Study of some biological aspects of the Nile Carp, Labeo niloticus (Pisces, Cyprinidae) from Khashm El-Girba Reservoir and Atbara River; Eastern Sudan: II, length-weight relationship, condition factor and age structure

This study was undertaken to assess the length-weight relationship, condition factor and age structure, of the Nile carp, Labeo niloticus, in Khashm El-Girba reservoir and Atbara River, Sudan, from December 2015 to November 2016. Samples of fish were collected bi-monthly from three locations, namely; Um Aswad (Atbara River), El-Remila and El-Monaba (Khashm El-Girba reservoir), using beach seine nets of 1.2, 4.0 and 7.0 cm stretched mesh. Out of a total number of 1,190 specimens of L. niloticus collected from the three sampling sites, 189 specimens were randomly selected to determine age. The relationship between length and weight indicated negative allometric growth pattern in all three locations, where the slope (b) of the (LWR) was highly significant (p<0.001) and ranged from 2.178 to 2.885. The mean condition factor (K) varied monthly in the three locations with values ranging from 1.671 in Um Aswad (Atbara River) to 2.548 in El-Monaba (reservoir). Although the age of L. niloticus ranged from 0+ and 3+ years, yet, most of the studied fish are between age 0 + and 1+.

Comparative study on African catfish (Burchell, 1822) hypophysation using ovaprim and chicken pituitary gland extract

Comparative study on African catfish hypophysation indices using ovaprim and chicken pituitary gland extract (CPGE) was carried out. Sixteen (16) African catfish brood stocks between 1100 and 2300 g in ratio 2:1 and four (4) numbers of layer birds (Gallus gallus domesticus) between 1200 and 2200 g in ratio 1:3 were used respectively. The experiment was batched into “A” and “B”. Batch ‘A’ was placed on ovaprim while batch ‘B’ was placed on CPGE. An indoor hatchery vat, measuring 0.6096 m x 1.8288 m x 0.3048 m each was used for the incubation. Digital measuring kits were used to monitor water quality parameters and measurement of the brood stocks weights independently. Brood stocks on ovaprim and CPGE treatments had the following mean hypophysation indices in these order: fecundity (11100±7690 and 17760±13863), latency period (9.53±0.54 and 9.77±0.49), fertilization percentage (94.03±5.90% and 90.6±10.11%), hatchability percentage (75.6±0.81% and79.35±10.27%), number of eggs produced (5889±657.37 and 9403.33±589.80), total number of larvae hatched (4717.33±1111.0 and 7111.33±506.64), SGR (0.67±0.31 and 1.1±0.31), and survival rate (64.81±0.71 and66.24±2.19) respectively. There was no significant difference (p = 0.05) in the mean values of fecundity, latency period, fertilization and hatchability percentages in both treatments but there was significant difference (p ≤ 0.05) in number of eggs produced and total number of larvae hatched in both treatments. The water quality parameters were within the range for induced breeding techniques and there was no significant difference (p= 0.05) in both experiments. Both ovaprim and CPGE had excellent results from the induced breeding of Clarias gariepinus and yielded good results. Therefore, CPGE could be recommended from the view point of excellent results and its availability from chicken slaughter houses as against ovaprim which are imported.