Reproductive Tract Morphometry and Evaluation of Fresh Wild African Catfish (Clarias gariepinus) Milt from Lake Alau, Maiduguri, Nigeria

Abstract

Reproductive morphometry of Clarias gariepinus (C. gariepinus) is essential in distinguishing different species that are closely related to it and adequate  information is required regarding the seasonal variation of milt characteristic of wild species. This study was designed to document the reproductive tract  morphometric dimensions and milt characteristics of wild C. gariepinus during spawning and non-spawning seasons in Lake Alau, Maiduguri,  Nigeria. Sixty male brood stocks were used comprising thirty each for spawning and non-spawning seasons. The reproductive tracts were removed and  their dimensions measured. The milt samples were collected, pooled and evaluated. Results of the study showed that the body weight, sperm  concentration and testicular indices differed significantly (p˂0.05) between the two seasons of evaluation. In addition, a positive correlation (p˂ 0.05)  between body weight of fish and milt volume (r = 0.656 and r = 0.646) was also observed in both seasons. It was concluded that the left testis of C.  gariepinus is heavier, longer and thicker than the right. Nonetheless, the C. gariepinus had larger body weights and higher spermatozoa concentration in  spawning season than in non-spawning season; those with larger body weights had higher volume of milt than those with lower body weights.