Abstract:The aim of this study was to establish the relationship between target strength (TS), dorsal-aspect reflections section and weight, body length of yellow croaker Pseudosciaena crocea (Pc) and black rockfish Sebastes schlegeli (Ss). The results showed that both the weight and body length had the quantitative relationship with the target strength. At 50 kHz, the target strength of different body parts of Pc was between -32.85 and -58.01 dB; at 200 kHz, it was -29.3~-56.99 dB. For the Ss, it was -31.74~-75.87 dB, and -31.74~-74.75 dB, respectively. At both 50 kHz and 200 kHz, the TS of the fish belly was maximal and that of the fish tail was minimal. The correlation between the mean lateral TS and the length was positive, for both 50 kHz and 200 kHz. At 50 kHz: TSPc=24.8 logL (cm)-73.9(side direction); at 200 kHz: TSPc=23.9 logL (cm)-71.3(side direction), and at 50 kHz: TSSs=25.7 logL (cm)-69.16 (side direction); at 200 kHz: TSSs=26.4 logL (cm)-70.8 (side direction). The results of the experiments are expected to provide data support for the design of underwater acoustic monitoring instruments.
