南极半岛邻近海域长臂樱磷虾的数量分布与生长发育

Distribution and development of Thysanoessa macrurain waters adjacent to the Antarctic Peninsular

利用2010年1月23日～2月13日在南极半岛邻近海域南设得兰群岛(CCAMLR48.1亚区内)和南奥克尼群岛(CCAMLR48.2亚区内)南极大磷虾Euphausia superba Dana渔场采集的浮游动物样品,对长臂樱磷虾Thysanoessa macruraG.O.Sars数量密度、体长分布及发育期组成等进行了研究;样品由330μm浮游生物垂直拖网和500μm表层水平拖网采集。调查海域表层水温范围为0.37～2.49℃,平均1.58℃;盐度范围为32.91～34.32,平均33.88。长臂樱磷虾广泛分布于调查水域;以垂直网样计,48.1亚区的平均密度为261.6ind/1000m3,48.2亚区为391.5ind/1000m3,各站位的分布密度与表层水温呈显著正相关(P=0.04)。长臂樱磷虾由CII期原蚤状幼体至成体间的所有发育期个体组成,以蚤状幼体数量居多;蚤状幼体、未成体及成体的体长范围与平均体长分别为2.74～6.80mm、5.15mm,6.81～16.20mm、8.15mm,15.40～20.70mm、17.98mm。蚤状幼体各期生长率范围为0.013～0.064mm/d,两亚区间无显著差异(P=0.37),各期均值为0.040mm/d;48.1亚区长臂樱磷虾生殖季节的估测结果为9月末～10月,48.2亚区内为10月初～11月中旬。长臂樱磷虾在水平网中的出现频率和个体出现数量均高于垂直网,说明在磷虾水平分布和生长发育研究中,水平拖网可作为垂直拖网的有效补充发挥重要作用。

Based on zooplankton samples collected in Antarctic krill Euphausia superbaDana fishing grounds adjacent to the South Shetland Islands（CCAMLAR subarea 48.1）and South Orkney Islands（CCAMLAR subarea 48.2）in the Antarctic peninsular region during the period of January 23to February 13,2010,the abundance density,length distribution and development stage composition of Thysanoessa macrura G.O.Sars were studied.Samples were collected by two types of plankton nets,one was vertically towed plankton net with 330μm mesh size,and the other was horizontally towed surface plankton net with 500μm mesh size.Sea surface temperature（SST）ranged from 0.37℃to 2.49℃,with a mean of 1.58℃ ;surface salinity ranged from 32.91to 34.32,with a mean of 33.88.T.macrura was found in most of the survey area;vertical sample showed that the mean density was 261.6ind/1000m3in subarea 48.1and 391.5ind/1000m3 in subarea 48.2,and the density was positively correlated to SST（P=0.04）.T.macrura was composed of individuals at all development stages from CII to adults and dominated by furcilia.The range and mean total length of furcilia,juvenile and adult were 2.74～6.80mm,5.15mm;6.81～16.20mm,8.15mm and 15.40～20.70mm,17.98 mm respectively.The growth rate at the various stages of furcilia ranged from 0.013～0.064 mm/d;no significant difference was found between the two subareas（P=0.37）,and the global mean was 0.040mm/d.The spawning season of T.macrura was estimated to be at the end of September to October in subarea 48.1and at the beginning of October to mid November in subarea 48.2.T.macruraappeared more frequently in the surface towed net both in terms of station and in terms of specimen,indicating that the surface towed net can be an effective supplement to the vertically towed net in study of the spatial distribution and growth of krills in general.