SOME ASPECT OF THE BIOLOGY OF Brycinus nurse (Alestidae, Ruppell, 1832) FROM THE LOWER RIVER BENUE RIVER NIGERIA
The feeding habits and reproduction of Brycinus nurse was studied for 12 month period, from September, 2021 to August, 2022. A total number of 241 specimens were obtained from fishermen at the biggest commercial fish landing sites along the bank of River Benue, (Wurukum and Wadata) Makurdi and taken to the laboratory for morphometric measurements, stomach content examination, and fecundity estimation. Out of 241 specimens obtained, 110 (45.61%) were males, while 131 (54.32%) were females with the male to female sex ratio of 1:1.2. The standard length and total weight ranges of males were 7.0-17.0cm with a mean of 10.76±0.218 and 6.26-104.77g with a mean of 30.094±1.969 respectively, Females were 7.0- 17.2cm with a mean of 11.09±0.192 and 6.47-103.48g with the mean of 32.602±1.747 respectively. The mean condition factor (K) ranged from 1.760 to 2.426 in males and 1.844 to 2.903 in females, while the highest K of 2.903 was observed in the females. Out of 241 stomachs examined in the laboratory, 41 (37.27%) and 43 (32.82%) were empty in males and females respectively, while 69 (62.73%) in males and 88 (67.18%) in females had varied quantities of food. The species was found to be omnivorous feeding on food items that comprised of plant materials, algae, insects, molluscs, crustaceans, fish scales, protozoa, rotifers, detritus, sand, and unidentified food items. The gonado-somatic index (GSI) of the female specimens revealed that the species spawn only one time in a year, from May to August, with peak in May, June, and July. The species had high absolute fecundity ranging from 3,247-28,388 eggs and egg diameter range of 0.5-1.0mm with a mean of 0.7±0.2.
Keywords: Brycinus nurse, Lower Benue River, Food, Fecundity
