Water temperatures were recorded by Tidbit temperature loggers attached to experimental mesocosms suspended below the sea ice at four sites around Casey in summer 2003/04. Data are temperature in degrees Celsius automatically logged every 5 minutes between the 01/12/2003 and 31/12/2003 at Brown Bay inner (S66 16.811 E110 32.475) and McGrady Cove (S66 16.556 E110 34.392), and between 02/12/2003 and 01/01/2004 at Brown Bay outer (S66 16.811 E110 32.526) and O'Brien Bay (S66 18.730 E110 30.810). Three loggers were deployed at each site; loggers A and B - one attached to each of two mesocosms (perforated 20 litre food buckets) and another - logger I - attached to plastic tubing approximately 1 metre above the mesocosms. Only two data loggers (A and B) were deployed at Mcgrady Cove. Mesocosms were suspended two to three metres below the bottom edge of the sea ice through a 1 metre diameter hole and were periodically raised to the surface for short periods (~1 hour). This experiment was part of the short-term biomonitoring program for the Thala Valley Tip Clean-up at Casey during summer 2003/04. These data were collected as part of ASAC project 2201 (ASAC_2201 - Natural variability and human induced change in Antarctic nearshore marine benthic communities). See also other metadata records by Glenn Johnstone for related information. The fields in this dataset are: Date Time Temperature Location

Sea ice covers up to 20 million km2 of the Southern Ocean. When present it supports a vigorous ecosystem that provides energy and food for all other marine organisms. Using the latest micro sensor technology, we are examining the factors that effect the productivity of this vital link in the Antarctic marine food web. New data were added to this metadata record in January 2011. These data included FRRF data collected on the CEAMARC, CASO, SIPEX and SAZ-SENSE voyages. A word document in the download file provides details about these datasets, plus those collected on Voyage 1 2009-2010, and voyage 2 2008-2009. The download file also contains a folder labelled "Older data". This data is described below: An explanation of the excel spreadsheet in the download file is as follows: Worksheet 1 is the chlorophyll data Worksheet 3 is the location data CHLOROPHYLL DATA Column A is sample name, the first letter refers to the location data in worksheet 3, the second to the ice flow number and the third to the replicate number Section refers to depth in ice core, measured from the bottom Ignore C Column D is the total volume of melted ice Column E is the volume of D that was filtered Column G is the Fluorometer reading before the addition dilute HCl Column H is the fluorometer reading after the addition of acid Column I is the calculation of chlorophyl concentration in the sample Column K is areal chlorophyll estimate Column L is the mean for the core Column N is the mean for the site Column O is the standard deviation LOCATION DATA Lat, longs and times of each sampling. The first set (B-G) refers to the time sampling started, the second (H-M) to when it finished Project objectives: - Determine the net photosynthesis and primary productivity of the phytoplankton and major sea ice algal communities of the Eastern Antarctic Sea Ice Zone (SIZ). Estimate seasonal and annual algal production and inter annual variability - Obtain data on biomass distribution and variability to establish regional relationships between ice thickness, snow cover, and biomass - Determine the effects of a) Light b) Nutrients (principally nitrate and iron) c) Temperature on photosynthesis and primary production - Determine whether the biomass and productivity of the phytoplankton and sea ice algae in winter and spring limits the biomass or growth of krill - Estimate the effects of climate change on Sea ice Zone primary production Taken from the 2008-2009 Progress Report: Progress against objectives: This project used V2, a spring voyage, to collect underway data to determine surface biomass and primary production. Biomass samples (chlorophyll a) were taken every 3 hours. Productivity estimates by PAM were also made every 3 hours. Productivity measurements by FRRF were made every 1 minute. Nutrient samples were taken at the same time as the biomass samples. Analysis of the biomass samples is complete. Preliminary analysis of the productivity data has commenced. This data is being used for a Masters project (Rob Johnson, IASOS). An iron addition experiment accompanied this monitoring. Iron was added to samples taken every 3 hours and the change in photosynthesis (maximum quantum yield) measured with a PAM. The rate of recovery from iron stress was the principal focus. Most of this data has been submitted as metadata. Using The PAM and FRRF simultaneously also enabled a comparison to be made between these different ways of measuring photosynthesis. Progress was also made on the analysis of FRRF productivity and biomass data collected over several years on the L'Astrolabe transect. Analysis involves quantitative manipulation