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| 南极半岛邻近水域南极大磷虾商业捕捞群体的年龄结构时空变化 |
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左涛1, 赵宪勇1, 黄洪亮2, 夏辉3, 徐玉成4, 孙坚强1, 冯春雷2, 王新良1, 朱国平3, 徐鹏翔3, 李灵智2, 陈丹1,3
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1.农业部海洋渔业可持续发展重点实验室 山东省渔业资源与生态环境重点实验室
中国水产科学研究院黄海水产研究所，青岛266071;2.中国水产科学研究院东海水产研究所，上海 200090;3.上海海洋大学， 201306;4.辽宁远洋渔业有限公司，大连 116113
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| 摘要: |
| 2009/2010和2010/2011两渔季，我国渔轮在南极公约区内、位于CCAMLR 48.1亚区邻近南设得兰群岛和48.2亚区邻近南奥克尼群岛的南大西洋水域开展了南极磷虾捕捞作业。根据两渔季采集的捕捞群体中南极大磷虾体长及性比资料，利用体长频数的混合分布法，比较和分析了两渔季我国商业捕捞所获南极大磷虾Euphausia superba Dana的种群年龄结构特点。结果表明，2009/2010和2010/2011渔季夏至秋初（12月~翌年4月），近南极半岛的南设得兰群岛和南奥克尼群岛附近水域，南极大磷虾捕捞群体中至少有5个年龄组，雌雄性比、种群年龄组成存在较为明显的年间和季节、区域差异。48.1亚区近南设得兰群岛水域，2009/2010和2010/2011渔季的1月和12月，南极大磷虾以5+龄虾数量最多，雌性临产个体占相当比例（>40%），雌性临产个体的年龄分布为3+~5+龄，以5+龄为主。而48.2亚区邻南奥克尼群岛的水域，2009/2010渔季的2月，以5+龄虾数量最多，出现一定比例的5+龄雌性临产个体；2010/2011渔季2~4月连续3月，随时间后移，该水域的大磷虾年龄构成由复杂转为单一；以3+龄虾数量最多，雌雄比值增加；雌性临产个体由很少至基本不出现（<1%）；各年龄组生长率随月减少，3~4月均为负值。由上述结果推测，2010/2011渔季南极大磷虾产卵高峰期应早于2011年2月，较2009/2010渔季有所提前。 |
| 关键词: 南极大磷虾 年龄组成 体长频数 混合分布分析 性比 |
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| 基金项目:公益性行业（农业）科研专项（201203018）、农业部“南极海洋生物资源开发利用”和山东省泰山学者“海洋渔业资源与生态”岗项目 |
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| Temporal and spatial variations in age structure of Antarctic krill Euphausia superba （Dana) from commercial fishery in the waters near the Antarctic Peninsular |
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| Abstract: |
| During 2009/2010 and 2010/2011 fishing seasons, Antarctic krill Euphausia superba Dana from the south Atlantic Ocean was harvested by Chinese commercial fishery vessels in the CCAMLR subarea 48.1 near the South Shetland Islands and CCAMLR subarea 48.2 near the South Orkney Islands, respectively. The length-frequency and sex ratio of krill collected in both fishing seasons were analyzed to estimate its growth, age structure, and evaluate potential temporal spatial variations of its spawning season. Based on the results of length frequency fitting mixture distribution, five age groups (1+~5+) were observed in the krill population. The age structure and sex ratio of krill varied in the two fishing seasons and subareas. In the waters near the South Shetland Islands of subarea 48.1, E. superba population was dominanted by individuals at age 5+ in January, 2010 and December, 2011. In the two months, gravid female were abundant and consisted over 40 percent of all krill numbers. Gravid females were between age 3+~5+ and dominated by those of age 5+. In contrast, in the waters near the South Orkney Islands of the subarea 48.2, E. superba population was still dominated by individuals of age 5+ in February, 2010, yet subsequently by those of age 3+ in February, March and April, 2011. Although gravid females of age 5+ were observed, their proportions decreased only about 15% in February, 2010 and less than 1% from February to April, 2011. Monthly observation during February, March and April, 2011 showed that it tended to be fewer gravid individuals, more unimodal age structure and increased sex ratio.In addition, the krill growth rate decreased with month and was negative value in March and April. Based on the above results, it could be inferred that in subarea 48.2，E. superba spawning peak in 2010/2011 fishing season should be earlier than February, 2011, while spawning remained in that month of 2009/2010 fishing season. |
| Key words: Euphausia superba Dana Age structure Length-frequency Fitting mixture distribution Sex ratio |