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A comparative analysis of life-history features and adaptive strategies of Arctic and subarctic seal species - who will win the climate change challenge?
PURPOSE: Understanding and predicting species range shifts is crucial for conservation amid global warming. This study analyzes life-history traits of four seal species (ringed (Pusa hispida Schreber, 1775), bearded (Erignathus barbatus Pallas, 1811), harp (Pagophilus groenlandicus Erxleben, 1777), and harbour (Phoca vitulina Linnaeus, 1758) seals) in the Canadian Arctic using data from Inuit subsistence harvests. Bearded seals are largest, followed by harp seals, harbour seals, and ringed seals. Seasonal blubber depth patterns show minimal variation in bearded seals, whereas harbour and ringed seals accumulate fat in open-water seasons and use it during ice-covered seasons. Endemic Arctic seals (ringed and bearded) exhibit greater longevity and determinate body growth, reaching maximum size by 5 years, while harbour and harp seals grow indeterminately, physically maturing around 10-15 years. Age of maturation varies, with ringed and harbour seals being more sensitive to environmental fluctuations. Most bearded seals reproduce successfully each year, while ringed seals exhibit more variability in their annual reproductive success. Analysis of isoprenoid lipids in liver tissue indicates that ringed and bearded seals rely on ice-algal production, whereas harp and harbour seals depend on open-water phytoplankton production. Bearded seals appear more specialized and potentially face less competition, while harp seals may adapt better to changing habitats. Despite expected range shifts to higher latitudes, all species exhibit tradeoffs, complicating predictions for the evolving Arctic environment. DESCRIPTION: This dataset contains the data reported in Steven H. Ferguson, Jeff W. Higdon, Brent G. Young, Stephen D. Petersen, Cody G. Carlyle, Ellen V. Lea, Caroline C. Sauvé, Doreen Kohlbach, Aaron T. Fisk, Gregory W. Thiemann, Katie R. N. Florko, Derek C. G. Muir, Charmain D. Hamilton, Magali Houde, Enooyaq Sudlovenick, and David J. Yurkowski. 2024. A comparative analysis of life-history features and adaptive strategies of Arctic and subarctic seal species - who will win the climate change challenge? Canadian Journal of Zoology 2024-0093.R1 The data set includes species, location, harvest date, sex, age, standard length, girth, fat depth, teste size, parity status, pregnancy status, corpora lutea (n), corpus albicans (n), follicles (n). This dataset includes raw, unfiltered, and unprocessed historical data provided by harvesters that have not been screened for outliers. Individual users should screen the data for their specific use. Cite these data as: Steven H. Ferguson, Jeff W. Higdon, Brent G. Young, Stephen D. Petersen, Cody G. Carlyle, Ellen V. Lea, Caroline C. Sauvé, Doreen Kohlbach, Aaron T. Fisk, Gregory W. Thiemann, Katie R. N. Florko, Derek C. G. Muir, Charmain D. Hamilton, Magali Houde, Enooyaq Sudlovenick, and David J. Yurkowski. 2024. Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, MB. https://open.canada.ca/data/en/dataset/ea9ff038-8b16-11ef-8cce-55cc7f028297
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Responses and adaptations by two seal species to variability in the Southern Ocean ecosystem
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Metadata record for data from ASAC Project 2753 See the link below for public details on this project. Public Weddell and southern elephant seals are high-order predators living in the Antarctic marine ecosystem. Their place in that ecosystem is the result of a long history of evolutionary adaptation to a challenging and changing environment. The objective of this study is to understand how Weddell and elephant seals have adapted and are responding to today's rapidly changing Antarctic environment. This study will use current and innovative approaches in demographic (population) analyses and diet techniques to analyse changes in the seals' demographic parameters and historical aspects of their ecology. Project objectives: Objective 1. Seek a greater understanding of the links between climate based environmental parameters and Weddell seal demographic performance. Objective 2. Test the hypothesis that the foraging ecology and presence of male southern elephant seals hauling out along the Antarctic coast are regulated by variation in the extent and concentration of coastal sea-ice. Objective 3. Examine contemporary and historical dietary shifts in an Antarctic marine predator by using a non-invasive technique, stable isotope analyses. Objective 4. Construct models of potential population performance for Weddell and southern elephant seals with predicted climate change Taken from the 2008-2009 Progress Report: Progress against objectives: The first season of field work was conducted at Casey in December 2008. This comprised of surveys of the region to locate breeding and moulting haulouts, weighing and flipper tagging of Weddell seal pups and flipper tagging of sub adult elephant seals. Specifically: Tagging Leptonychotes weddellii. A total of 30 pups were flipper tagged. Tagging: 46 sub-adult male Mirounga leonina in Browning Peninsula region. Aerial survey of the Casey fast-ice conducted on 30/1/2009. Conducted at 1000, 500, 300 ft. A total of 33 seals counted. Taken from the 2009-2010 Progress Report: Progress against objectives: 1. Observations of tagged Weddell seals made in the Vestfold Hills during the breeding season. 2. Counts were made of elephant seals at Davis station 3. No progress made due to postponement of project at Casey 4. Data collected on Weddell and elephant seals at Davis. No modelling undertaken in this year
Energy requirements and daily food consumption of crabeater seals in the Antarctic winter pack-ice
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Although the most abundant of all mammalian predators in the Antarctic marine ecosystem, crabeater seals are also one of the least understood. The most fundamental question of all - how many are there? - is the focus of an extensive international collaborative program (the Antarctic Pack-ice Seal Program, or APIS). This study supplements APIS by providing additional data on the diving behaviour and food requirements of crabeater seals, that can be used in conjunction with census data to provide information on the role of crabeater seals in the antarctic ecosystem. Winter densities and distributions of Crabeater seals were collected during 1999. Crabeater seals were most often encountered on the shelf break. The data collected include numbers of seals sighted per hour in relation to the amount of time the ship spent in each 0.5 degree grid square. This study is the first to describe the winter distribution of crabeater seals (Lobodon carcinophagus) in East Antarctica. The study was conducted in the Mertz Glacier Polynya region from July to August 1999. In total 89 crabeater seals were seen in 26 groups which ranged in size from 1 to 35 animals (mean = 3.2). The mean observed haulout density along a 200m wide strip transect was 0.108 seals per square kilometre, or 0.042 groups per square kilometre. Crabeater seals were not uniformly distributed in the polynya but selected areas of stable ice over shallow (less than 1000m) waters. We used a generalised linear model to assess the relationship of seal distribution to the physical attributes of sea ice concentration, thickness, and ocean depth. We found that ice thickness and ocean depth were the most important determinants of seal distribution. Crabeater seals occurred in areas where the ice affords them a stable haulout platform while allowing them access to Antarctic krill that live directly beneath the ice.