of FRRF data and correlation with chlorophyll, nutrients, temperature and other biological parameters. A publication arising from this work will be submitted this year. Taken from the 2009-2010 Progress Report: Progress against objectives: We participated in V1 of the Aurora Australis, spring 2009. The objective of this project was to measure surface primary production off East Antarctica. Photosynthetic parameters of phytoplankton under actinic light (L) as well as in darkness (D) were measured using a fast repetition rate fluorometer (FRRF). The parameters included the maximum photochemical efficiency (Fv/FmL,D), the functional absorption cross section of photosystem II (sPSII,L,D) and a turnover time of electron transfer (tL,D). Chlorophyll a concentration was measured by using Turner fluorometer. The photosynthetic parameters, irradiance and chlorophyll a concentration will then be used to estimate primary production of phytoplankton. This field program particularly focussed on the first of the listed objectives, ie 'Determine the net photosynthesis and primary productivity of the phytoplankton and major sea ice algal communities of the Eastern Antarctic Sea Ice Zone (SIZ). Estimate seasonal and annual algal production and inter annual variability'. We have been collecting FRRF-based primary production data from each season and the 2009 data provides the late spring data to supplement data from autumn, winter and summer, collected in previous seasons. We have now built up a comprehensive assessment of season variability which will enable a reliable estimate of annual primary production. These analyses will also provide a detailed snap shot of primary production with which to compare future changes. Preliminary analysis shows clear patterns of variation in Fv/Fm, a parameter that is particularly sensitive to low iron concentration. This data is shown on an accompanying diagram. Productivity analysis is still underway. Much of the work for this project forms part of the PhD project of Cheah Wee.Wee is expected to finish his PhD by December 2010 and it is anticipated that all data analysis for the project will have been completed and the finished manuscripts submitted for publication. He has already had one manuscript form this project accepted (Cheah et al, 2010).

A collection of about 20 isolates of Antarctic microalgae from the Windmill Islands region, around Casey Station has been established in the University of Malaya Algae Culture Collection (UMACC). The Antarctic microalgae in the collection includes Chlamydomonas, Chlorella, Stichococcus, Navicula. Ulothrix and Chlorosarcina. Comparative studies on the effect of global warming and UVR stress on these Antarctic microalgae and the tropical collection are being conducted. From the abstract of one of the referenced papers: The growth, biochemical composition and fatty acid profiles of six Antarctic microalgae cultured at different temperatures, ranging from 4, 6, 9, 14, 20 to 30 degrees C, were compared. The algae were isolated from seawater, freshwater, soil and snow samples collected during our recent expeditions to Casey, Antarctica, and are currently deposited in the University of Malaya Algae Culture Collection (UMACC). The algae chosen for the study were Chlamydomonas UMACC 229, Chlorella UMACC 234, Chlorella UMACC 237, Klebsormidium UMACC 227, Navicula UMAC 231 and Stichococcus UMACC 238. All the isolates could grow at temperatures up to 20 degrees C; three isolates, namely Navicula UMACC 231 and the two Chlorella isolates (UMACC 234 and UMACC 237) grew even at 30 degrees C. Both Chlorella UMACC 234 and Stichococcus UMAC 238 had broad optimal temperatures for growth, ranging from 6 to 20 degrees C (growth rate = 0.19 - 0.22 per day) and 4 to 14 degrees C (growth rate = 0.13 - 0.16 per day), respectively. In constrast, optimal growth temperatures for Navicula UMACC 231 and Chlamydomonas UMACC 229 were 4 degrees C (growth rate = 0.34 per day) and 6 to 9 degrees C (growth rate = 0.39 - 0.40 per day), respectively. The protein content of the Antarctic algae was markedly affected by culture temperature. All except Navicula UMACC 231 and Stichococcus UMACC contained higher amount of proteins when grown at low temperatures (6-9 degrees C). The percentage of PUFA, especially 20:5 in Navicula UMACC 231 decreased with increasing culture temperature. However, the percentages of unsaturated fatty acids did not show consistent trend with culture temperature for the other algae studied. There are three spreadsheets available in the download file. ASAC_2590 - provides detail about where each species of algae was collected from. ASAC_2590a - provides data from Teoh Ming-Li et al (2004) ASAC_2590b - provides data from Wong Chiew-Yen et al (2004) The fields in this dataset are: Isolate Culture Collection number Origin (Location) Fatty acids saturated fatty acids polyunsaturated fatty acids monounsaturated fatty acids Temperature growth rate PAR UVB

