Hayana, MellyElvyra, RozaYusfiati2013-05-232013-05-232013-05-23Rangga Dwijunanda Putrahttp://repository.unri.ac.id:80/handle/123456789/3455Tapung Hilir river is one of the potential floodplain river ecosystems in Riau Province and the natural habitats of lais danau fish (Ompok hypophthalmus). The purpose of this study is to investigate the reproduction aspects of lais danau fish, that have not been conducted until now. This research was considered as a basic study to provide a solution to some problems that directly effect the production of lais danau fish, such as sexuality, sex ratio, gonad maturity level (TKG), gonad maturity index (IKG) and spawning patterns. The research was conducted during six months from September 2012 to February 2013. Total number of fish obtained was 434, which consist of 185 males and 249 females, sex ratio 1.34: 1. The length of female fish was range between 15.00 to 28.00 cm and it’s weight was range between 10.10 to 108.40 g. Male fish had length from 16.00 to 27,00 cm and weight from 13.80 to 122.50 g. Gonad maturity level found was TKG I to V. The range of length and body weight for females and males of lais danau fish increased on TKG I to IV. Female fishes had average length which was range from 21.83 to 23.02 cm and weight from 58.81 to 60.92 g. The male fishes had average length between from 21.81 to 22.39 cm and weights from 58.82 to 62.87 g. Gonad maturity index (IKG) of female fishes in TKG I-V was ranged from 0.03 to 8.21%, and males from 0.01 to 0.45%. Lais danau fish spawn once in a year, especially at the beginning of the rainy seasonotherReproduction aspectslais danau fish (Ompok hypophthalmus)Tapung Hilir Riverfloodplain riverOther