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EARTH SCIENCE > BIOSPHERE > ECOLOGICAL DYNAMICS > SPECIES/POPULATION INTERACTIONS > POPULATION DYNAMICS

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  • A GPS survey of seabirds on Heard Island during the Australian Antarctic Program's 2000/01 expedition. This layer is stored as two datasets (polygon and point) in the Geographical Information System (GIS). Polygon data represent flying bird and penguin colony extents. Point data represent nest locations and the location of the observation point for flying birds and penguins.

  • This dataset comprises oblique aerial photographs of multiple Adelie penguin breeding sites in East Antarctica. The photographs were taken using hand-held digital cameras from fixed-wing aircraft and helicopters used by the Australian Antarctic Program. The aircraft flew at or above the minimum wildlife approach altitude of 750 m with a horizontal offset distance from the site of approximately 500-600m. The date and exact location of the aircraft when each photo was taken is embedded in the EXIF data of each photo. All photographs that were taken are included despite varying image quality due to environmental conditions, camera type and altitude. Generally an attempt was made to photograph the entire breeding site (usually an island, occasionally an outcrop of continental rock) with a series of zoomed, overlapping photos. Sometimes this was not possible when the site was large, and in these cases the overlapping photos covered the locations where colonies were known to exist from previous survey work. In some cases a site was over-flown at an altitude of 1200m so that a single photo of the entire site could be taken. These photos are useful in piecing together the detailed photos. The database of potential Adelie penguin breeding habitat in Southwell et al. (2016a) was used to associate photos to a particular breeding site and structure how the photos are stored. The breeding site database has a unique identifying code of every site of potential breeding habitat in East Antarctica, and the sites are aggregated into sub-groups and then groups. The file structure in which the photos are stored has a combination of ‘group’ and ‘split-year breeding season’ at the top level (eg VES 2015-16 contains all photos in group VES (Vestfold Hills and islands) taken in the 2015-16 breeding season). Within each group-year folder are sub-folders for each breeding site where photos were taken (eg IS_72276 is Gardner Island in the VES group). If an overview photo was taken there are separate sub-folders for overview and detailed photos in the site sub-folder. These data also superseded an earlier dataset of 2009-2016 data - https://data.aad.gov.au/metadata/records/AAS_4088_Adelie_oblique_photos Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

  • This dataset is a document describing the Chaetognaths of the Southern Ocean. The synonymy, diagnostic characters, geographical and bathymetric distribution of each species is given together with an illustration of body, head and a seminal vesicle, and a distribution map. The document is available for download as a pdf from the provided URL.

  • Coccolithophore fluxes were investigated over a one-year period (2001-02) at the southern Antarctic Zone in the Australian Sector of the Southern Ocean at the site of the Southern Ocean Iron Release Experiment (SOIREE) near 61°S, 140°E. Two vertically moored sediment traps were deployed at 2000 and 3700 m below sea-level during a period of 10 months. In these data sets we present the results on the temporal and vertical variability of total coccolith flux, species composition and seasonal changes in coccolith weights of E. huxleyi populations estimated using circularly polarised micrographs analysed with C-Calcita software. A description of the field experiment, diatom and biogeochemical fluxes can be found in Rigual-Hernández et al. (2015), while a detailed description of sample processing and counting of coccolithophores can be found in Rigual-Hernández et al. (2018). Moreover, an explanation of the estimation of Emiliania huxleyi coccoliths using C-Calcita software can be also found in Rigual-Hernandez et al. (2018). Coccolithophore assemblages captured by the traps were nearly monospecific for Emiliania huxleyi morphotype B/C. Coccolith fluxes showed strong seasonal cycle at both sediment trap depths. The maximum coccolith export occurred during summer and was divided into two peaks in early January (2.2 x 109 coccoliths m-2 d-1 at 2000 m) and in mid-February (9.8 x 108 coccoliths m-2 d-1). Coccolith flux was very low in winter (down to ~7 x 107 coccoliths m-2 d-1). Coccolith fluxes in the deeper trap (3700 m) followed a similar pattern to that in the 2000 m trap with a delay of about one sampling interval. Coccoliths intercepted by the traps exhibited a weight and length reduction during summer. The annual coccolith weight at both sediment traps was 2.11 plus or minus 0.96 and 2.13 plus or minus 0.91 