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.#############

本数据集为ASAC项目465的相关数据元记录，该项目的公开详情可通过下方链接查阅。基于参考文献摘要内容如下：
1. 1992年全年，研究人员通过捕获返回赫德岛（53°05′S，73°30′E）的98只成年王企鹅（King penguin, Aptenodytes patagonicus）的胃容物，分析确定其饮食组成。在两个繁殖生长季中，其饮食以灯笼鱼科鱼类Krefftichthys anderssoni为主，数量占比达94%，生物量占比为48%。裸蜥鱼科鱼类Magnisudis prionosa的数量占比不足1%，但生物量占比达17%。冬末幼雏营养不良且易发生饥饿时，冰鱼Champsocephalus gunnari占幼雏饮食生物量的17%，但其在企鹅全年饮食中的总占比仅为3%。头足类仅在4月至8月被企鹅摄入，其中Martialia hyadesi为最常见的头足类猎物，占冬季饮食的40%~48%。剩余饮食包括头足类Moroteuthis ingens以及除K. anderssoni外的其他鱼类。
投喂给幼雏的混合日粮能量含量随季节波动：生长季最高（7.83±0.25 kJ·g⁻¹），冬季最低（6.58±0.19 kJ·g⁻¹）。通过能量实验估算，1992年繁殖季中，每只成年企鹅需消耗300 kg食物，其中55 kg会传递给幼雏。幼雏在初冬（1.2±0.3 kg）与第二个生长季中期获得大量食物，晚冬时食量最小（0.4±0.1 kg）。据估算，抚育一只王企鹅幼雏所需总能量为724 MJ。本研究还讨论了商业捕捞对王企鹅繁殖活动的潜在影响。

2. 1998-1999年晚孵化期，研究人员通过卫星追踪了麦夸里岛的23只王企鹅，以确定其觅食区与该岛附近拟设立的海洋保护区（Marine Protected Area, MPA）的重叠范围。所有企鹅均朝东离开繁殖群，并顺时针返回岛屿，其中3只在常规觅食区的北部活动，停留于南纬56°以北区域。其余20只企鹅向南行进，多数在返回岛屿前跨越南纬59°。总觅食区估算为156000平方公里，其中36500平方公里为核心觅食区（企鹅在此累计停留时长超过150小时）。向北觅食的企鹅平均距离繁殖群331±24公里，而向南觅食的企鹅平均距离为530±76公里。向南觅食的企鹅平均总行程为1313±176公里，向北觅食的企鹅平均总行程为963±166公里。不仅如此，企鹅的大部分觅食时间均位于拟设立MPA的边界内，且主要活动于高度保护带范围内。因此，至少在孵化期，该海洋保护区有望覆盖王企鹅的觅食区。

3. 研究人员通过卫星遥测、时间深度记录仪及饮食样本，对比了赫德岛与麦夸里岛王企鹅的觅食策略。麦夸里岛与赫德岛的企鹅觅食行程时长分别为16.8±3.6天与14.8±4.1天。麦夸里岛的企鹅总行进距离为1281±203公里，赫德岛的为1425±516公里。麦夸里岛的企鹅海上总停留时间为393±66小时，赫德岛的为369±108小时。麦夸里岛的企鹅深潜次数多于赫德岛种群。麦夸里岛的企鹅日均行进速度为1.5±0.2 km·h⁻¹·day⁻¹，赫德岛的为1.3±0.1 km·h⁻¹·day⁻¹。在麦夸里岛，19%的潜水深度介于70~90米之间，而赫德岛的这一比例为35%。两个种群的主要饮食猎物均为Krefftichthys anderssoni与Moroteuthis ingens。两个种群的海上分布与觅食行为差异，可能与两岛周边的海洋学与水深地形条件有关。饮食差异可能源于猎物可获得性的年际变化，因为两个繁殖群的研究时段虽均为孵化期，但分属不同年份。

4. 研究人员利用15只王企鹅收集的近36000份垂直温度剖面，绘制了新西兰南部海域的海洋锋面分布图。基于企鹅追踪路线上海面150米以内的温度数据推导得出的南极绕极流（Antarctic Circumpolar Current, ACC）锋面位置，与通过海面高度（Sea Surface Height, SSH）地图推断的锋面位置吻合度良好。在这个富涡旋区域，SSH地图中检测到的中尺度特征，也在基于潜水数据得到的单条温度剖面中得到了重现。麦夸里岛王企鹅的觅食策略似乎强烈受海洋学结构影响：几乎所有企鹅的潜水行为均局限于极锋（Polar Front）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，极锋北支构成了一条边界：北侧表层叶绿素浓度较低，南侧则较高。