Distribution of foraging effort of Antarctic fur seals in relation to oceanographic features around Heard and Kerguelen Islands

Metadata record for data from ASAC Project 1251 See the link below for public details on this project.

---- Public Summary from Project ----
The aim of this study is to develop spatial GIS models of fur seal foraging density over the Kerguelen Plateau that will enable a rapid assessment method for identifying areas of high conservation value for Marine Protected Area planning and management. These models will be based on data on fur seal foraging densities in the HIMI region, and oceanographic data on bathymetry, sea-surface temperature and ocean colour (primary productivity).

From the abstract of the referenced paper:

We investigated the spatial and temporal distribution of foraging effort by lactating Antarctic fur seals Arctocephalus gazella at Heard Island using satellite telemetry and time-depth recorders. Two principal diving types were identified: 'deep' dives averaging 48.6 m, and 'shallow' dives averaging 8.6 m. Discriminant function analyses were used to assign dives based on their depth and duration. Generalised linear mixed-effects models of night dives (greater than 80% of all dives) indicated both spatial and temporal effects on the distribution of deep and shallow dives. Deep dives were more common in the deeper shelf waters of the Kerguelen Plateau, and these dives predominantly occurred after sunset and before sunrise. In contrast, shallow dives were more common in slope waters on the southeastern margin of the Kerguelen Plateau in the hours either side of local midnight. We suggest that these 2 distinct diving types reflect the targeting of channichthyid (deep dives) and myctophid (shallow dives ) fish, and are indicative of spatial and temporal differences in the availability of these 2 important prey groups. We also identified 3 distinct behavioural dive groups (based on multidimensional scaling of 19 diving and foraging trip parameters) that also differed in their spatial distribution and in their relative importance of deep and shallow dives. The present study provides some of the first evidence that diving strategies are not only influenced by where foraging takes place, but also when.

The fields in the campaign_41_tracks.csv file are:

campaign_id (the campaign identifier: aadc_campaign_41)
animal_id (the identifier of the individual animal)
scientific_name (scientific name: Arctocephalus gazella)
ptt_id (the identifier of the PTT device on the animal. Note that individual PTT devices were deployed multiple times on different animals)
deployment_location (the location of deployment: Spit Bay, Heard Island))
deployment_longitude (longitude of deployment location)
deployment_latitude (latitude of deployment location)
observation_date (the date of observation, in ISO8601 format yyyy-mm-ddTHH:MM:SSZ. This information is also separated into the year, month, day, etc components)
observation_date_year (the year of the observation date)
observation_date_month (the month of the observation date)
observation_date_day (the day of the observation date)
observation_date_hour (the hour of the observation date)
observation_date_minute (the minute of the observation date)
observation_date_second (the second of the observation date)
observation_date_time_zone (the time zone of the observation date)
latitude (the latitude of the observed position, in decimal degrees)
longitude (the longitude of the observed position, in decimal degrees)
location_class (the Argos location class of the observed position: one of (in increasing order of accuracy) B,A,0,1,2,3)
trip (the trip number of the animal)
at_sea (whether the observed position occurred at sea)
complete (whether the complete trip was recorded)

The fields in the campaign_41_supplementary.csv file are:

animal_id (the identifier of the individual animal)
behavioural_dive_group (1 = deep; 2 = shallow-active; 3 = shallow)
departure_date (date of departure of the animal on the trip)
departure_mass (mass of the animal on departure, in kg)
standard_length (standard length of the animal, in cm)
trip_duration (duration of the trip, in days)
dive_rate (dives per hour)
night_dive_rate (dives per hour)
mean_dive_duration (in seconds)
proportion_time_submerged
proportion_night_time_submerged
proportion_dives_in_bouts
mean_number_dives_per_bout
proportion_dives_at_night
vertical_depth_travelled_per_hr_of_night (in m)
proportion_vertical_depth_dived_at_night
vertical_depth_travelled_per_day (in m)
mean_dive_depth (in m)
mean_depth_deep_dives (in m)
mean_depth_shallow_dives (in m)
proportion_night_shallow_dive_duration
maximum_distance (in km)
heading (in degrees)

