Feeding Ecology of Penguins at Heard Island with Special Emphasis on King Penguins

Metadata record for data from ASAC Project 465See the link below for public details on this project.From the abstracts of the referenced papers:#############The diet composition of King penguins Aptenodytes patagonicus at Heard Island (53deg 05S; 73 deg 30E) was determined from stomach contents of 98 adults captured as they returned to the island throughout 1992. During the two growth seasons, the diet was dominated by the myctophid fish Krefftichthys anderssoni (94 % by number, 48 % by mass). The paralepidid fish Magnisudis prionosa contributed less than 1 % by numbers but 17 % by mass. Mackerel icefish Champsocephalus gunnari accounted for 17 % by mass of chick diet in late winter, when chicks were malnourished and prone to starvation, although its annual contribution to the penguins diet was only 3 %. Squid was consumed only between April and August; Martialia hyadesi was the commonest squid taken, comprising 40 to 48 % of the winter diet. The remainder of the diet consisted of the squid Moroteuthis ingens and fish other than K. anderssoni. The energy content of the diet mix fed to the chicks varied seasonally being highest during the growth seasons (7.83 plus or minus 0.25 kJ.g-1) and lowest in winter (6.58 plus or minus 0.19 kJ.g-1). From energetic experiments we estimated that an adult penguin consumed 300 kg of food each of which its chick received 55 kg during the 1992 season. The chicks received large meals at the beginning of winter (1.2 plus or minus 0.3 kg) and during the middle of the second growth season (1.2 plus or minus 0.3 kg), and their smallest meals in late winter (0.4 plus or minus 0.1 kg). The gross energy required to rear a King penguin chick was estimated to be 724 MJ. The potential impact of commercial fisheries on the breeding activities of King penguins is discussed.#############23 king penguins (Aptenodytes patagonicus) from Macquarie Island were tracked by satellite during the late incubation period in 1998-1999 to determine the overlap in the foraging zone of king penguins with an area to be declared a marine protected area (MPA) near the island. While all penguins left the colony in an easterly direction and travelled clockwise back to the island, three penguins foraged in the northern parts of the general foraging area and stayed north of 56 south. The remaining 20 penguins ventured south and most crossed 59 south before returning to the island. The total foraging area was estimated to be 156,000 square kilometres with 36,500 square kilometres being most important (where penguins spend greater than 150 hours in total). North-foraging penguins reached on average 331 plus or minus 24 kilometres from the colony compared to 530 plus or minus 76 kilometres for the south-foraging penguins. The latter travelled an average total distance of 1313 p lus or minus 176 kilometres, while the northern foragers averaged 963 plus or minus 166 kilometres. Not only did the penguins spend the majority of their foraging time within the boundaries of the proposed MPA, they also foraged chiefly within the boundaries of a highly protected zone. Thus, the MPA is likely to encompass the foraging zone of king penguins, at least during incubation.