Fish spatial distribution and biomass assessment in East Dongting Lake using hydroacoustic method
A SIMRAD EY60 echo-sounder with 200 kHz split-beam transducer was used to survey the fishery resources in East Dongting Lake during July 11—17, 2015. The results showed that the mean target strength ( acoustic reflectivity of target fish) in the surveying navigation section was ( -51. 24 ± 5. 26) dB and the mean length was about 12 cm, ranging from 2 to 125. 8 cm. The fish target strength in different areas was significantly different, which meant there was signifi-cant difference in fish size. The mean fish density was 186. 3 f/1 000m3 , ranging from 1. 223 f/1 000 m3 to 1 534. 2 f/1 000 m3 in all survey navigation sections, where a high fish density occurred in the middle area of East Dongting Lake( CEC navigation section) . The total amount of fish mantissa biomass were estimated at 2. 36 × 108 f, in which the fish with tar-get strength lower than-43 dB ( length about 28 cm) was 95. 5%.
NETL
NSTL
万方数据
维普