pg at 2000 m and 3700 m, respectively. Our coccolith mass estimation was consistent with previous reports for morphotype B/C in other regions of the Southern Ocean. Data available: two excel files containing sampling dates and depths, raw counts, relative abundance and fluxes (coccoliths m-2 d-1) of the coccolithophore species, and morphometric measurements of Emiliania huxleyi coccoliths made with C-Calcita software. Each file contains four spreadsheets: raw coccolith counts, relative abundance of coccolithophore species and coccolith flux of each coccolithophore species identified and E. huxleyi morphometrics. Detailed information of the column headings is provided below. Cup – Cup (=sample) number Depth – vertical location of the sediment trap in meters below the surface Mid-point date - Mid date of the sampling interval Length (days) – number of days the cup was open

  • 1. The Excel spreadsheet titled "1_Cape Petrel Population adjusted Estimates_Table1.xlsx is population survey count data and estimates of Cape petrels in the Vestfold islands, East Antarctica in 1974 and 2017. Numbers present the number of occupied nests in each year. Adjusted data as per ICESCAPE modelling and provides a value based on attendance of Cape petrels relative to phenology, values in brackets are the lower and upper confidence intervals based on 95% confidence. No data is where there was no survey data available; however a 0 indicates the island was searched, however no breeding birds recorded at that site. Four surveys of Cape petrel breeding populations have been conducted in the Vestfold Islands: 1972-73 (Johnstone et al 1973), 1974-75 (AAD unpublished data), 2016-17 (Louise Emmerson and Anna Lashko) and 2017-18 austral summers (Kimberley Kliska and Marcus Salton). Here we refer to breeding seasons as the year eggs were laid, which was also when surveys were conducted. For example, 1972-73 breeding season spans from October 1972 until April 1973 and is referred to as 1972; 1974/75 is referred to as 1974 and 2017/18 as 2017. In 1972, numbers of occupied nests and distribution were assessed from ground surveys across the Vestfold Islands region and Cape petrels were found only in the southern half of the Vestfold Islands. In 1974, all accessible islands in this southern region were again surveyed from the ground or sea ice for Cape petrels from Bluff Island south to the Sørsdal Glacier. In addition, the ‘Northern Islands’ (Figure 1) were opportunistically searched during seal surveys conducted from 1-8th November 1974, and no sign of breeding Cape petrels were recorded (Williams, pers. comm. 2020). The 2016 survey focussed on identifying islands with cape petrels present in the south from ground-based activities, and in the north from aerial surveys. The 2017 survey focused search effort on all the islands where breeding Cape petrels were observed in 1972 and 1974. Similar to the 1974 survey, the Northern Islands were opportunistically searched for Cape petrels during seal surveys between the 5-13th December 2017, and no Cape petrels were observed. To our knowledge, no Cape petrels have been observed in the Northern Islands. We are therefore confident that this study encompasses the entire Vestfold Islands population. To assess the status and temporal change in population numbers of Cape petrels in the Vestfold Islands, datasets from the three breeding seasons were analysed, with two complete datasets, one a combination of both the 1972 and 1974 surveys and one from the 2017 survey were used in the final analysis. Three islands surveyed in the 1972 survey were not surveyed in 1974, therefore to complete the dataset for the 1974, the counts from these three islands in 1972 (Magnetic, Turner and Gardner Islands) were used to fill data gaps in 1974. The complete dataset is referred to as the 1974 dataset. Historical count data from 1972 and 1974 seasons were obtained from Johnstone et al 1973 and the Australian Antarctic Division Davis Biology species log 1974, respectively. In the 1972 survey, breeding pairs were estimated at various locations by island name and symbol shape on hand drawn maps. These symbols indicated which side of an island Cape petrels were located. In the 1974 survey breeding pairs of Cape petrels were recorded, as counted from the sea ice or by ground searching on the 17th of November and the 17th of December 1974. Locations of breeding Cape petrels were recorded with cross marks on hand drawn maps, indicating which gully or slope on an island Cape petrels were located. To ensure consistency of survey dates, both the Davis Station log book 1974 and the personal journal of Richard Williams (the biologist who undertook the survey work in 1974) were cross checked for survey dates. In the 2017 season, the survey was conducted over three days (18th, 20th and 30th of November) at all known Cape petrel breeding colonies. At each breeding colony a combination of ground searches and/or binocular counts were conducted from a vantage point on the sea ice tens of