Abstract | Fisheries researchers reveal that many species of native wild fish are threatened with extinction due to uncontrolled fishing, things that can threaten their existence in nature, one of which is in the Banjaran River. The aims of this study were: to determine the quality of fish spermatozoa, to determine the gonadal maturity index (IKG), to determine the Gonad Maturity Level (TKG), and to determine the histological description of the male gonads in order to obtain data for conservation purposes. The research was conducted by survey method, the sample was taken by purposive random sampling technique. The results of the study during the March-May period showed that the sperm quality of Nilem Fish was best in May, which had a milt volume of 0.21 ml, a spermatozoa concentration of 2.3454 x109 cells/ml, Motility 3, and viability of 82.55%. In Brek Fish the highest volume of milt was found in May, namely 0.25 ml, the highest concentration of spermatozoa was in April 34.465 x109 cells/ml, with viability 88.62%, and motility 2.9. The best quality of Lunjar fish sperm was found in May which had a milt volume of 0.02 ml, spermatozoa concentration of 22.435 x109 cells/ml, 80% viability, and motility 3. All sperm samples were white with a pH of 7-8. Based on TKG and IKG, it can be seen that many Nilem fish are found spawning in April and May, Brek and Lunjar fish are found spawning every month. Histological structure of male gonads in Nilem, Brek and Lunjar fish had the same composition, in immature fish the spermatogenic cell composition observed was dominated by spermatocytes, spermatids, and spermatogonia, in mature fish the gonads were dominated by spermatozoa cells. and spermatids, whereas in post-spawning fish spermatozoa and spermatogonia were found in large number. |