---- Public Summary from Project ---- Heard Island offers scientists a unique subantarctic laboratory for investigating climate change. We will establish a reference set of microalgal floras from lakes and lagoons and ultimately use the microalgal floras of today to investigate changes in fossil microalgal communities of Heard Island lake and lagoonal ecosystems to better understand regional subantarctic climate changes. Sediments were sampled with hand corers. Water samples were collected with a Niskin bottle. The dataset contains a summary of the locations data were sampled from, as well as average isotope concentrations from each sampling location. The fields in this dataset are: Date Location Salinity pH GPS Isotopes Concentration (ppb)

Sediment samples were collected with an Eckamn grab from four locations within the Windmill Islands (Herring Island, O'Connor Island, Shannon Bay and Brown Bay). A weekly sampling program was performed over a 10 week period, however not all locations could be accessed each time due to sea-ice conditions. All samples were collected at an 8 m water depth. Preliminary analysis of fortnightly samples are presented here. Diatom data are given as relative abundances of benthic diatom species. The abbreviations used to identify species are explained in the accompanying file sp_list. This work was completed as part of ASAC project 1130 (ASAC_1130) and project 2201 (ASAC_2201). Public summary from project 1130: Algal mats grow on sea floor in most shallow marine environments. They are thought to contribute more than half of the total primary production in many of these areas, making them a critical food source for invertebrates and some fish. We will establish how important they are in Antarctic marine environments and determine the effects of local sewerage and tip site pollution. We will also investigate the impact on the algal mats of the additional UV radiation which results from the ozone hole. Public summary from project 2201: As a signatory to the Protocol on Environmental Protection to the Antarctic Treaty Australia is committed to comprehensive protection of the Antarctic environment. This protocol requires that activities in the Antarctic shall be planned and conducted on the basis of information sufficient to make prior assessments of, and informed judgements about, their possible impacts on the Antarctic environment. Most of our activities in the Antarctic occur along the narrow fringe of ice-free rock adjacent to the sea and many of our activities have the potential to cause environmental harm to marine life. The Antarctic seas support the most complex and biologically diverse plant and animal communities of the region. However, very little is known about them and there is certainly not sufficient known to make informed judgements about possible environmental impacts. The animals and plants of the sea-bed are widely accepted as being the most appropriate part of the marine ecosystem for indicating disturbance caused by local sources. Attached sea-bed organisms have a fixed spatial relationship with a given place so they must either endure conditions or die. Once lost from a site recolonisation takes some time, as a consequence the structure of sea-bed communities reflect not only present conditions but they can also integrate conditions in the past. In contrast, fish and planktonic organisms can move freely so their site of capture does not indicate a long residence time at that location. Because sea-bed communities are particularly diverse they contain species with widely differing life strategies, as a result different species can have very different levels of tolerance to stress; this leads to a range of subtle changes in community structure as a response to gradually increasing disturbance, rather than an all or nothing response. This project will examine sea-bed communities near our stations to determine how seriously they are affected by human activities. This information will be used to set priorities for improving operational procedures to reduce the risk of further environmental damage. The fields in this dataset are: Species Site Abundance Benthic Date Location

The breeding population of the black-browed albatross Thalassarche melanophrys has increased at Heard Island since the first census data were obtained in 1947/1948. Four breeding localities are known, and all populations have increased in the period 1947/1948-2000/2001. The breeding population is estimated to have been approximately 200 pairs in 1947/1948. Based on 2000/2001 census data, the population has increased to a minimum of approximately 600 pairs over the 53 years. Two mechanisms, that of increased prey availability through scavenging discards from trawlers operating within their foraging range, and climatic amelioration, are proposed as hypotheses for this increase. The fields in this dataset are: Season Dates Location Numbers Nests Adults Chicks

