Winter foraging success of Southern Ocean predators in relation to stochastic variation in sea-ice extent and winter water formation
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Metadata record for data from ASAC Project 2794 See the link below for public details on this project. Public: This study will use innovative technology to measure the winter spatial foraging patterns and net energy gain of adult female elephant seals (and potentially Weddell seals), while simultaneously providing high-resolution data on the physical nature of the water column in which the seals live. By combining biological and physical data with satellite derived sea-ice information, this study will improve our understanding of predator foraging success (and therefore mechanisms which regulate population trajectories) and provide physical oceanographers with fundamental data on the importance mechanisms that determine the winter ice and bottom water formation that under-pin the Antarctic marine ecosystem. Project objectives: The extent and nature of Antarctic winter sea ice is thought to have profound impacts on biological productivity, the recruitment of Antarctic krill, and the flow-on effects through the Antarctic marine food web. 1. Winter sea-ice formation is also hypothesised to play an important, yet highly-variable role in ocean circulation patterns through the production of cold, dense winter bottom water. 2. The mechanisms determining the inter-annual variation in winter ice formation are poorly understood, as are the complex feedback processes involved, but they are nonetheless recognised as being vulnerable to human-induced climate change. 3. Given the dynamically-linked nature of winter-ice and biological productivity, long-term climatic changes will have broad scale influences on Antarctic biota. This study will use innovative technological developments to quantify the response of one of the major Antarctic marine predators, the southern elephant seal (Mirounga leonina), to inter-annual variation in winter ice conditions. We will measure the winter spatial foraging patterns and net energy gain of adult female elephant seals while simultaneously providing high-resolution data on the physical nature of the water column in which the seals are living. The combination of these biological and physical data with satellite-derived sea-ice information will relate variation in the winter-ice to broad scale biological production through the foraging success (maternal investment and therefore demographic performance) of a top Antarctic marine predator, as well as providing physical oceanographers with fundamental data on the important mechanisms that determine the winter ice and bottom water formation that under-pin the Antarctic marine ecosystem. The specific objectives are to: Measure the foraging performance of the seals in terms of spatially-specific net energy gain while at sea, in relation to intra- and inter-annual variation in sea-ice and oceanic processes. Use newly-developed (and tested) animal-borne satellite-linked Conductivity-Temperature-Depth Satellite Relay Data Loggers (CTD-SRDLs) to provide oceanographic quality data on local physical characteristics (temperature and salinity). Record fine-scale foraging parameters (dive depth, duration, swimming speed) using "Dead-Reckoning" Data Loggers (DRDLs) and feeding events using Stomach Temperature Sensors (STSs). Integrate these data collected in years and regions of different winter ice extent and conditions. Assess diet during the winter months using stable isotope and fatty acid signature analysis. Combine the biological and physical information to refine current models of predator performance based on annual climatic features. These models will be used to examine a range of climate-change scenarios, initially for elephant seals but with a view to broadening the species application at a later stage. Taken from the 2008-2009 Progress Report: Progress against objectives: Due to logistic constraints, no satellite telemetry was conducted at Casey or Macquarie Island this year, but preliminary surveys of the region were conducted for both elephant and Weddell
Distribution of foraging effort of Antarctic fur seals in relation to oceanographic features around Heard and Kerguelen Islands
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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
Population abundance, trend, structure and distribution of the endangered Antarctic blue whale
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This is a parent record for data collected from AAS project 4102. Project 4102 also follows on from ASAC project 2683, "Passive acoustic monitoring of antarctic marine mammals" (see the related metadata record at the provided URL). Public Summary: Half a century ago the Antarctic blue whale was perilously close to extinction. Over 350,000 were killed before the remaining few were fully protected. A decade ago this elusive and poorly understood species was estimated to be less than 5% of its pre-whaling abundance. This multi-national, circumpolar project will develop and apply powerful new techniques to survey these rare whales and gain an insight into their recovery and ecology. The project is the flagship of the Southern Ocean Research Partnership - an International Whaling Commission endorsed collaborative program.
