Acoustic detection and analysis of Acetes chinensis in the adjacent waters of the Daya Bay Nuclear Power Plant

ZENG Lei;CHEN Guobao;WANG Teng;YANG Bingzhong;YU Jie;LIAO Xiuli;HUANG Honghui;South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences;Guangdong Provincial Key Laboratory of Fishery Ecology and Environment;Key Laboratory of Marine Ranch Technology, Chinese Academy of Fishery Sciences;Scientific Observing and Experimental Station of South China Sea Fishery Resources and Environment, Ministry of Agriculture and Rural Affairs;

Daya Bay Nuclear Power Plant;;Acetes chinensis;;resources dynamic;;spatial distribution;;acoustic assessment

To provide a new option for the early warning, prevention, and control of the typical disaster-causing organism Acetes chinensis in the adjacent waters of Daya Bay Nuclear Power Station, an acoustic method, supplemented by a trawl survey and underwater video observation methods, was used to study the dynamics, spatial distribution characteristics, and migration trend of A. chinensis in the survey area from January 11 to 14, 2019. As a result, A. chinensis accounted for more than 99% of the captures collected by trawl samples, along with only a very few jellyfish and fish. Biomass density of A. chinensis estimated by the traditional sweeping area method was significantly higher than that derived from acoustic assessment. They showed a linear regression relationship: Y=2.3419 X–3640.3(Y depicts the result estimated by the traditional sweeping area method and X depicts the result derived from the acoustic assessment). According to in situ acoustic detection, the density of A. chinensis resources fluctuated greatly in different periods(0.56–170.30 m~2/n mile~2). This showed a general trend of first increasing and then decreasing, with the highest value during 22:30–22:40. In the vertical direction, A. chinensis was mainly distributed in the middle and lower waters at 5.2–7.2 m, and there was a clear downward migration trend from 22:50 to 00:10. In the horizontal direction, the biomass densities of A. chinensis in different transects increased gradually from the inside to the mouth of Daya Bay. Combined with dynamic regulation and the underwater video observations of A. chinensis resources in different time periods, it was likely that the A. chinensis would migrate into Daya Bay during 19:00–23:00, and then move back to the mouth of Daya Bay after 23:00. To further confirm this inference, in situ acoustic detection experiments should be conducted simultaneously in the adjacent waters of the Daya Bay Nuclear Power Plant and the mouth of Daya Bay, and the biotic and abiotic environmental factors, such as feed organisms, water temperature, salinity, and current among other factors should be considered comprehensively to further explore the driving mechanism of the horizontal migration of A. chinensis. In conclusion, compared with traditional investigation methods, the acoustic method has many advantages, such as scientific, efficient, and real-time monitoring. Therefore, it can better meet the practical needs of early warning, prevention, and control of cold source biosafety in the Daya Bay Nuclear Power Plant.