2018年夏季南奥克尼群岛南极磷虾集群特征

Aggregation characteristics of Antarctic krill (Euphausia superba) in the South Orkney Islands in summer 2018

  • 摘要: 基于2018年夏季南奥克尼群岛南极磷虾资源声学调查数据,本研究对该海域南极磷虾集群进行了分析。结果显示,检测到南极磷虾集群3 224个,反映集群特征的5个参数即深度、长度、厚度、面积及密度分别为(96.00±64.33) m、(218.52±455.66) m、(11.19±13.98) m、(1 894.40±9 345.72) m2和(114.11±159.60) 尾/m3;不同时间段之间集群密度无显著性差异,但集群深度、长度、厚度及面积之间均存在显著性差异。不同水层间集群厚度和面积之间无显著性差异,但集群深度,长度和密度均存在显著性差异。南极磷虾集群共分为三类,其中第Ⅰ类集群密度最大,为(325.90±221.30) 尾/m3;集群规模最小,为(379.64±433.73) m2;深度最深,为(158.06±67.54) m。第Ⅱ类集群的长度最长,为(1 089.60±1 189.56) m;集群面积为(15 601.25±30 243.33) m2,远大于其他集群。第Ⅲ类集群深度最浅,为(78.91±52.88) m;密度最小,为(48.87±50.33) 尾/m3,但数量最多。

     

    Abstract: Aggregation is a typical behavior of Antarctic krill (Euphausia superba). The distribution and type of aggregation is also the focus of E. superba behavior study. Based on acoustic data collected by E. superba resource survey, the aggregation of E. superba around the South Orkney Islands from January to February 2018 was investigated using the Simrad EK60 (38 and 120 kHz) echosounder. The results indicated that a total of 3 224 E. superba aggregations were detected, and the depth, length, thickness, area and density of E. superba aggregation were (96.00±64.33) m, (218.52±455.66) m, (11.19±13.98) m, (1 894.40±9 345.72) m2, and (114.11±159.60) ind/m3, respectively. In different periods of a day, significant differences were found between depth, length, thickness and area of E. superba aggregations, but density of E. superba aggregation had no significant difference. At different depths of E. superba aggregation, there were significant differences between depth, length, area of E. superba aggregation, but no significant differences were found between thickness and area of E. superba aggregation, respectively. Three types of E. superba aggregation were classified clearly. Type I had the highest density (325.90±221.30) ind/m3, smallest area (379.64±433.73) m2 and deepest depth (158.06±67.54) m; type II had the greatest length (1 089.60±1 189.56) m and the area (15 601.25±30 243.33) m2 was much larger than other two types; type Ⅲ had the smallest depth (78.91±52.88) m and smallest density (48.87±50.33) ind/m3, but it had the greatest number of E. superba in the aggregation.

     

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