Application of hydroacoustics to investigate the distribution, diel movement, and abundance of fish on Zhubi Reef, Nansha Islands, South China Sea

A combination of traditional fish sampling methods (hand-line and gill net) and modern hydroacoustic techniques were used to study fish community structure, distribution, and diel movements of fish on Zhubi Reef to enhance understanding of the ecosystem. We collected 126 individuals from 29 species, 20 genera, 17 families, three orders, and two classes using traditional gear. Perciforms were the dominant group in terms of species richness and biomass. The acoustic data indicated that very small (target strength [TS], dB) -55 dB). The number of single-target detections was significantly higher during the night than during the day (P