis Schall (Bloch and Schneider, 1801) from the River Nile, Egypt. Journal of Fisheries and Aquatic Science, 6: 456-471.