Some Aspects of the Biology of African Electric Fish Mormyrus rume Valenciennes, 1846 (Osteoglossiformes; Mormyridae) in Lower River Niger at Idah, Kogi State, Central Nigeria

Aspects of the biology of Mormyrus rume (Valenciennes 1846) in Lower River Niger at Idah, Kogi State, central Nigeria were investigated. This included the length-weight relationship, condition factor and food and feeding habits of the fish species. The major fishing methods employed for collecting the 220 specimens were gillnetting and drag netting. Analysis of stomach content was by numerical, frequency of occurrence and point methods. The length weight relationship was determined using linear correlation and regression analysis. The weight of the fish ranged from14.0g (SL = 12.2cm) to 79.4g (SL = 21.0cm) with mean value of 42.9g (11.5cm S L). The b value is 3.3, 3.2 and 3.2 for male, female and combined sexes respectively. The fish exhibited positive allometric growth. The average condition factor value of 0.93, 0.86 and 0.89 are recorded for the male, female and combined sexes respectively. The low average condition factor recorded in this study is as a result of the fact that the samples studied were post juveniles. The length of the gut in relation to the length of the body was about one third of the body length (1:3).The species fed on animal materials (Chironomous larvae and adult insects). The major food items encountered in the stomachs were majorly zoobenthos of which Chironomous larvae was dominant (commonness field >50)

Aspects of the biology of Mormyrus rume (Valenciennes 1846) in Lower River Niger at Idah, Kogi State, central Nigeria were investigated. This included the length-weight relationship, condition factor and food and feeding habits of the fish species. The major fishing methods employed for collecting the 220 specimens were gillnetting and drag netting. Analysis of stomach content was by numerical, frequency of occurrence and point methods. The length weight relationship was determined using linear correlation and regression analysis. The weight of the fish ranged from14.0g (SL = 12.2cm) to 79.4g (SL = 21.0cm) with mean value of 42.9g (11.5cm S L). The b value is 3.3, 3.2 and 3.2 for male, female and combined sexes respectively. The fish exhibited positive allometric growth. The average condition factor value of 0.93, 0.86 and 0.89 are recorded for the male, female and combined sexes respectively. The low average condition factor recorded in this study is as a result of the fact that the samples studied were post juveniles. The length of the gut in relation to the length of the body was about one third of the body length (1:3).The species fed on animal materials (Chironomous larvae and adult insects). The major food items encountered in the stomachs were majorly zoobenthos of which Chironomous larvae was dominant (commonness field >50)