The Use of Bridle Line on Operation of Bottom Gill Nets in Manado Bay Waters, North Sulawesi, Indonesia

Abstract

This study was intended to figure out the influence of bridle line application on bottom gill net fishing operations. Bridle line length 1 m in order to prevent the lead line and lower net line to directly touch the bottom waters, and to minimize lifting of pieces of coral and by-catch. Lifting pieces of coral could damage bottom habitats and the benthic organisms. The use of bridle line had resulted the gill net to be environmental friendly and cought only the economically important fish. Bottom gill net used in this study had a size of 148.00 m long and 4.70 m wide and mesh size of 13.75cm with net yarn number 18. It was operated outside of the coral reefs zones at the depth range of 20 m to 50 m. The fish catches were demersal and reef fish with minimum size of 25cm body circle or bigger was dominated by dogtooth tuna, Gymnosarda unicolor. The application of 1 m-bridle line can reduce the coral cover up to 98% compared to the other bottom gill net which its lower part have a direct contact with the seabottom. During 10 fishing trips, there was no benthos brought up to the surface at during the net hauling. But new problem was found that the use of bridle line on the gill net had causes fish escape through the bridle line along the bottom net.