本数据集的元数据记录来自ASAC项目1251，如需了解该项目的公开详情，请参阅下方链接。

——项目公开摘要——
本研究旨在构建凯尔盖朗海台（Kerguelen Plateau）区域内南极海狗觅食密度的空间地理信息系统（Geographic Information System, GIS）模型，以此为海洋保护区（Marine Protected Area）的规划与管理提供快速评估手段，以识别具有高保护价值的海域。上述模型将基于赫德岛和麦克唐纳岛（Heard Island and McDonald Islands, HIMI）区域内的南极海狗觅食密度数据，以及水深测绘、海表温度和海洋水色（即初级生产力）的海洋学数据构建。

以下为参考文献论文的摘要内容：
本研究借助卫星遥测技术与时间深度记录仪，探究了赫德岛区域内泌乳期南极海狗（*Arctocephalus gazella*）的觅食活动时空分布特征。研究识别出两种主要潜水类型：平均深度为48.6米的「深潜」，以及平均深度为8.6米的「浅潜」。研究采用判别函数分析法，根据潜水深度与时长对潜水行为进行归类。对占总潜水次数80%以上的夜间潜水所构建的广义线性混合效应模型结果显示，深潜与浅潜的分布同时受到空间与时间因素的影响。深潜更多出现在凯尔盖朗海台的深水陆架区域，且主要集中在日落之后至日出之前的时段。与之相反，浅潜更多出现在凯尔盖朗海台东南边缘的斜坡水域，且主要集中在当地午夜前后的时段。研究认为，这两种截然不同的潜水类型分别对应着对冰鱼科（深潜）与灯笼鱼科（浅潜）鱼类的捕食行为，反映出这两类重要猎物的可获得性存在时空差异。此外，研究基于19项潜水与觅食行程参数的多维尺度分析，识别出3种不同的行为潜水类群，这些类群的空间分布特征以及深潜与浅潜的相对占比均存在差异。本研究首次提供了部分证据，表明海狗的潜水策略不仅受觅食地点的影响，同时也受觅食时间的影响。

campaign_41_tracks.csv 文件包含以下字段：
campaign_id（项目标识：aadc_campaign_41）
animal_id（单只个体标识）
scientific_name（物种学名：*Arctocephalus gazella*）
ptt_id（动物身上搭载的PTT设备标识。注：同一PTT设备曾被多次部署于不同个体上）
deployment_location（部署地点：赫德岛斯皮特湾）
deployment_longitude（部署地点经度）
deployment_latitude（部署地点纬度）
observation_date（观测日期，采用ISO8601格式：yyyy-mm-ddTHH:MM:SSZ。该信息同时拆分为年、月、日等独立字段）
observation_date_year（观测年份）
observation_date_month（观测月份）
observation_date_day（观测日期）
observation_date_hour（观测小时）
observation_date_minute（观测分钟）
observation_date_second（观测秒数）
observation_date_time_zone（观测日期所属时区）
latitude（观测位置纬度，采用十进制度格式）
longitude（观测位置经度，采用十进制度格式）
location_class（观测位置的Argos定位等级：按精度从低到高依次为B、A、0、1、2、3）
trip（个体的行程编号）
at_sea（观测位置是否处于海域内）
complete（是否完整记录了该行程）

campaign_41_supplementary.csv 文件包含以下字段：
animal_id（单只个体标识）
behavioural_dive_group（行为潜水类群：1=深潜类群；2=浅潜活跃类群；3=浅潜类群）
departure_date（个体出发进行行程的日期）
departure_mass（个体出发时的体重，单位：千克）
standard_length（个体的标准体长，单位：厘米）
trip_duration（行程时长，单位：天）
dive_rate（每小时潜水次数）
night_dive_rate（夜间每小时潜水次数）
mean_dive_duration（平均潜水时长，单位：秒）
proportion_time_submerged（总潜水时间占比）
proportion_night_time_submerged（夜间潜水时间占比）
proportion_dives_in_bouts（集群潜水次数占比）
mean_number_dives_per_bout（单次集群潜水的平均次数）
proportion_dives_at_night（夜间潜水次数占比）
vertical_depth_travelled_per_hr_of_night（夜间每小时垂直移动水深，单位：米）
proportion_vertical_depth_dived_at_night（夜间潜水垂直深度占比）
vertical_depth_travelled_per_day（每日垂直移动水深，单位：米）
mean_dive_depth（平均潜水深度，单位：米）
mean_depth_deep_dives（深潜平均深度，单位：米）
mean_depth_shallow_dives（浅潜平均深度，单位：米）
proportion_night_shallow_dive_duration（夜间浅潜时长占比）
maximum_distance（最大移动距离，单位：千米）
heading（行进方向，单位：度）