MATURATION AND HISTOLOGY OF THE GONADS OF THREE SELECTED FISH SPECIES OF LOWER RIVER BENUE, BENUE STATE, NIGERIA

The macroscopic and microscopic maturation and histology of the gonads of the three fish species; comprising 189 Hydrocynus forskahlii from Abinsi and 214 from Wadata station, 372 Citharinus citharus from Abinsi and 366 from Wadata, 384 and 363 Mormyrus rume from Abinsi and Wadata, respectively, were caught using gill and cast nets. The specimens were collected fortnightly from fishermen of Lower River Benue, between April 2019 and March 2020. The process of oogenesis and spermatogenesis were studied by macroscopic and microscopic observations, and also utilising histological preparations of ovaries and testes belonging to different gonad maturation stages. The data obtained from this study were subjected to descriptive statistics. The macroscopic and microscopic observations of the fishes gonads corresponded with the method described by Brown-Peterson et al. (2011). There were presences of oocytes at different phases of development indicating the fishes to have prolonged and fractional spawning season, spawning more than once during the spawning season. The histological features corresponding with reproductive cycles and the spawning periods, and the spawning capable phase occurred mostly between May-August. The brooders may be captured during their spawning periods and stocked for aquaculture, or the eggs collected and incubated in the laboratory.