#############The foraging strategies of king penguins from Heard and Macquarie islands were compared using satellite telemetry, time-depth recorders and diet samples. Trip durations were 16.8 plus or minus 3.6 days and 14.8 plus or minus 4.1 days at Macquarie and Heard islands, respectively. At Macquarie Island, total distances travelled were 1281 plus or minus 203 km compared to 1425 plus or minus 516 km at Heard Island. The total time the penguins spent at sea was 393 plus or minus 66 h at Macquarie Island and 369 plus or minus 108 h at Heard Island. The penguins from Macquarie Island performed more deep dives than those from Heard Island. King penguins from Macquarie Island travelled 1.5 plus or minus 0.2 km h-1 day-1 compared to 1.3 plus or minus 0.1 km h-1 day-1. At Macquarie Island, 19% of dives were up to 70-90 m depth compared to 35% at Heard Island. The main dietary prey species were the fish Krefftychthis anderssoni and the squid Moroteuthis ingens in both groups. The differences in the at-sea distribution and the foraging behaviour of the two groups of penguins were possibly related to differences in oceanography and bathymetric conditions around the two islands. Dietary differences may be due to interannual variability in prey availability since the two colonies were studied during incubation but in different years.#############Nearly 36,000 vertical temperature profiles collected by 15 king penguins are used to map oceanographic fronts south of New Zealand. There is good correspondence between Antarctic Circumpolar Current (ACC) front locations derived from temperatures sampled in the upper 150m along the penguin tracks and front positions inferred using maps of sea surface height (SSH). Mesoscale features detected in the SSH maps from this eddy-rich region are also reproduced in the individual temperature sections based on dive data. The foraging strategy of Macquarie Island king penguins appears to be influenced strongly by oceanographic structure: almost all the penguin dives are confined to the region close to and between the northern and southern branches of the Polar Front. Surface chlorophyll distributions also reflect the influence of the ACC fronts, with the northern branch of the Polar Front marking a boundary between low surface chlorophyll to the north and elevated values to the south.#############本元数据记录源自ASAC 465号项目（ASAC Project 465），该项目的公开详情可通过下述链接查阅。以下为所引用论文的摘要内容：#############赫德岛（Heard Island，53°05′S；73°30′E）的王企鹅（King penguin, Aptenodytes patagonicus）的饮食组成，通过1992年全年捕获的98只返岛成鸟的胃容物分析确定。在两个生长季中，其饮食以灯笼鱼科（Myctophidae）鱼类克氏灯笼鱼（Krefftichthys anderssoni）为主，按数量占比达94%，按质量占比达48%。帆蜥鱼科（Paralepididae）鱼类Magnisudis prionosa的数量占比不足1%，但质量占比达17%。马鲛冰鱼（Mackerel icefish, Champsocephalus gunnari）在晚冬时节雏鸟营养不良且易饥饿时，其质量占雏鸟饮食的17%，但其全年在企鹅饮食中的占比仅为3%。鱿鱼仅在4月至8月间被摄食，其中武装鱿（Martialia hyadesi）为最主要的被捕食鱿鱼类群，占冬季饮食的40%~48%。饮食剩余部分由英根滑柔鱼（Moroteuthis ingens）以及除克氏灯笼鱼外的其他鱼类构成。投喂给雏鸟的混合饮食的能量含量随季节变化：生长季时最高，为（7.83±0.25）kJ/g，冬季时最低，为（6.58±0.19）kJ/g。通过能量实验估算，1992年繁殖季中，每只成年企鹅消耗300 kg食物，其中55 kg被雏鸟获得。雏鸟在初冬（1.2±0.3 kg）和第二个生长季中期（1.2±0.3 kg）获得较大份量的食物，而在晚冬时获得的食物最少，仅为（0.4±0.1）kg。饲养一只王企鹅雏鸟所需的总能量估算为724 MJ。本文还讨论了商业渔业对王企鹅繁殖活动的潜在影响。#############1998-1999年的晚孵化期，研究人员通过卫星追踪了来自麦夸里岛（Macquarie Island）的23只王企鹅，以确定王企鹅的觅食区与该岛附近拟划为海洋保护区（Marine Protected Area, MPA）的区域的重叠范围。所有企鹅均向东离开繁殖群，并沿顺时针方向返回岛屿，其中3只在常规觅食区的北部觅食，停留于南纬56°以北区域；其余20只则向南行进，其中多数在返回岛屿前越过了南纬59°。总觅食区估算为156000平方千米，其中36500平方千米为核心觅食区（企鹅在此区域累计停留时长超过150小时）。向北觅食的企鹅平均距离繁殖群331±24千米，而向南觅食的企鹅平均距离为530±76千米。向南觅食的企鹅总行进距离平均为1313±176千米，向北觅食的企鹅则平均为963±166千米。企鹅不仅多数觅食时间处于拟划MPA的边界内，还主要在高度保护区域的边界内觅食。因此，至少在孵化期，该MPA有望覆盖王企鹅的觅食区。#############研究人员通过卫星遥测、时间深度记录仪以及饮食样本，对比了来自赫德岛与麦夸里岛的王企鹅的觅食策略。麦夸里岛与赫德岛的企鹅觅食行程时长分别为16.8±3.6天和14.8±4.1天。麦夸里岛的企鹅总行进距离为1281±203千米，赫德岛的则为1425±516千米。麦夸里岛的企鹅在海上的总时长为393±66小时，赫德岛的为369±108小时。麦夸里岛的企鹅比赫德岛的企鹅进行了更多的深潜。麦夸里岛的王企鹅行进速度为1.5±0.2 km·h⁻¹·d⁻¹，赫德岛的则为1.3±0.1 km·h⁻¹·d⁻¹。麦夸里岛有19%的潜水深度达到70~90米，而赫德岛的这一比例为35%。两个种群的主要捕食猎物均为克氏灯笼鱼（Krefftichthys anderssoni）和英根滑柔鱼（Moroteuthis ingens）。两个种群的企鹅在海上分布与觅食行为上的差异，可能与两岛周边的海洋学与水深地形条件差异有关。由于两个繁殖群的研究均在孵化期进行，但年份不同，饮食差异可能源于猎物可获得性的年际变率。#############研究人员利用15只王企鹅收集的近36000份垂直温度剖面，绘制了新西兰南部的海洋锋面分布图。基于企鹅轨迹上海表150米内的温度数据得到的南极绕极流（Antarctic Circumpolar Current, ACC）锋面位置，与通过海面高度（Sea Surface Height, SSH）图推断的锋面位置具有良好的一致性。在这个多涡区域的SSH图中检测到的中尺度特征，也在基于潜水数据得到的单个温度剖面中得到了重现。麦夸里岛王企鹅的觅食策略似乎受到海洋学结构的强烈影响：几乎所有企鹅的潜水都局限于极锋南北分支之间及其附近区域。表层叶绿素分布也反映了ACC锋面的影响，极锋的北分支构成了北部低表层叶绿素与南部高表层叶绿素之间的边界。