Sediment samples were collected from four locations within the Windmill Islands (Cloyd Island, Odbert Island, Shannon Bay and Brown Bay). Within each location three parallel transects were created, with samples taken at set depths along each transect. At the time of collection, both surface and benthic irradiance levels were measured, and the % of surface irradiance that reached the sediment-water interface was calculated. Samples were analysed for benthic diatom abundances (expressed as relative abundances), and grain-size (expressed as % of total weight). The diatom spreadsheet (diatom_data)lists the relative abundance of benthic species. The abbreviation used to identify species are explained in the separate file called sp_list. Samples are identified XTYZ where X is the first letter of the location, Y indicates the sampling position along the transect and z indicates the transect (a, b or c). The benthic sheet is the relative abundances of benthic species. The greater than 2% sheet lists all the species that reach abundances greater than2% in at least 1 sample. The table sheet has the same info as greater than 2% but arranged by the individual locations. In this sheet (tables), measurements in m represent the depth of the water column overlying the position where the sediment samples were collected. (ie it was at different locations, not different water depths in the one spot). Sampling positions reflect increasing depth. At Brown Bay and Odbert Island, sediment samples were collected below water columns/water depths of 1, 2, 4, 8 and 12 m. At Cloyd Island, samples were collected from 4,6,8 and 12 m water depths. At Shannon Bay samples were collected from 2, 4, 8, and 12 m water depths. Details of the environmental parameters examined (grainsize and light) are given in the file labelled 'env_data' This work was completed as part of ASAC project 1130 (ASAC_1130). Public summary from project 1130: Algal mats grow on sea floor in most shallow marine environments. They are thought to contribute more than half of the total primary production in many of these areas, making them a critical food source for invertebrates and some fish. We will establish how important they are in Antarctic marine environments and determine the effects of local sewerage and tip site pollution. We will also investigate the impact on the algal mats of the additional UV radiation which results from the ozone hole. The fields in this dataset are: Diatom Spreadsheet Species Site Location Transect Depth (m) Environmental Data Spreadsheet Location Transect Depth (m) Grain size Gravel Sand Mud Light

Underwater vocalisations of Weddell seals were recorded at Casey (1997) and Davis (1992 and 1997) Antarctica. The goal of the study was to determine if it would be possible to identify geographic variations between the Casey and Davis seals using easily measured, narrow bandwidth calls (and not broadband or very short duration calls). Two observers measured the starting and ending frequency (Hz), duration (msec) and number of elements (discrete sounds) of four categories of calls; long duration trills, shorter descending frequency whistles, ascending frequency whistles and constant frequency mews. The statistical analyses considered all calls per base, single and multiple element calls, and individual call types. Except for trills, discriminant function analysis indicated less variation between the call attributes from Davis in 1992 and 1997 than between either of the Davis data sets and Casey 1997. The data set contains measures from 2966 calls; approximately 1000 calls per base and year. Up to 100 consecutive calls were measured from each recording location per day of recording so the data set indicates the relative occurrence of each of the call types per base and year. There were very few ascending whistles at Casey. All of the trills and mews contained a single element. This data set was published in Bioacoustics 11: 211-222. The fields in this dataset are: Observer Station Location Time Call Number Call Type Frequency Duration Elements Overlap In 2011, another download file was added to this record, providing recording locations made during the project in 2010. Furthermore: In 1997 Daniela Simon made some opportunistic recordings for the project near Casey. The recording locations were: Berkley Island 110 38'E, 66 12' 40"S Herring Island 110 40'E, 66 25'S O'Brien Bay 110 31'E, 66 18' 30"S Eyres Bay 110 32'E, 66 29" 20"S The Davis sites: IN 1990 THERE WAS ONLY ONE RECORDING SITE - 78 12.5' E, 68 31.6' S IN 1997 RECORDINGS WERE MADE AT THE FOLLOWING SITES EAST SIDE OF WEDDELL ARM - 78 07.55' E 68 32.17' S PARTIZAN ISLAND - 78 13.66' E 68 29.57' S LONG FJORD - 78 18.95' E 68 30.24' S TOPOGRAV ISLAND - 78 12.40' E 68 29.33'S OFFSHORE - 77 58.73'E 68 26.35'S TRYNE BAY - 78 26.25'E 68 24.87'S LUCAS ISLAND - 77 57.00'E 68 30.36'S WYATT EARP ISLANDS - 78 31.51'E 68 21.31'S ================================================================================ The attached document is "a listing of the Weddell seal breeding locations near Mawson where Patrick Abgrall in 2000 and Phil Rouget in 2002 made underwater recordings". The sound recording effort in 2000 was not as high as it was in 2002, hence fewer locations are listed. The Abgrall sites are referred to in the paper 'Variation of Weddell seal underwater vocalizations over mesogeographic ranges' that Abgrall, Terhune Burton co-authored, published in Aquatic mammals in 2003. This paper also refers to the Casey and Davis sites above. The Rouget sites relate to the metadata record 'Weddell Seal underwater calling rates during the winter and spring near Mawson Station, Antarctica' Entry ID: ASAC_1132-1 In general the seals can create breathing holes in areas where tide cracks form, namely close to grounded icebergs, the shoreline and islands. I doubt that they could/would create breathing holes through solid 2 m ice.

