声学仪器间干扰信号的消除及其在南极磷虾集群研究中的应用

Removal of the inter-instrument acoustic interference and its application in the study of Antarctic krill swarms

为充分利用渔船采集的声学数据,基于Echoview渔业声学数据后处理软件的相关功能模块,建立了一种强干扰背景下的回波映像集群信号提取方法,并针对2011年2月在南奥克尼群岛周边水域采集的南极磷虾集群数据进行了应用研究,有效消除了回声数据中的强干扰信号。还原后的磷虾集群数据显示,南极磷虾集群具有明显的昼夜垂直移动特征,白天虾群几何中心分布水层的平均深度为77.4 m,虾群平均厚度为10.8 m;夜间分布水层变浅,平均深度为41.2 m,平均厚度为8.8 m。

Collecting acoustic data from fishing vessels is an important trend in fishery resources study,yet the quality of the data may be seriously compromised by inter-instrument acoustic interferences due to the lack of signal synchronization apparatus for onboard acoustic instruments.In order to fully use the contaminated acoustic data,a method of extracting swarm signals from echogram with strong interference was established based on the relevant modules in the Echoview（R）,an acoustic data post-processing software.The methods were then applied to the acoustic data on Antarctic krill collected onboard a fishing vessel operated around South Orkney Islands during February 2011,and the interference was effectively removed from the echogram.Distinct diel vertical migration was observed in the krill swarms.The geometrical center of the krill swarms was distributed in layers with a mean depth of 77.4 m and a mean thickness of 41.2 m in daytime,while the swarms tended to migrate upward nocturnally at a mean depth of 34.9 m and a mean thickness of 8.8 m.