meters perpendicular away from Cape petrel breeding areas with the aim of counting all occupied nests. Occupied nests were classified as Confirmed if a bird was present at the nest and Unconfirmed if a nest was suspected but no bird observed (i.e. bowls of small pebbles and/or large amounts of guano on rocks were indicative of nests). Counts of confirmed nests were used to represent the number of occupied nests in 2017, and were considered consistent with breeding pair estimates in historic surveys. Birds observed on ledges without guano were considered loafing rather than breeding and not included in counts. The locations of breeding colonies were recorded using a combination of geographical positioning system (GPS) locations, hand-drawn maps and photographs of breeding colonies from the vantage point where counts were conducted. To compare changes between surveys, the Vestfold Island region was divided into two sections: Northern Islands and Southern Islands. The Southern Islands were further classified into three areas labelled A, B, and C. Area A is the northern part of the Southern Islands and includes Bluff, Turner, Magnetic and Gardner Islands and the Davis Station, and has the most persistent fast ice. Area B includes Hawker and Mule Islands and is further south, with intermediate fast ice duration, and Area C includes Zolotov and Kazak Islands and is furthest south, just north of the Sørsdal Glacier, and has the earliest loss of fast ice (Figure 1).To account for potential uncertainty in the population counts, we assumed the counts were within ±10% (with 95 % confidence) of the true number present. We refer to this as ‘count repeatability’. 2. Attendance data titled "2_Attendance_CapePetrels_BluffIsland_2019-2020.csv." The attendance data is derived from images taken with a remotely deployed camera at the Bluff Island Cape petrel colony near Davis station, East Antarctica. This phenology of cape petrel at this colony was used to adjust historical and contemporary population estimates of the Cape Petrel population. The .csv file includes latitude and longitude, season, calendar time and date, and an occupied nest count from the 6th of November 2019 until the 8th of March 2020. The camera data were counted by Kimberley Kliska in June 2020 as part of a project investigating the phenology of Cape petrels in this region. 3. The dataset in folders titled "1970s polygons" and "2017 polygons revised" contains boundaries of Cape petrel nesting areas at numerous breeding sites on islands off the Vestfold Hills, Antarctica, for the purpose of assessing change in the bird’s distribution between the early 1970s and 2017 (Kliska et al. 2021 manuscript in review). Nest areas were identified in the early 1970s during three surveys over three years 1972, 73 and 74, and in 2017 during one survey that year. Details of the surveys in 1970s were presented in the ANARE SCIENTIFIC REPORTS publication N. 123 ‘The Biology of the Vestfold Hills, Antarctica’ 1972-73 summer, and in the Davis Biology Species Log 1974 (included 1973-74 summer and 1974-75 summer) (the latter by Richard Williams). Details of the survey in 2017 were presented in the Seabirds Research end-of-season field report Davis 2017-18 summer (by Kim Kliska and Marcus Salton). Polygons created from the 2017 survey are published with the AADC (Emmerson and Southwell 2020). In both periods the islands were surveyed either by ground searching an area on foot or by visualising the birds from a distance with or without binoculars, and then transcribing the area with nests onto hand drawn maps. These hand drawn maps were transcribed on to spatially projected electronic maps by Marcus Salton to represent the maximal perimeter of the cape petrel nest areas. In the 1970’s surveys, the depicted nesting areas represented locations where birds were observed sitting on or next to nests (or extensive guano deposits that were indicative of a nest). Birds that were on rocks and not associated with a nest or extensive guano deposits were considered non-breeding, and areas with extensive guano deposits without birds considered inactive nests, which were both omitted from the nesting area. The polygons that had already been created from the 2017 survey (Emmerson and Southwell 2020) were modified to match this representation of nesting area, by excluding areas within inactive nests (based on recollections of Kim Kliska and Marcus Salton). Polygons were created using R computing software version 4.0.2 (2020-06-22). The spatially projected electronic maps were derived from two shapefiles from the AADC: a coastline file (‘all_coast_poly_2003.shp’ DOI) and a contour file (‘vestfold_contours.shp’ DOI). These shapefiles were projected using Azimuthal equidistant, with the centre of the study area at latitude = -68.5785 and longitude = 77.8709 for visualisation purposes. Polygons are grouped by island. Not all islands have formal names. Therefore the number system created by Southwell (2016 a, b) for a project on Adelie penguins was adopted.

