Estimate of Catches and Calculation of Gillnet Construction in Ulu Benteng Subdistrict, Indonesia

Abstract

The construction design of fishing gear is strongly influenced by the environmental conditions of the waters where it is operated. This study tends to describe the design and construction of gillnets, analyze the composition and proportion of gillnet catches, and evaluate the construction calculations of the gear. The results describe the structure of a fixed gillnet consisting of several main components, including the net body, upper ropes, floats, and weights. The catch composition consisted of twelve fish species dominated by Asian redtail catfish (Hemibagrus nemurus), followed by blue sheatfish (Kryptopterus kryptopterus), Waanders' barb (Puntioplites waandersi), and several other species such as marble goby, grayfish, tongue sole, and various catfish species. Overall, the catch was largely dominated by freshwater catfish groups, indicating the suitability of gillnets for capturing demersal and benthopelagic species in the study area. The results of the gillnet construction calculations showed a shortening value of 57.13%, a net height of 3.8m, and a net area of 172.8m². The buoyancy and sinkage analysis indicated that the floatation and weighting system was balanced and able to maintain the optimal vertical position of the net in the water column. These findings suggest that the current gillnet construction is technically appropriate for local fishing conditions and contributes to an improved understanding of gear performance in inland fisheries.