Maninjau Lake is located in Tanjung Raya Subdistrict, Agam Regency, West Sumatra Province, with the surface area 9,737.50 ha. Maninjau Lake has one major outlet through the Batang Antokan river flows to the west coast of Sumatra Island. The excessive number of floating net cages, those are upper of carrying capacity, is the biggest problem in Maninjau Lake. Mass fish kills happened frequently due to deterioration of water quality in this lake. This study is aimed to observe the current fishery activities and environmental conditions in Maninjau Lake. The data were collected by survey using interview methods and record statistic data from the government. The results showed that Maninjau Lake has three functions as ecologies, social and economic. The capture fisheries are still using the traditional fishing gears, while the fish culture is using the floating net cages. There were 18 species inhabited in Maninjau Lake, consists of native and introduced species. Moreover, invasive species have been found, namely Pterygolichtys pardalis (Amazon sailfin catfish) and Amphilophus trimaculatus (flowerhorn). Nowadays, it is difficult to catch the native fish, Tor sp (gariang), and the endemic fish, Psilopsis sp (rinuak). Maninjau Lake is in the eutrophic state with quite good waters conditions, but it could become worse since the lake is steadily changing naturally and also anthropogenic activity. The fisheries management in Maninjau Lake should involve the stakeholder groups that have a different degree of interest, the role of management, and related institutions.

One of the economically valuable consumption fish in Ranau Lake is the hampala barb (Hampala macrolepidota). Hampala barb is the top predator in Ranau Lake. The fish population is still quite a lot, but it is starting to decline. This study aimed to determine the reproductive biology of hampala barb in Ranau Lake. Ranau Lake is located in South Sumatra Province and Lampung Province, Indonesia. The research was conducted by the inventory survey method and laboratory analysis. Fish samples were obtained from fisher’s catch, where the fish were caught using gill nets with varying mesh sizes and harpoon. The fish were measured for length body and total weight. Then surgery was performed to determine their reproductive biological characteristics (sex, size of first gonad maturity, gonad maturity stage, Gonad Somatic Index, fecundity, and egg diameter). The results showed that the hampala barb in Ranau Lake laid the eggs throughout the year with a sex ratio of 1: 1, the size of the first stage of gonad maturity of male and female were 15.38 cm and 19.21 cm, fecundity between 17,406-63,793 eggs, and egg diameter between 0.8-1.9 mm. This reproductive biology information can be used for the management of hampala barb in Ranau Lake.