  • This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION All known observations of seabird strikes are recorded upon observation at Australian Antarctic Stations and on ships travelling in the Southern Ocean. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: PRESSURE RATIONALE FOR INDICATOR SELECTION Human presence in the Antarctic has led to the creation of many stations located around the continent. In many cases, these stations are sited close to seabird colonies. Birds have struck station buildings, radio masts, etc. Further, seabird strikes are reported from resupply and research vessels. In recent decades, there have been observations made of bird strikes, particularly colliding with station infrastructure, remote installations and supporting infrastructure and ship-based transport to the continent. Whilst the data are not considered to be comprehensive or highly rigorous, it is envisaged that recording of bird strikes may facilitate useful analysis in the future. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial scale: Southern Ocean: 40S to the Antarctic continent, Mawson, Davis, Casey, Macquarie Island, Heard Island, field camps, and summer expeditions. Frequency: Annual. Measurement technique: Observation of bird strikes at Australian Antarctic Stations and at sea. RESEARCH ISSUES The accuracy of the data are likely to be limited as it depends upon the detection of bird strikes by actual observation of the strike as it occurs, or the discovery of bird carcasses near the structure with which it collided. LINKS TO OTHER INDICATORS SOE Indicator 29 - Breeding population of the Southern Giant Petrel at Heard Island, the McDonald Islands and within the AAT SOE Indicator 37 - Species and numbers of species killed, taken or interfered with or disturbed in the Antarctic and the sub-Antarctic for the purpose of scientific research SOE Indicator 46 - Annual tourist ship visits and tourist numbers SOE Indicator 48 - Station and ship person days SOE Indicator 76 - Monthly fuel usage of ships travelling to Australian Antarctic Stations

  • INDICATOR DEFINITION Count of all adult females, fully weaned pups and dead pups hauled out on, or close to, the day of maximum cow numbers, set for October 15. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Elephant seals from Macquarie Island are long distance foragers who can utilise the Southern Ocean both west as far as Heard Island and east as far as the Ross Sea. Thus their populations reflect foraging conditions across a vast area. The slow decline in their numbers (-2.3% annually from 1988-1993) suggests that their ocean foraging has been more difficult in recent decades. Furthermore, interactions with humans are negligible due to the absence of significant overlap in their diet with commercial fisheries. This suggests that changes in 'natural' ocean conditions may have altered aspects of prey availability. It is clear that seal numbers are changing in response to ocean conditions but at the moment these conditions cannot be specified. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial Scale: Five beaches on Macquarie Island (lat54 degrees 37' 59.9' S, long 158 degrees 52' 59.9' E): North Head to Aurora Point; Aurora Point to Caroline Cove; Garden Cove to Sandy Bay; Sandy Bay to Waterfall Bay; Waterfall Bay to Hurd Point. Frequency: Annual census on 15th October Measurement Technique: Monitoring the Southern Elephant Seal population on Macquarie island requires a one day whole island adult female census on October 15 and a daily count of cow numbers, fully weaned pups and dead pups on the west and east isthmus beaches throughout October. Daily cow counts during October, along the isthmus beaches close to the Station, provide data to identify exactly the day of maximum numbers. The isthmus counts are recorded under the long-established (since 1950) harem names. Daily counts allow adjustment to the census totals if the day of maximum numbers of cows ashore happens to fall on either side of October 15. Personnel need to be dispersed around the island by October 15 so that all beaches are counted for seals on that day. This has been achieved successfully for the last 15 years. On the day of maximum haul out (around 15th October) the only Elephant seals present are cows, their young pups and adult males. The three classes can be readily distinguished and counted accurately. Lactating pups are not counted, their numbers are provided by the cow count on a 1:1 proportion. The combined count of cows, fully weaned pups and dead pups provides an index of pup production. The count of any group is made until there is agreement between counts to better than +/- 5%. Thus there is always a double count as a minimum; the number of counts can reach double figures when a large group is enumerated. The largest single group on Macquarie Island is that at West Razorback with greater than 1,000 cows; Multiple counts are always required there. RESEARCH ISSUES Much research has been done already to acquire demographic data so that population models can be produced. Thus there will be predicted population sizes for elephant seals on Macquarie Island in 2002 onwards and the annual censuses will allow these predictions to be tested against the actual numbers. The censuses are also a check on the population status of this endangered species. LINKS TO OTHER INDICATORS

