Virginia Institute of Marine Science, William & Mary, Gloucester Point, VA, USA.
Antarctic Ecosystem Research Division, NOAA, Southwest Fisheries Science Center, La Jolla, CA, USA.
Integr Comp Biol. 2020 Dec 16;60(6):1386-1400. doi: 10.1093/icb/icaa111.
Antarctic krill (Euphausia superba) larval production and overwinter survival drive recruitment variability, which in turn determines abundance trends. The Antarctic Peninsula has been described as a recruitment hot spot and as a potentially important source region for larval and juvenile krill dispersal. However, there has been no analysis to spatially resolve regional-scale krill population dynamics across life stages. We assessed spatiotemporal patterns in krill demography using two decades of austral summer data collected along the North and West Antarctic Peninsula since 1993. We identified persistent spatial segregation in the summer distribution of euphausiid larvae (E. superba plus other species), which were concentrated in oceanic waters along the continental slope, and E. superba recruits, which were concentrated in shelf and coastal waters. Mature females of E. superba were more abundant over the continental shelf than the slope or coast. Euphausiid larval abundance was relatively localized and weakly correlated between the North and West Antarctic Peninsula, while E. superba recruitment was generally synchronized throughout the entire region. Euphausiid larval abundance along the West Antarctic Peninsula slope explained E. superba recruitment in shelf and coastal waters the next year. Given the localized nature of krill productivity, it is critical to evaluate the connectivity between upstream and downstream areas of the Antarctic Peninsula and beyond. Krill fishery catch distributions and population projections in the context of a changing climate should account for ontogenetic habitat partitioning, regional population connectivity, and highly variable recruitment.
南极磷虾（Euphausia superba）幼虫的繁殖和越冬存活率驱动着补充量的变化，而补充量的变化又决定了磷虾丰度的趋势。南极半岛被描述为一个补充热点，也是磷虾幼虫和幼体扩散的潜在重要来源区。然而，还没有对各生命阶段的区域性磷虾种群动态进行空间解析的分析。自 1993 年以来，我们利用 20 年来在南极半岛北部和西部夏季采集的数据，评估了磷虾种群动态的时空格局。我们发现，磷虾幼虫（Euphausia superba 加上其他物种）的夏季分布存在持久的空间分离，这些幼虫集中在大陆斜坡的海洋水域，而 E. superba 补充量则集中在陆架和沿海水域。成熟的 E. superba 雌虾在陆架上的丰度高于斜坡或海岸。磷虾幼虫的丰度在南北极半岛之间相对本地化，且相关性较弱，而 E. superba 的补充量在整个区域通常是同步的。来年，西南极半岛斜坡的磷虾幼虫丰度解释了陆架和沿海水域中 E. superba 的补充量。鉴于磷虾生产力的局部性质，评估南极半岛及其以外的上下游地区之间的连通性至关重要。在气候变化的背景下，磷虾渔业的渔获分布和种群预测应考虑到生活史阶段的栖息地分区、区域种群连通性以及高度可变的补充量。
