Winter Foraging Locations Of Southern Ocean Predators - sub-Antarctic islands 2008/09

Metadata record for data expected from ASAC Project 2940 See the link below for public details on this project.

Public:
The extent of Antarctic winter sea-ice influences all aspects of the Antarctic marine food-web. We will use natural variations in inter-annual ice extent, to assess how a key component of that ecosystem, the predators, use the sea ice zone. Core foraging areas and dietary signals for a key Antarctic predator (Antarctic fur seal) will be identified. We will use newly developed, technology to track the animals, and stable isotopes to examine tropic linkages. Combined with satellite-derived sea-ice data, this will lead to the development of a model to predict how changing sea-ice patterns will influence Antarctic marine predator communities.

Project Objectives:
1. Use large samples of newly-developed (and tested) animal-borne miniature geolocating light level recorders to population level information on the spatial extent of movements of Antarctic fur seals, thereby quantifying the extent of the use of the winter pack-ice and associated waters by these abundant predators.
2. To quantify how changes in winter ice extent influence the location of core foraging areas for this species.
3. To develop models to investigate how changing ice conditions in the future will influence the movements of this species and to examine a range of climate-change scenarios.

Taken from the 2007-2008 Progress Report:
No field work was conducted at Macquarie Island in the last 12 months. This was due to the decision by the state government to not issue permits for the work.

With the help of our colleagues from BAS we did however manage to deploy 20 GLS light loggers on Antarctic fur seals at South Georgia.

Taken from the 2008-2009 Progress Report:
Objective 1 has been revised to the study of Antarctic fur seals only (see below). Research is progressing well with 78 animals tracked in 2008 and a further 80 expected in 2009.
Objectives 2 and 3 will follow once field data is available for both years (May 2010).
Isotopic analysis of blood and whisker samples for the 2008 season will commence in May 2009 once samples have been received.

Taken from the 2010-2011 Progress Report:
Public summary of the season progress:
This study has quantified the response of the Antarctic fur seal (Arctocephalus gazella) to inter-annual variation in oceanographic and winter ice conditions. We have measured the winter spatial foraging patterns of 66 adult females from three circum-Antarctic populations over two years (2008, 2009) during 114 trips to sea, while simultaneously recording in situ water temperature. Stable isotope analysis of fur seal blood and whisker samples indicates that adult females feed on a range of lower (krill) to higher (fish and squid) trophic levels across their winter range. Broad-scale habitat preferences across the range of the species indicate the importance of shelf, ice edge, frontal and oceanic and continental upwelling features in determining winter foraging movements. Quality: Values provided in spatial and temporal coverage are approximate only.

Taken from the 2008-2009 Progress Report:
Variations to work plan or objectives:
Since the original submission of the proposal the project has undergone a change of focus due to logistic constraints imposed by the vertebrate pest eradication plan at Macquarie Island. The revised project objectives now relate to the influences of climate and oceanographic variability including changes in sea-ice extent, on the winter foraging behaviour and habitat use of the Antarctic fur seal, a numerous component of the Antarctic foodweb. Research is being undertaken at three sites with the collaboration of UK, US and South African scientists.

The changes necessitate a reduction in the power of predictions pertaining to Southern Ocean trophic models. However the project will provide much needed insight into the winter behaviour of one of Antarctica's most numerous marine predators.

Field work:
In 2007/8, 78 geolocation light loggers were deployed on adult Antarctic fur seals at three sub-Antarctic/Antarctic sites: South Georgia (n=30), Cape Shirreff (n=18) and Marion island (n=30). Blood and whisker samples were collected for each individual at deployment and on return to facilitate analysis of winter prey consumption.

Laboratory activity/analysis:
Currently whisker samples are being readied for isotopic analysis.

ASAC项目2940预期数据集的元数据记录，如需查看该项目的公开详情，请点击下方链接。

Public:
南极冬季海冰的覆盖范围会影响南极海洋食物网的各个环节。本项目将利用海冰覆盖范围的年际自然变化，评估该生态系统的核心组成部分——捕食者如何利用海冰区域。研究将明确一种关键南极捕食者——南极海狗（Antarctic fur seal）的核心觅食区域与膳食信号。团队将采用新型追踪技术对该物种进行定位，并通过稳定同位素（stable isotope）分析探究其营养级联系。结合卫星反演海冰数据（satellite-derived sea-ice data），本项目将构建模型，预测海冰格局变化对南极海洋捕食者群落的影响。

Project Objectives:
1. 利用大量新型（已验证）的动物搭载式微型光照定位记录仪，获取南极海狗种群移动范围的空间分布数据，从而量化这类优势捕食者对冬季浮冰及相关海域的利用程度。
2. 量化冬季海冰范围变化对该物种核心觅食区域位置的影响。
3. 构建模型，探究未来海冰条件变化对该物种移动行为的影响，并评估一系列气候变化情景下的结果。

Taken from the 2007-2008 Progress Report:
过去12个月内，麦夸里岛（Macquarie Island）未开展任何野外工作。原因是当地州政府未签发该项目的作业许可。
得益于英国南极调查局（BAS）同事的协助，团队仍在南乔治亚岛（South Georgia）的南极海狗身上成功部署了20台GLS光照定位记录仪（GLS light logger）。

Taken from the 2008-2009 Progress Report:
研究目标1已修订为仅针对南极海狗的研究（详见下文）。项目进展顺利：2008年共追踪了78只个体，2009年预计再追踪80只。
待获取两年的野外数据后（预计2010年5月），将推进目标2与目标3的研究。
2008年度采集的血液与触须样本的同位素分析，将在2009年5月收到样本后启动。

Taken from the 2010-2011 Progress Report:
本季度进展公开摘要：
本研究已量化南极海狗（Antarctic fur seal，Arctocephalus gazella）对海洋学与冬季海冰条件年际变化的响应。研究团队在2008至2009年的两年间，对环南极三个种群的66只成年雌性海狗进行了追踪，共完成114次出海航行，同步记录了原位海水温度。对海狗血液与触须样本的稳定同位素分析显示，成年雌性海狗在冬季活动范围内的摄食营养级跨度较大，从较低的磷虾（krill）到较高的鱼类与头足类。该物种大范围的栖息地偏好表明，大陆架、冰缘、锋面、海洋上升流与大陆上升流等环境特征，是决定其冬季觅食移动路径的关键因素。备注：空间与时间覆盖范围所提供的数据仅为近似值。

Taken from the 2008-2009 Progress Report:
工作计划与研究目标调整说明：
自项目提案首次提交以来，受麦夸里岛脊椎动物灭杀计划带来的后勤限制影响，本项目的研究重点发生了变更。修订后的项目目标聚焦于气候与海洋学变量（包括海冰范围变化）对南极海狗——南极食物网中的优势类群——冬季觅食行为与栖息地利用的影响。本研究将在三个站点开展，合作方包括英国、美国与南非的科学家。
此次调整导致南大洋营养模型的预测精度有所降低，但本项目仍将为了解南极最优势的海洋捕食者之一的冬季行为提供亟需的研究视角。

野外工作：
2007/2008年度，研究团队在三个亚南极/南极站点的成年南极海狗身上部署了78台光照定位记录仪：南乔治亚岛（n=30）、开普谢尔夫（Cape Shirreff，n=18）与马里恩岛（Marion Island，n=30）。在部署时与个体返回后，研究人员均采集了每只海狗的血液与触须样本，以便分析其冬季猎物摄入情况。

实验室工作与分析：
目前触须样本已准备就绪，将开展同位素分析。