  • We estimate population size in terms of the number of occupied nests for the Adélie penguin metapopulation in western Mac. Robertson Land, East Antarctica in 2009/10 and 2019/20. We also assessed demographic data from a single breeding site in the central part of this area (Béchervaise Island: 67°35'S, 62°49'E) including reproductive success, resight data, and fledgling mass from 1991/92 to 2019/20. We collated environmental covariates of potential drivers in this area over the same time period from sources described below. These are presented in the file “Time series demography and environmental covariates.xls”. Environmental covariates: Sea-ice concentration: Summer sea-ice concentration (SIC) was obtained for the area bounded by longitudes 60 - 65°E, to the south by the Antarctic coastline and the north by latitude 66.75°S. This approximately 250 km stretch of coastline incorporates the location of all Adélie penguin breeding sites across the metapopulation. The area defines the most northerly limit of fast-ice during chick rearing and encompasses the longitudinal range of the birds’ summer foraging activities. The sea-ice contained within this ‘near-shore’ region is predominantly composed of fast-ice (ice that is attached to land but covers seawater). Summer SIC was calculated as an average over the three-week period 25th December to 15th January when adults are guarding chicks for each breeding season. Winter SIC was determined in the following three areas of the penguins’ winter migratory route as defined previously. Each area was defined between specific longitudes and from 50°S south to the Antarctic coastline. The sea-ice contained within this area is composed of fast-ice near the coastline and pack-ice (all sea-ice that is not fast-ice) beyond the fast-ice edge. Two sectors defined the outward journey as they travelled westward towards their winter foraging grounds (50 - 65°E during March, and 30 - 50°E during April), a winter area (15 - 30°E during May-Jul) was considered as the sea ice became more extensive with both 15-100% SIC and 15-80% SIC which is considered more in line with suitable winter foraging ice conditions. The final area was associated with their eastwards journey towards the colony (30 - 50°E during Aug-Sep). For each area and time period, an average SIC was determined for each year in each of these areas. SIC values reflect the total area (km2) covered in sea-ice between either 15-100% or 15-80% SIC in each year and time period using 25x25km pixels. Sea-ice data were obtained from the National Snow and Ice Data Center (NSIDC) (Cavalieri et al. 1996) using Raadtools (Sumner 2017). Broad-scale climatic indices and local weather conditions: We determined the weather conditions during periods reflecting the end of the austral summer when the penguins were leaving their colonies (Feb-Mar) and the inter-breeding winter period (Apr-Sep). The Southern Oscillation Index (SOI) and the Southern Annular Mode (SAM) were included as broad indicators of climatic conditions, and local weather conditions included air and windchill temperatures. SOI was obtained from the Australian Bureau of Meteorology (www.bom.gov.au) and SAM from the NOAA Climate Prediction Centre (http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao_index.html). Mawson Station local weather: Local weather data recorded at Mawson Station were obtained from the Australian Bureau of Meteorology. We considered two covariates: windchill and air temperatures both reported in °C. Windchill temperatures were determined from the ambient air temperature, wind speed and the relative humidity: AT= Ta +0.33e-0.7ws-4.0, where Ta is the dry bulb temperature (°C), e is the water vapour pressure (hPa), and ws is the windspeed (ms-1) at 10 m elevation. Water vapour pressure was determined from: (see the actual equation in the download file - "Emmerson_AADC Metadata Records_GCB_2022.docx" - unable to be reproduced here), where rh is the relative humidity (%). This formula follows the Australian Bureau of Meteorology calculation (www.bom.gov.au/info/thermal_stress/). Seabird population parameters: Pre-fledging mass "adjusted.fledge.mass.5_Feb": We determined pre-fledging mass (g) of chicks on the 5th February by either measuring their mass on that date, or by standardising to that date from measurements made between the 3rd and 14th February. Total chick productivity "tot.chick.prod.past.5.yrs": Cumulative five-year total chick productivity (total chicks) was