Vertical distribution and mortality of Calanus finmarchicus during overwintering in oceanic waters southwest of Iceland
Vertical distribution and mortality of Calanus finmarchicus during overwintering in oceanic waters southwest of Iceland
复制标题
冰岛西南部海域越冬期间Finmarchicus的垂直分布和死亡率
DOI：
10.1007/s00227-006-0400-7
复制
发表时间：
2007
期刊：
影响因子：
2.4
通讯作者：
P. Reynisson
中科院分区：
文献类型：
--
作者：
A. Gislason;K. Eiane;P. Reynisson
根据1996年11月至1997年6月4次航次的资料，研究了冰岛西南大洋雷克雅尼斯岭样带上Finmarchicus Calanus的季节垂直分布和捕食系统。用1996年11月至1997年4月密度估计值的线性回归估计了越冬期的死亡率。此外，我们还应用垂直表方法估计了4月和6月最古老的人口阶段(C4及以上)的死亡率。在冬季(11月/12月-1月/2月)，这些动物主要生活在大西洋起源的水中，深度为∼300-1500米。向上层的上升主要发生在3月和4月，并一直持续到5月。在所有航次中，都观察到了连续的深层散射层，主要在400-500米到700-800米深度范围内。根据4月份Harstad远洋拖网的采样，散布主要归因于水母(主要是周叶水母)、小型中上层海洋鱼类(除冰盖底栖线虫和Maurolicus muelleri以外的几种)、真甲鱼(主要是褐斑鱼)和对虾(主要是北极龙虾)。这些物种可能对越冬的Finmarchicus构成捕食性威胁。从11月到4月，总数据集的日人均死亡率估计为(平均值为0.004±0.95%CL)0.004±0.0028，冰岛盆地和伊尔明格盆地分别为0.004±0.0033和0.004±0.0023(天-1)。在1997年4月和6月采集的所有样本中，C5/女性和C5/男性的晚年死亡率(平均为0.13%±0.044)和C5/男性的死亡率(0.19%±0.051)高于C4/C5的死亡率(0.00±0.95%CL)。我们讨论了观察到的越冬黄鼠的分布和死亡率与捕食制度的关系。
The seasonal vertical distribution and the predatory regime encountered by Calanus finmarchicus were studied along a transect across the Reykjanes Ridge in the oceanic area southwest of Iceland from data collected during four cruises between November 1996 and June 1997. The mortality for the overwintering period was estimated using linear regressions of density estimates from November 1996 to April 1997. In addition, we also estimated the mortality of the oldest population stages (C4 and older) in April and June by applying the vertical table method. During winter (November/December–January/February), the animals mainly resided at a depth of ∼300–1,500 m in the water of Atlantic origin. Ascent to upper layers took place mainly during March and April, and continued until May. During all cruises, continuous deep-scattering layers were observed, mainly within the range of 400–500 m to 700–800 m depth. Based on sampling with a Harstad pelagic trawl in April, the scattering was mainly ascribed to jellyfish (mainly Periphylla periphylla), small mesopelagic oceanic fishes (several species but Benthosema glaciale and Maurolicus muelleri were most abundant), euphausiids (mainly Meganyctiphanes norvegica) and shrimps (mainly Sergestes arcticus). These species may represent a predatory threat to overwintering C. finmarchicus. From November to April, daily per capita mortality rates were estimated to be (mean ± 95% CL) 0.004 ± 0.0028 for the total data set, and 0.004 ± 0.0033 and 0.004 ± 0.0023 (day-1) for the Iceland Basin and Irminger Basin, respectively. Mortality rates were higher later in life (mean ± 95% CL) for C5/females (0.13 ± 0.044) and C5/males (0.19 ± 0.051) than for C4/C5 (0.00 ± 0.035) when averaged over all samples taken in April and June 1997. We discuss how the observed distribution and mortality rates of overwintering C. finmarchicus might be related to predatory regime.