At-sea seabird censuses. Data on the species encountered (including marine mammals), their abundance, distribution and behavior. Data collected aboard cruises off the coast of the Western Antarctic Penninsula, 1993 - 2018.

The objectives of the LTER seabird component during the 92-93 season cruises were similar. These objectives included 1) determining the pelagic abundance and distribution of Adelie Penguins, 2) examining how the physical and biological characteristics of the marine environment influence these parameters and, 3) using these data to identify foraging areas that may be important to Adelie populations being studied as part of land-based work at Palmer Station. Secondary objectives included documenting the abundance and distribution of other seabirds and marine mammals within the LTER study area. The focus of the January cruise was the nearshore foraging habitat, which required sampling at smaller scales. All seabird censuses were thus conducted within approximately 100 kms of Palmer Station while traversing a sampling grid with stations at 10km intervals. The first two days (18-20 January) of this cruise were spent covering the selected grid as rapidly as possible resulting in 45 transects spaced at 45-60 minute intervals. There were no stops at the 10km stations during this Fast Grid phase. Upon completion of the Fast Grid, a force 12 gale suspended data collection for 24 hours. From January 22-25 the grid direction was reversed and the grid repeated. During this Slow Grid phase, 2-M net tows were done at 10km intervals and BOPS and 1-M and 2-M net tows every 20 km. All seabird censuses during the cruise were done using the procedures outlined in the previous paragraph.

Seventy-two 30-minute transects and 15 station censuses were completed during the January cruise. Athough seabirds were widely distributed throughout the study area, the highest densities and greatest biomass occurred consistently within 2-5 km of Anvers Island and several major island groups to the south and
west near the Antarctic Peninsula. Adelie Penguins were the dominant component of this seabird assemblage in terms of both abundance and biomass. South Polar Skuas ranked second and Black-browed Albatross third, with the latter becoming the dominant assemblage member at distances greater than 10km from land. Although
South Polar Skuas had been expected to occur in more pelagic habitats, few were censused at distances greater than 10km from land. The presence of both skuas and penguins so close to land was unexpected. The most important variable accounting for variation in the distribution and abundance of seabirds appeared to
be the location of the 200m contour, which throughout the study area occurred 2-5km from the adjoining land masses. Approximately 65% of the seabirds censused during this cruise (85% of the biomass) occurred in association with this contour.

1992-1993年度航次中，长期生态研究（Long Term Ecological Research, LTER）海鸟子项目的研究目标与同系列航次基本一致。具体研究目标包括：1）明确阿德利企鹅（Adelie Penguin）的远洋丰度与分布格局；2）探究海洋环境的物理、生物学特征如何影响上述参数；3）利用所得数据，识别帕尔默站（Palmer Station）陆基监测所研究的阿德利企鹅种群的关键觅食区域。次要研究目标包括记录LTER研究区域内其他海鸟与海洋哺乳动物的丰度与分布情况。本次1月航次的研究重点为近岸觅食生境，因此需采用小尺度采样方案。所有海鸟普查均在帕尔默站周边约100公里范围内开展，沿间隔10公里设置的采样网格行进。航次前两日（1月18日至20日）以最快速度完成选定采样网格的覆盖作业，共布设45条样线，样线间隔为45至60分钟；此「快速网格」阶段未在10公里间隔的采样站点停靠。快速网格作业完成后，遭遇12级大风，数据采集暂停24小时。1月22日至25日，采样网格方向反转并重复布设；此「慢速网格」阶段中，每间隔10公里开展一次2-M拖网采样，每间隔20公里开展一次BOPS采样及1-M、2-M拖网采样。本次航次所有海鸟普查均采用前文所述的标准化流程开展。本次1月航次共完成72条时长30分钟的样线调查及15个站点的普查工作。尽管海鸟在整个研究区域内广泛分布，但最高种群密度与最大生物量均集中出现在安沃尔岛（Anvers Island）周边2至5公里范围内，以及南极半岛（Antarctic Peninsula）附近南部、西部的几处主要岛群周边。从丰度与生物量来看，阿德利企鹅均为该海鸟群落的优势类群；南极大贼鸥（South Polar Skua）位列第二，黑眉信天翁（Black-browed Albatross）位列第三，其中黑眉信天翁在离岸10公里以上的区域成为群落优势类群。尽管此前预计南极大贼鸥会更多出现在远洋生境中，但在离岸10公里以上区域的普查记录中其数量极少。贼鸥与企鹅如此贴近陆地的分布情况均超出预期。影响海鸟分布与丰度变化的最关键变量为200米等深线的位置——整个研究区域内，200米等深线紧邻陆地块体，二者间距仅2至5公里。本次航次普查得到的海鸟个体中，约65%（生物量占比达85%）均分布在该等深线周边区域。