calculated for each year using total counts across Béchervaise Island from the preceding five years. This represents the cumulative pool of pre-breeders on the basis that Adélie penguins typically recruit into the breeding population between the ages of one and five years. Breeding success "bs.3.yr.ave": at Béchervaise Island was measured as the number of chicks crèched (end-January) in relation to the number of nests occupied at the start of incubation (late November and beginning of December). Units of measurement are chicks per occupied nest. Nest and chick counts were obtained annually from on-ground island-wide surveys. Because reproductive performance fluctuates dramatically across years, we calculated three-year rolling averages centred on the year of interest. Resight data: Age of first return to the colony or recruitment into the breeding population “Age first.nesting.all.6.years” were based on resights of birds in their natal colony. Marked birds were resighted via colony-wide detection from a tag reader when they were on nests. Files for each year contain data from resighting with hand-held tag readers across Béchervaise Island including date of resight and the tag number with each file named as “2003_04 resights.xls” for the resights in 2003/04 split-season for example. For resight data outside the years available in this data repository, please contact Data Custodians. Population growth rates: Circum-Antarctic population growth rates: To allow a circum-Antarctic comparison of this populations growth rate with other sites or regions, we performed a literature review of published data or growth rates for estimating a consistent metric of growth rate. Data from this search are included in this dataset along with estimates of population growth rate in this study in file “Circum-Antarctic estimates of population growth rates for Adelie penguins Figure 2.pdf”. Occupied nest counts Mac. Robertson Land: Adult counts were adjusted for phenology-related variable attendance and potential methodology bias to a standard metric (the number of occupied nests at the beginning of the incubation period). The adjustment process is described in detail in Southwell et al. (2013) and propagates the uncertainties from accounting for these biases through to the final estimate of occupied nests. Data include 1000 bootstrap estimates of occupied nests from this procedure for the Mac. Robertson Land area to standardise raw counts to the metric of occupied nests labelled as “O.N.bootstrap.estimates.2009_10” for 2009/10 and 2019/20 which we summarised with the median and 95 percentile limits. Please see manuscript for further details on the standardisation process. Data presented in file “W Mac. Robertson Land Adelie penguin population estimates.xls”. Any data use from this repository in any publication, report or presentation, should include the following acknowledgement in each data file based on the following “Data from Béchervaise Island or Mac. Robertson Land were derived from Australian Antarctic Science projects 2205, 2552, 4088, 4086 and 4518. All procedures were approved through Australian Antarctic Division animal ethics and ATEP approvals.” Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

  • This dataset comprises counts of Adelie penguins attending breeding sites from images obtained with 20 remotely operating cameras across East Antarctica. Counts were made of adults, occupied nests and chicks every few days throughout the breeding season from October through to February. Locations of cameras are given in an associated dataset (Photographic images of seabird nesting sites in the Antarctic, collected by remote camera) which also provides the images obtained from the cameras. Please refer to the Seabird Conservation Team Data Sharing Policy for use, acknowledgement and availability of data prior to downloading data.

  • This integrated stock assessment for the Patagonian toothfish (Dissostichus eleginoides) fishery at the Heard Island and the McDonald Islands in CCAMLR Division 58.5.2, with data until end of July 2015, is based on the best available estimates of model parameters, the use of abundance estimates from a random stratified trawl survey (RSTS), longline tag-release data from 2012-2014 and longline tag-recapture data from 2013-2015, and auxiliary commercial composition data to aid with the estimation of year class strength and selectivity functions of the trawl, longline and trap sub-fisheries.All model runs were conducted with CASAL version 2.30-2012-03-21 (Bull et al. 2012). The assessment model leads to an MCMC estimate of the virgin spawning stock biomass B0 = 87 077 tonnes (95% CI: 78 500-97 547 tonnes). Estimated SSB status in 2015 was 0.64 (95% CI: 0.59-0.69). Using this model, a catch limit of 3405 tonnes satisfies the CCAMLR decision rules. Similarly to the 2014 assessment, the projected stock remains above the target level for the entire projection period.