Food Habits and Ecological Niche of Silver Barp Fish (Barbonymus gonionotus) in Jatibarang Reservoir, Semarang

Abstract

Research about biological characteristics of fish is important to support the conservation of fish resources. The fish population in the Jatibarang Reservoir includes Tilapia, Milkfish, Koan, Red Devil, and Silver Barp Fish (local name is tawes). The aims of this research was to study the abundance of plankton and determine the food habits of Silver Barp (Barbonymus gonionotus), such as Index of Preponderance (IP), proportion of food type (Pi) and ecological niche. it can be used as a management reference to maintened tawes, which is native to the waters of the Jatibarag Reservoir. This research was conducted by taking samples of Silver Barp using gillnet and hook fishing gear. Samples were taken in July and November 2020. The results showed that Chlorophycea is the main food for tawes fish (IP value 52.34%). The phytoplankton in the waters of the Jatibarang Reservoir has abundance of 4200 ind / L with the highest abundance is Chlorophyceae with value of 1780 ind / L (42.38%). Based on the results, Tawes chose food from the Cyanopyceae, Dinophyceae and Zygnematophyceae classes however Dictyochophyceae were not found in the digestive contents of the Tawes. The area of the Tawes niche (Bi) was 2,825, with the largest Pi originating from Chlorophyceae plankton while the smallest Pi is from the class Dictyochophyceae and Fragilariophyceae with a value of 0. (Bi) index is to compare the area of the niche with other fish in a habitat, the higher this value means the wider the type of feed.