Antarctic Fur Seal Populations on Heard Island Summer 1987-1988
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Abstract from ANARE Research Notes 72 The Antarctic fur seal Arctocephalus gazella has increased in numbers at Heard Island since the Australian National Antarctic Research Expeditions (ANARE) station was established in 1947. Increases have also been recorded at other breeding sites in the South Atlantic and South Indian Oceans this century, particularly at South Georgia. In the 1987-88 summer, fur seals at Heard Island were counted in several age and sex categories. The aims of the project were to determine the location of pupping sites, the extent of the pupping season and the size of the population, and to record the changes in numbers of animals ashore during the summer. Maps of the colonies and main haul-out areas, together with descriptions of census areas and tabulations of counts, provide a basis for future comparison. This dataset contains the results from surveys of Antarctic Fur Seals (Arctocephalus gazella) on Heard Island during the summer of 1987-1988. As well as habitat descriptions, age, sex, count of adults and pups were determined. The three major aims of the study include: to determine accurately the location of pupping sites; to determine the extent of the pupping season, the median date of birth and the number of pups born; and to census fur seals on as much of the island as possible in order to determine the number of animals ashore and to document changes in numbers during the summer. The results are listed in the document, which includes detailed tabulations of counts made at colonies and major haul-out sites on Macquarie Island during summer 1987-88, and descriptions and maps of these locations. Tagging, mainly of pups, was also undertaken, and a total of 234 pups, 8 under-yearlings, 9 yearlings, 2 juveniles and 1 sub-adult male were tagged. Counts at 3-day intervals (pups) were made between 25 November and 19 December 1987, and major censuses were made between 19 December 1987 and 25 February 1988. The fields in this dataset are: Locality Age Class Date Colony Bulls Cows Pups
Acute bottlenecks to the survival of juvenile Pygoscelis penguins
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This data set contains a zipped file with 8 individual .csv files used to support the analysis of survival bottlenecks presented by Hinke et al.(2020), "Acute bottlenecks to the survival of juvenile Pygoscelis penguins occur immediately after fledging". Data include geographical position estimates from satellite telemetry studies on Adélie (Pygoscelis adeliae), chinstrap (P. antarctica), and gentoo (P. papua) penguins tracked from the Antarctic peninsula region, carcass counts from ship and beach surveys in the study region, fledgling weights, and battery voltage data from telemetry tags. Multiple datasets are provided. Telemetry data is raw ARGOS data collected from Sirtrak Kiwisat K2G-72A transmitters on Adelie, gentoo, and chinstrap fledlging penguins. Summarized data on cumulative losses of tags from adult birds dervie from Wildlife Computers Spot-275 transmitters. Historical raw data collected by field researchers include fledgling weights and counts of penguin carcass observed at sea and on beaches. Fledgling weights are were collected with spring scales immediatley prior to first departure of fledgling penguins from their natal colony (Adelie and chinstrap) or at a standard age of 85-days after hatch (gentoo). At-sea carcass observations were collected during standard seabird surveys while underway during daylight hours. Beach-cast carcasses of fledgling chinstraps were counted one week after the fledging period at Cape Shirreff, Livingston Island. Recruitment data are based from mark-recapture data and represent proportional returns of individuals from marked cohorts, as updated from a prior report (doi: 10.1007/s00442-007-0781-4)
Winter Foraging Locations Of Southern Ocean Predators - sub-Antarctic islands
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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.
