Bering Sea Benthic Amphipod Community: Stability/Instability Relative to Changing Oceanographic Conditions and Increased Gray Whale Predation

白令海北方端足类床面积约4万km ~ 2，是目前已知最具生产力的底栖生物群落。端足类是灰鲸的主要猎物，东太平洋（加州）鲸鱼种群的很大一部分在白令海北方觅食。尽管自1980年以来灰鲸的数量一直以每年3.29%的速度增长，但去年鲸鱼的死亡率增加了三倍多。有人认为，死亡率的增加可能是由于饥饿。在1986-1988年间，片脚类动物的次级生产量下降了30%，这表明当时鲸鱼可能已经接近白令海片脚类动物群落的承载能力。如今，它们的食物可能有限，除了鲸鱼捕食外，端足类动物产量、丰度和生物量的下降可能是由于初级生产减少或浮游植物种类组成发生变化，导致流向海底的碳通量下降。此外，由于最近的厄尔尼诺事件或全球变暖引起的温度变化也可能影响双头绦虫种群。这项工作将重新使用1986年至1988年使用相同技术取样的台站。具体而言，它将测量的丰度，生物量，大小组成，物种组成和生产的ampeliscid片脚类群落在奇里科夫盆地，北方白令海。这些测量将允许记录1988年至2001年间灰鲸摄食状况可能发生的变化。由于它们的低生长率和长世代时间，双头绦虫群落可能会缓慢地从丰度、生物量和产量的大幅下降中恢复过来。鉴于其核心作用，在能量转移到顶端捕食者，片足类动物生产的下降，无论是什么原因，很可能会改变生态群落结构的奇里科夫盆地。这种变化不仅可能影响该地区的野生动物和鱼类资源，而且可能对西伯利亚和阿拉斯加的土著生计社区产生负面影响。

AbstractThe northern Bering Sea ampeliscid amphipod bed, covering approximately 40,000 km2, is the most productive benthic community reported. Ampeliscid amphipods are the major prey of gray whales and a significant proportion of the eastern Pacific (California) whale population feeds in the northern Bering Sea. Although the gray whale population has been growing at a rate of 3.29%/yr since 1980, there has been over a three-fold increase in whale mortality in the last year. It has been suggested that this increase in mortality may be due to starvation. A 30% decline in amphipod secondary production between 1986-1988 indicated that the whales may have been approaching the carrying capacity of the Bering Sea amphipod community at that time. Today, they may be food limited.In addition to whale predation, declines in amphipod production, abundance and biomass could be due to a decrease in primary production or changes in phytoplankton species composition, resulting in declines of carbon flux to the seabed. In addition, a temperature regime shift due to recent El Nino events or global warming might also impact ampeliscid populations. This effort will reoccupy stations sampled from 1986 to 1988, using identical techniques. Specifically, it will measure the abundance, biomass, size composition, species composition and production of the ampeliscid amphipod community in the Chirikov Basin, northern Bering Sea. These measurements will permit documention of changes that may have occurred in the feeding regime of the gray whales between 1988 and 2001. Due to their low growth rates and long generation times, the ampeliscid community may be slow to recover from substantial declines in abundance, biomass and production. Given their central role in energy transfer to apex predators, declines in amphipod production, whatever the cause, are likely to alter the ecological community structure in the Chirikov Basin. Such changes may effect not only wildlife and fish resources in the region, but may also negatively impact the native subsistence communities in both Siberia and Alaska.