Antarctic lake cores record a history of precipitation in the preservation of climate sensitive microbial communities. Comprehensive integration of our precipitation records with other climate proxies such as ice core temperature records and historical climate data are dependent upon accurate dating of this lake sediment. Fourteen lakes and ponds of the Windmill Islands were sampled in 1998 for diatoms and in 1999 for water chemistry. The waterbodies included in this study fall into one of 3 broad categories: saline lake (greater than 5m deep; greater than, or equal to, 3 parts per thousand - salinity), saline pond (less than 5m deep; greater than, or equal to, 3 parts per thousand - salinity) or freshwater pond (less than 5m deep; less than 3 parts per thousand - salinity). Saline Lakes Beall Lake, the largest lake on Beall Island, is situated in a rocky catchment with evidence of breeding penguin pairs nearby. Outflow into the small lake on the northwestern point of Beall Lake occurs at elevated lake levels. Holl Lake, the largest lake on Holl Island, is contained by ridges to the NE and SW with an obvious outflow to the SE. At the time of sampling (20 Dec 1998), penguin feathers were observed in the sediment. In 2001 large numbers of penguins were observed behind the NE ridge in addition to the numerous skuas nesting on most nearby peaks. Lake A is the westernmost lake on Browning Peninsula. This large closed saline lake has a very thick ice cover (~2.5 m) and very little evidence of birdlife. Lake M is the easternmost lake sampled on Browning Peninsula. This large closed saline lake had a very thick ice cover (3.0 m) at the time of sampling. Saline Ponds Lake Warrington is the largest waterbody on Warrington Island. Found in the centre of Warrington Island, this small shallow (1.9 m) saline pond was almost completely frozen (ice cover of 1.6 m), with ca. 0.3 m of water below the ice at the time of sampling. The lake catchment is muddy with runoff towards Robertson Channel (to the NE) and the ice cover showed signs of sediment entrapment giving a gritty texture. Lake G is located on northeastern Peterson Island. This very saline (greater than 60 ppt) shallow (1.0 m) pond was almost completely frozen (ice cover of 0.8 m), with ca. 0.1 m of water below the ice at the time of sampling. Lake G is close to breeding penguin sites and there was a noticeable discolouration of the surface water at the time of sampling. Lake I is the easternmost of the three sites visited on southern Peterson Island. This shallow (0.3 m) saline pond is very close to breeding penguin sites and was sampled by hand as the ice cover (0.1 m) was almost as thick as the lake depth. Lake K is approx. 400 m to the west of Lake I on central southern Peterson Island. This completely frozen saline pond is also very close to breeding penguin sites. Lake L is the southernmost pond sampled on Peterson Island. This almost completely frozen shallow (~0.8 m/0.8 m ice cover) saline pond is very close to breeding penguin sites with noticeable discolouration of the top ca. 0.2 - 0.3 m of water at the time of sampling. Freshwater Ponds Lake B, a shallow (0.9 m) freshwater pond, is located on the western side of Browning Peninsula, approx. 500 m to the south of Lake A. Lake C is a shallow (1.0 m) freshwater pond in the central valley of Browning Peninsula. Lake D is a shallow (0.5 m) freshwater pond in the central valley of Browning Peninsula approx. 500 m to the north of Lake C. This lake was sampled by hand as the ice cover (~0.5 m) was almost as thick as the lake depth. Lake E is a shallow (3.1 m) freshwater pond in the central valley of Browning Peninsula approx. 250 m to the north of Lake D. Lake F is the northernmost pond sampled from the central valley of Browning Peninsula. This freshwater pond is approx. 500 m to the north-west of Lake E. The sediment/species samples were collected in November and December 1998, the water samples were collected in December 1999. The fields in this dataset are: Lake Name Code Location Latitude Longitude Lake Depth Ice Depth Water Sample Salinity Lake Area Catchment Elevation Nitrite Nitrate Silicon Phosphate pH Species The numbers given in the species spreadsheet are for percentage abundance, ie the relative abundance of each species in the community.