Comparative Diving Ecology Across Southern Ocean Marine Predators - Seals and Penguins
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This study was carried out by Giulia Roncon as part of her PhD at IMAS. The study employed both archival and contemporary diving data, collected by six species of marine predators (three penguins and three seal species) from the Eastern Antarctic sector of the Southern Ocean, to clarify key questions, such as (i) are there differences and/or commonalities regarding the diving physiology and ecology of marine predators, and (ii) what are the main determinants and constrains that characterise the underwater behaviour of air-breathing vertebrates. This dataset is a compilation of data of several different studies carried out by different research teams in various locations and at various times. All TDRs were archival loggers that had to be retrieved to obtain the data. Thus, the animals had to be captured twice (deployment and retrieval). Details about the types of tags are listed in the dataset. Species used in the study were: Adelie Penguins Emperor Penguins King Penguins Fur Seals Southern Elephant Seals Weddell Seals
Weddell Seal underwater calling rates during the winter and spring near Mawson Station, Antarctica
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During the winter and spring of 2002, underwater calling rates were measured near mid-day on an opportunistic basis at 7 breeding sites and, at two breeding sites, over 24 hour periods once a month. The data were analysed with respect to reproductive season (early ice formation, prebreeding, pupping and mating) and if the recordings were made when it was dark or twilight/light. Taken from the abstract of the paper referenced below: Underwater vocalisation monitoring and surveys, both on ice and underwater, were used to determine if Weddell seals (Leptonychotes weddellii) near Mawson Station, Antarctica, remain under the fast ice during winter within close range of breeding sites. Daytime and nighttime underwater calling rates were examined at seven breeding sites during austral winter and spring to identify seasonal and diel patterns. Seals rarely hauled out at any of the sites during winter, although all cohorts (adult males, females, and juveniles) were observed underwater and surfacing at breathing holes throughout winter (June-September) and spring (October-December). Seal vocalisations were recorded during each sampling session throughout the study (n=102 daytime at seven sites collectively, and n=5 24-h samples at each of two sites). Mean daytime calling rate was low in mid-winter (July) (mean = 18.9 plus or minus 7.1 calls per minute) but increased monthly, reaching a peak during the breeding season (November) (mean = 62.6 plus or minus 15.7 calls per minute). Mean nighttime calling rate was high throughout the winter and early spring (July-October) with mean nocturnal calling rate in July (mean = 61.8 plus or minus 35.1 calls per minute) nearly equal to mean daytime calling rate in November (during 24-h daylight). Reduced vocal behaviour during winter daylight periods may result from animals utilising the limited daylight hours for nonvocal activities, possibly feeding. The following study sites were among those used in this project (provided by Phil Rouget): Forbes site (identified as Site 6 in the paper) is located at Forbes Glacier (approx. 0.5 km to the west of the glacier tongue and approximately 200 meters offshore of the mainland). (67 degrees 35.256 minutes S, 62 degrees 16.756 minutes E) Kista site is located in the middle of Kista Strait (site 7 in the Marine Mammal Science paper). (67 degrees, minutes 33.840 S, 62 degrees 47.402, minutes E) SPA site was our site located just west of the western boundary of the SPA which itself is located west of Mawson and east of Forbes Glacier. (Site 2 in Marine Mammal Science paper). (67 degrees 35.179 S, 62 degrees 25.425 minutes E) McDonald Islands (or Rocks) was the site located North/NorthWest of Kista Strait, as it is named so on the Framens Mtn. Nautical Chart. From memory, it was approximately 12 km north/north west of Mawson Station. (This was site 5 in the Marine Mammal Science paper). (67 degrees 29.414 minutes S, 62 degrees 41.011 minutes E) Stewart Rocks (also named Sewart Rocks on an alternative map) is located due north of Mawson Station, also by about 12 km. (East of McDonald site, and North East of Kista). This was site 4 in the Marine Mammal Science paper. (67 degrees 29.933 minutes S, 62 degrees 51.765 minutes E) Anderson Rocks is an extensive group of rocky islets west of Auster Island (approximately 6-7 km offshore). This was site 3 in the Marine Mammal Science paper. (67 degrees 26.445 minutes S, 63 degrees 25.414 minutes E) SEAL MO was located just north of Macey Hut by about 2 km. This was site 1 in the Marine Mammal Science paper. (67 degrees 23.399 minutes S, 63 degrees 47.977 minutes E) Aside from SEAL MO and SPA, the names from all these sites are indicated in the Framnes Mountain Chart. An image showing the locations of the fields sites is also part of the download file. The fields in this dataset are: Site Period Day Calling rate photoperiod Sun time