2010/2011年夏季南设得兰群岛北部南极磷虾体长时空分布特征

利用我国大型拖网渔船渔业科学观察员收集的南极磷虾体长数据,将研究区域划分成经纬度10’×10’小尺度单元,分析了南极磷虾体长分布的时空特征。结果表明,24个单元的平均体长范围为46.9～55.0 mm,其中最小体长为26.8 mm,最大体长为62.2 mm,各单元间体长分布之间存在显著性差异。在纬度方向,各单元南极磷虾体长分布均存在显著性差异;在经度方向,大部分单元(71.4%)南极磷虾体长分布存在显著性的差异。一半以上(60.3%)的样本分布于40～80 m水层。6个水层间(0～120 m,20 m为间隔),南极磷虾体长分布存在极显著的差异,但各水层南极磷虾平均体长较接近(52.5～53.6 mm)。12月,南极磷虾体长范围为26.8～62.4 mm,平均体长为53.1 mm;1月,体长范围为39.1～62.0 mm,平均体长为52.4 mm。12月中旬明显存在一定数量的小个体南极磷虾,优势体长为32～35 mm,约占总数的10%。

The spatial-temporal characteristics of length distribution for Antarctic krill(Euphausia superba) in the northern South Shetland Islands in the austral summer during 2010/2011 fishing season

Using the length data of Antarctic krill collected by the fishery observers on board the large-scale otter midwater trawlers,the present study analyzes the spatial-temporal characteristics of length distribution of Antarctic krill based on dividing the study area into small scale units with resolution of 10′ and 10′.The results show that,the range of average length is 46.9 to 55.0 mm in the 24 units,the minimum and maximum length is 26.8 mm and 62.2 mm,respectively.Significant difference can be found among the units for the length distribution.Remarkable differences of the length distribution also exist for all units on the same latitudinal level and most units(71.4%) on the same longitudinal level.Over half of samples(60.3%) are distributed in the layer under the surface 40 to 80 m.Significant difference can be found for the length distribution among the 6 layers(0 to 120 m with 20 m interval),however,the average length is closer among the layers(52.5 to 53.6 mm).The range of length distribution and average length are 26.8 to 62.4 mm and 53.1 mm in December and 39.1 to 62.0 mm and 52.4 mm in January.Small individuals exist significantly in the middle of December,and the dominant length ranged from 32 to 35 mm,accounting for about 10%.