The following are excerpts from Ensor and Bassett (1987). A census by counts and estimates of Adelie penguin chicks on the George V Land coast of Antarctica between Commonwealth Bay and Buchanan Bay was undertaken during January 1982. Sections of colonies were photographed for comparison with photographs taken in 1913 during the Australasian Antarctic Expedition; positions and sizes of sub-colonies appeared unchanged after an interval of 68 years. Observations on the distribution of breeding Antarctic fulmars, Cape petrels, Snow petrels, Wilson's storm-petrels and South polar skuas are presented. This report describes the breeding status of seabirds, particularly Adelie penguins, on the George V Land coast of Antarctica between Commonwealth Bay (67 degrees S, 142.5 degrees E) and Buchanan Bay 67.1166 degrees S, 144.6666 E). The area was visited in January 1982 during the Mawson anniversary expedition of the Oceanic Research Foundation (ORF) on the schooner Dick Smith Explorer. The observations on the breeding of seabirds were conducted as a contribution to the International Survey of Antarctic Seabirds (ISAS) designed to investigate the abundance and distribution of seabirds in the Southern Ocean ecosystem. Of particular interest to this program is the the population status of Adelie penguins Pygoscelis adeliae. The George V Land coast has seldom been visited. The main expeditions to the area have been the 1911-13 Australasian Antarctic Expedition (AAE) and the 1929-31 British, Australian and New Zealand Antarctic Research Expedition (BANZARE). Falla (1937) summarised the biological observations made during these expeditions, including estimates of the numbers of Adelie penguins breeding in the Cape Denison area (67 degrees S, 142.6666 degrees E). The Australian National Antarctic Research Expeditions and Expeditions Polaires Francaises have also made visits. The present observations provide a recent estimate of the breeding population of Adelie penguins in the area. Since the authors' visit to the colonies was late in the breeding season, estimates of numbers were restricted to chicks. The number of chicks gives an approximation of the number of pairs of penguins breeding but due to annual variations in breeding success, these estimates are not as reliable as the direct counts of occupied nests that can be made during the incubation period. The 1981-82 ORF expedition was based at Cape Denison between 11 and 30 January 1982 where a census of Adelie penguin chicks and observations on the breeding of other birds was conducted. A camp was established on the Mackellar Islands (66.9666 degrees S, 142.65 degrees E) from 12 to 14 January to enable a census of penguin chicks to be made. On 30 January the expedition departed Cape Denison towards the Mertz Glacier tongue (154.3333 degrees E). The cruise track of the vessel followed approximately the outer limit of islets of the Way Archipelago (143.6666 degrees E) and passed close to Moyes Islands (143.85 degrees E) and Hodgeman Islands (144.25 degrees E). Brief visits were made to two islets in the Way Archipelago, Stillwell Island (143.8 degrees E) and an unnamed islet near Garnet Point (143.7666 degrees E). En route to the Mertz Glacier, a planned landing at Cape Hunter (66.95 degrees S, 142.3333 degrees E) to investigate the breeding population of seabirds including a large colony of Antarctic petrels Thalassoica antarctica (Falla 1937), had to be abandoned due to the onset of high winds. Adelie Penguin, Pygoscelis adeliae Locations of Adelie penguin colonies and counts and estimates of the numbers of chicks in each colony are given in a spreadsheet available at the url below. The total numbers of Adelie penguin chicks on the coast between Cape Denison and Buchanan Bay was 55,242. At Cape Denison, on the Mackellar Islets and on Stillwell Island, direct counts of chicks were made. Counts were replicated until a 5% accuracy was achieved. To aid the counting, the distribution of guano (which approximates to the extent of the sub-colonies) was mapped. On 12 January at Cape Denison, the first day of the author's counts, chicks were not yet in creches and were still protected by adults at their nest sites. It was possible therefore to count the number