Krill demography and large-scale distribution in the Western Indian Ocean sector of the Southern Ocean (CCAMLR Division 58.4.2) in Austral summer of 2006
Krill demography and large-scale distribution in the Western Indian Ocean sector of the Southern Ocean (CCAMLR Division 58.4.2) in Austral summer of 2006
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DOI：
10.1016/j.dsr2.2008.06.014
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发表时间：
2010-05-01
影响因子：
3
通讯作者：
Hosie, Graham W.
中科院分区：
文献类型：
--
作者：
Kawaguchi, So;Nicol, Stephen;Hosie, Graham W.
在2006年1月下旬至2月下旬对南大洋西南印度洋部分进行的一次大规模调查期间，对磷虾的人口统计进行了研究（BROKE-West）。测量从1月下旬的东经30度进展到2月下旬的东经80度，北部以南纬62度为界。根据RMT 8网的渔获量计算，四个地理层的平均磷虾密度为每1000米0.84-68只，总体平均值为每1000米6.7只。对磷虾的分布和种群结构进行了聚类分析和混合分析，结果表明，小型磷虾（众数为25-30 mm）广泛分布于西部中部，中型和大型磷虾（众数分别为35-45 mm和45-55 mm）主要分布于调查区的中、东半部。这些研究结果在所观察到的地理和海洋学结构、大陆坡区、锋面、海流和环流的范围内进行了讨论。四个分层中R1（1岁+招募）的比例招募指数范围为0.089-0.226，R2（2岁+招募）的比例招募指数范围为0.204-0.440。招募分析显示，调查地区的西半部和东半部之间存在差异，这表明可能存在与威德尔环流系统和普拉茨湾环流系统有关的独立的自我维持种群。磷虾幼虫主要观察到沿着的货架休息，这意味着在11月中旬产卵的早期开始。早春发育的一系列滨海湾可能是利用早季浮游植物生长进行早期成熟和产卵的重要生境之一，这些幼虫将被沿岸流沿着陆架坡向西搬运。皇冠版权所有（C）2009由爱思唯尔有限公司出版。保留所有权利。
Krill demography was studied during a large-scale survey of the South Western Indian sector of the Southern Ocean conducted in late January to late February 2006 (BROKE-West). The survey progressed from 30 degrees E in late January to 80 degrees E in late February and was bounded in the North by 62 degrees S. The average krill density calculated from the catches of the RMT 8 net for four geographical strata ranged from 0.84-68 individuals per 1000 m(-3), with overall mean of 6.7 individuals per 1000 m(-3). Krill distribution and its population structure were analysed using cluster and mixture analysis of the length frequency distribution, showing small sized krill (modal size of 25-30 mm) broadly distributed in the centre of the western area whereas middle and large sized krill (modal size of 35-45 mm and 45-55 mm, respectively) mainly distributed in the middle and eastern half of the survey area. These findings are discussed in the context of the observed geographic and oceanographic structures; the continental slope area, fronts, currents and gyres. Proportional recruitment indices ranged 0.089-0.226 for R1 (age 1+ recruitment) and 0.204-0.440 for R2 (age 2+ recruitment) in the four strata. Recruitment analysis revealed differences between western and eastern halves of the surveyed area, suggesting the possible existence of separate self-sustaining populations linked to the Weddell Gyre and Prydz Bay Gyre systems. Krill larvae were mainly observed along the shelf break, implying the early onset of spawning in mid-November. The series of coastal polynyas developing in the early spring may be one of the important habitats allowing use of early season phytoplankton growth for early maturation and spawning, and those larvae would be transported westwards by the coastal current along the shelf slope. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.