Mesoscale structure and oceanographic determinants of krill hotspots in the California Current: Implications for trophic transfer and conservation
Mesoscale structure and oceanographic determinants of krill hotspots in the California Current: Implications for trophic transfer and conservation
复制标题
加州洋流磷虾热点的中尺度结构和海洋学决定因素：对营养转移和保护的影响
DOI：
10.1016/j.pocean.2011.04.002
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发表时间：
2011
影响因子：
4.1
通讯作者：
J. Field
中科院分区：
文献类型：
--
作者：
J. Santora;W. Sydeman;I. Schroeder;B. Wells;J. Field
磷虾（磷虾科甲壳类动物）是加州洋流和全球其他大型海洋生态系统中大量鱼类、鸟类和海洋哺乳动物的重要猎物。在这项研究中，我们检验了磷虾的中尺度空间组织与沿海上升流相关的海洋条件有关的假设。为了验证这一点，我们根据 2000 年至 2009 年每年 5 月至 6 月加利福尼亚州附近海域的水声调查（2007 年缺失）编制了磷虾分布气候学。对大约 53,000 平方公里的海洋栖息地进行了采样，形成了从南加州湾到门多西诺角的综合地理空间数据集。我们确定了八个确定的和两个可能的磷虾丰度“热点”的位置和特征。方向依赖性分析表明，磷虾热点方向为西北-东南（135°）方向，对应于200-2000m等深线的各向异性。磷虾热点与三个上升流中心（阿雷纳角、苏尔角和康塞普申角）无关（负相关），这表明磷虾可能会避开近海运输较强的位置或在这些位置的下游聚集。虽然当前的渔业管理认为整个海岸到 2000 米等深线是该生态系统中磷虾的关键栖息地，但我们在此建立了这一关键的中营养级猎物资源的较小规模的结构。确定中尺度磷虾热点及其海洋学决定因素具有重要意义，因为这些较小的生态系统分区可能需要保护，以确保关键的生态系统功能（即营养转移）和恢复力。此外，描绘和量化磷虾热点对于保护该系统中的磷虾捕食者可能很重要。
Krill (crustaceans of the family Euphausiacea) comprise an important prey field for vast array of fish, birds, and marine mammals in the California Current and other large marine ecosystems globally. In this study, we test the hypothesis that mesoscale spatial organization of krill is related to oceanographic conditions associated with coastal upwelling. To test this, we compiled a climatology of krill distributions based on hydroacoustic surveys off California in May–June each year between 2000 and 2009 (missing 2007). Approximately 53,000km of ocean habitat was sampled, resulting in a comprehensive geo-spatial data set from the Southern California Bight to Cape Mendocino. We determined the location and characteristics of eight definite and two probable krill “hotspots” of abundance. Directional-dependence analysis revealed that krill hotspots were oriented in a northwest–southeast (135°) direction, corresponding to the anisotropy of the 200–2000m isobath. Krill hotspots were disassociated (inversely correlated) with three upwelling centers, Point Arena, Point Sur, and Point Conception, suggesting that krill may avoid locations of strong offshore transport or aggregate downstream from these locations. While current fisheries management considers the entire coast out to the 2000m isobath critical habitat for krill in this ecosystem, we establish here smaller scale structuring of this critical mid-trophic level prey resource. Identifying mesoscale krill hotspots and their oceanographic determinants is significant as these smaller ecosystem divisions may warrant protection to ensure key ecosystem functions (i.e., trophic transfer) and resilience. Furthermore, delineating and quantifying krill hotspots may be important for conservation of krill-predators in this system.