of occupied nests, the number of single chicks and pairs of chicks. These counts were obtained for 14 sub-colonies and in 297 nests 413 chicks were recorded. The 4898 chicks counted in the whole of the Cape Denison colony should therefore represent 4898 x 297/413 = 5322 nests at this stage of the breeding season. The original number of pairs of penguins that bred at Cape Denison in the 1981-82 season was greater than 3522 by an unknown number. A more accurate estimate of the actual number of pairs of penguins that bred at Cape Denison in the 1981-82 season could not be made because the authors have no knowledge of breeding failure prior to their visit. Previous estimates for Cape Denison were over 5000 pairs in January 1931 (Falla 1937) and 2000 pairs in January 1974 (Horne 1983). The authors have not adjusted the number of breeding pairs at colonies other than Cape Denison because it appears there is a difference in the breeding success between colonies in this area. Circumstantial evidence for this was the retarded development of chicks observed at Cape Denison. On 12 January chicks were still protected by adults at their nest sites, while the following day on the Mackellar Islets 7 km away, large creches of chicks from previous seasons were far more abundant than at any of the other colonies visited, suggesting a higher mortality of chicks at this colony. A probable factor inducing the retardation of breeding and higher chick mortality at Cape Denison is the severe weather characteristic of this locality (Mawson 1915). The strong katabatic winds that prevail at Cape Denison lose much of their force before reaching the offshore islands. Photographs were taken at Cape Denison and on Greater Mackellar Islet and compared with those taken in the 1912-13 breeding season during the AAE (Falla 1937). The relative positions and sizes of the sub-colonies were very similar after an interval of 68 years. Unfortunately the authors did not have the opportunity to take a photograph to match that taken by Falla on Lesser Mackellar Islet in 1931, but comparison with the authors' sketch maps of the sub-colonies indicates that the sizes and positions of the sub-colonies are similar. Although the authors have no knowledge of the numbers of penguins that bred in other parts of these colonies in the 1912-13 and 1929-31 breeding seasons, the similarity of the sizes and positions of the sub-colonies suggests that the current breeding population at Cape Denison and on the Mackellar Islets is comparable to that present in 1911-13 and 1929-31. This implies that the breeding population of penguins on this part of the Antarctic coast has been relatively stable over some 70 years. On this basis it is likely that the previous estimates of numbers of breeding penguins on the Mackellar Islets, 100,000 pairs in the 1913-14 season and 200,000 pairs in 1930-31 (Falla 1937), were too high, as the authors' count was 27,130 chicks. During the authors' visit to the unnamed islet in the Way Archipelago there was insufficient time to conduct a census of chicks and so photographs were taken from which chicks were subsequently counted. Counts and estimates of chicks in breeding colonies at Cape Gray (66.85 degrees S, 143.3666 degrees E), Moyes Islands, Hodgeman Islands and islets of the Way Archipelago (apart from the two on which the authors landed) were conducted from the vessel and the colonies were mapped in detail. Chicks on islets near to the vessel were counted individually and estimates of chick numbers were made only when the colonies were too distant and individual chicks could not be counted. The accuracy of counts and estimates of chick numbers conducted from the vessel depended on the vessel's distance from the colonies, the terrain and aspect of the breeding areas and visibility. Sun glare and obstruction of view by other islets and icebergs sometimes affected visibility. Use of binoculars was restricted by vibrations of the vessel. Therefore the counts and estimates of number of chicks conducted from the vessel, during which only the colonies in view were considered, underestimated the actual number of chicks, since substantial proportions of some colonies were probably hidden from view. Cape Pigeon Rocks, for