| dc.description.abstract | Lake Toba has considerable fishery resources with various types of fishes utilized by the community, one of them is bilih fish. Bilih fish (Mystacoleucus padangensis) is an endemic fish of Lake Singkarak which was introduced to Lake Toba waters. This study aims to analyse populations, growth patterns, sex ratio, gonad maturity level, gonad maturity index, fecundity and the correlation of bilih fish density with physical and chemical factors in Lake Toba waters. Sampling was carried out on April - May 2024. The sampling stations include the waters of Ajibata, Naborsahan River, Ambarita, and Tiga Raja. Determination of the research location point were determined by using Purposive sampling method based on the activities around the lake. Sampling fish were captured by gill nets measuring 5 meters x 10 meters. Then samples were measured their length and weight and also identified the sex and gonad maturity. Parameters analysis includes the density, the growth patterns, the sex ratio, the gonad maturity level, the gonad maturity index, the fecundity, and the last is the correlation of the bilih fish density to the physical and chemical factors of Lake Toba waters. Based on the research results at the four stations, the highest fish density is found at station 1, the fish growth pattern is allometric positive (b>3) found at station 1 while allometric negative (b<3) found at stations 2, 3, 4. The sex ratio obtain by the number of male fish which is more than female fish, the level of gonad maturity of female bilih fish is more commonly found in TKG III and IV, and the gonad maturity index of female bilih fish has a value of 11.08% - 18.61%, the fecundity of female bilih fish at score of TKG IV which has a value of 11,430 - 16,554 eggs. Among all the physicochemical factors in Lake Toba, the phosphate level has a very strong influence on the density of bilih fish. | en_US |