example, most probably have relatively large numbers of penguins nesting on their landward facing slopes. This is evidenced by well-defined penguin tracks leading up the snow slopes on the seaward facing aspect. Some islets were several miles from the vessel and although the identification of penguins breeding on them was not always possible, we assumed all were Adelie penguins. Photographs of the islets were taken for comparison with the author's field notes and a selection of these have been lodged with the Australian Antarctic Division. No penguins were observed breeding on the Laseron Islands (66.9833 degrees S, 142.8 degrees E), Blair Islands (66.8333 degrees S, 143.15 degrees E), Fletcher Island (66.8833 degrees S, 143.0833 degrees E), Hannam Islands (66.9166 degrees S, 142.95 degrees E) or on the Close Islands (67.05 degrees S, 144.55 degrees E). There appears to be a medium-sized colony of Adelie penguins at Cape Hunter, but weather conditions prevented getting close enough to make an estimate of the number of chicks present. Antarctic Fulmar, Fulmarus glacialoides About 190 Antarctic fulmar nests with chicks were found on Stillwell Island. Fulmars on nests were seen from the vessel on two other islands in the Way Archipelago. These islands had about 75 and 20 nests. Cape Petrel, Daption capense A single Cape petrel nest, containing one chick, was found on Stillwell Island. Snow Petrel, Pagodroma nivea Thirty occupied nests were found at Cape Denison, 4 on the Mackellar Islets and 10 on Stillwell Island. More nests certainly would have been present at Cape Denison, but nest sites are restricted on the islands. Wilson's Storm-Petrel, Oceanites oceanicus During a brief search at Cape Denison, 5 nests of Wilson's storm-petrels were located. Apparently suitable breeding habitat occurs over large areas at Cape Denison and many more nests probably exist. On Greater Mackellar Islet, 4 nests were found and on Lesser Mackellar Islet the authors found 7. More nests probably exist on each of these islets although suitable habitat is restricted. No nests were found on Stillwell Island, but many storm-petrels were seen flying about the island in the evening. Antarctic Prion Pachyptila desolata Antarctic prions were found nesting at Cape Denison in 1913 during the AAE, in the vicinity of John O'Groats near the eastern barrier. A pair was shot on 3 December and the specimens (no. 22083 and 22084) are now in the Australian museum, Sydney. One member of a second pair was shot on 10 December, but the specimen was lost in the water. On 11 December, a prion was found in a crevice under a rock, with bones and an egg, evidently from a previous season. On 16 December, two more eggs were found (Falla 1937). This is the only record of Antarctic prions breeding at the Antarctic continent, apart from the Peninsula region. During the evacuation of an ANARE party in February 1978, a small bird was found tangled in the radio aerial during dis-assembly. It was badly injured and was killed to prevent further suffering. It was placed under a rock. Early in 1981, it was retrieved and identified as an Antarctic prion (G.W. Johnstone, pers. comm.). The radio aerials were on the hill south of the Mertz memorial cross. This is the only record of an Antarctic prion at Cape Denison since the AAE. The authors spent several evenings watching for prions in the vicinity by John O'Groats, and searched for nests but saw no birds and found no nests. The status of Antarctic prions at Cape Denison remains enigmatic. South Polar Skua, Catharacta maccormicki South polar skuas were found breeding at all areas visited. Nests at Cape Denison (4), Greater Mackellar Islet (3), Lesser Mackellar Islet (3), Stillwell Island (3) and the unamed islet in the Way Archipelago (3) each contained one chick. Two of the birds breeding at Cape Denison and on on Lesser Mackellar Islet were banded. Two of these had Paris Museum bands and had been banded by French biologists at Dumont d'Urville 150 km to the west. The other bird was timid and its band number could not be read. The dataset consists of a spreadsheet of chick numbers by date and location, several locality maps and comparative photos. The fields in this dataset are: Location Date Chick Numbers