Winter foraging ranges of Weddell seals: a pilot study to assess their role in the winter sea-ice zone and their potential as ocean sampling platforms
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Metadata record for data from ASAC Project 2695 See the link below for public details on this project. Variations in the winter extent of sea ice are thought to have profound effects on biological productivity, such as algal growth and the reproduction of Antarctic krill, with subsequent flow-on effects through the food web. This pilot study aims to measure the winter foraging patterns of Weddell seals (Leptonychotes weddellii) as a first step in investigating their role in the winter sea-ice zone. Our specific objectives are to: Obtain satellite tracks from a sample of adult female Weddell seals Collect diving behaviour (dive depth, duration and frequency) from a sub-set of these seals Collect high precision water temperature data from a subset of these seals These data will enable us to assess the feasibility of including Weddell seals as a candidate species in a long-term study of winter sea-ice and predator performance. This project has now been merged into project number 2794 (ASAC_2794). It also contains data collected as part of project 1171 (ASAC_1171). The download file contains 13 Access Databases containing data from this project. An excel spreadsheet summarising the databases is also included. The data have also been loaded into the Australian Antarctic Data Centre's ARGOS tracking database. The database can be accessed at the provided URL.
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
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
Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii) in breeding and nonbreeding situations
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During the winter and spring of 2000 and 2002, underwater calls of Weddell seals were recorded near Mawson. The goal was to determine if some call types were only given during the spring breeding season. The calls were classified into 10 broad types and the proportional usage of each was determined from May to December. All call types were present throughout the study period and during periods of darkness and light and at high, medium or low calling rates. Taken from the abstract of the referenced paper: Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii (Lesson, 1826)) near Mawson, Antarctica, investigated the hypothesis that certain call types function specifically in breeding behaviour. Recordings were collected at various sites in 2000 and 2002 from June to December. Twenty-four hour recordings were collected in 2002 at two sites. One hundred consecutive calls from each of 248 recordings were classified into one of ten common call types. Time to 100 calls provided the calling rate. The study period was divided into four periods representing initial sea-ice formation, pre-pupping, pupping, and mating. Calling rate and light-dark differences were also examined. No presence-absence differences were observed for any of the call types with season. The largest difference between nonbreeding and breeding situations was an increase from 32.2% to 38.1% for descending whistles (F[3,244] = 4.483, p = 0.004). Trills gradually increased from 1.8% to 7.3% toward the mating period (F[3,244] = 30.932, p less than 0.001). The proportion of trills, chugs, descending whistles, and other call types also varied with calling rate and light-dark conditions. Some pre-reproductive behaviours may occur in winter, but no call types of Weddell seals function solely in the breeding season.
Foraging ecology of fur seals at Iles Kerguelen
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Public summary for project 2128: The aim of this study is to relate the foraging behaviour of Antarctic fur seals breeding on the Kerguelen Plateau at Iles Kerguelen and Heard Island, to the distribution of prey species at sea. Specifically this project seeks to examine the relationship between predators and prey, and how their locations at sea vary according to the position of major productive zones, such as the Antarctic Polar Frontal Zone. This project will provide important data on the relationship between predators and their prey and the developing commercial fisheries in the region. These data are central to improved conservation and management of marine resources on the Kerguelen Plateau. Variations made to the work plan The original comparative aspects of the program planned for the 1999/00 season, where fur seals from Iles Kerguelen and Heard Island were to be satellite tracked simultaneously could not be undertaken because of original 1999/00 field season to Heard Island was re-scheduled to 2000/01. Fortunately the project collaborator Dr Christophe Guinet (French CEBC-CNRS) agreed to extend the work program at Iles Kerguelen another season, and the comparative and integrated fur seal-prey-fisheries study over the Kerguelen Plateau was undertaken the following season (2000/01). Details of this study are presented in ASAC project 1251 (CI - Goldsworthy)and 1085 (CI-Robertson). Significant findings: The distribution of the foraging activity of Antarctic fur seal females was investigated at Cap Noir (49 degrees 07 S, 70 degrees 45E), Kerguelen Island in February 1998. Eleven females were fitted with a satellite transmitter and Time Depth recorder. The two sets of data were combined to locate spatially the diving activity of the seals. The fish component of the fur seal diet was determined by the occurrence of otolotihs found in 55 scats collected during the study period at the breeding colony. Oceanographic parameters were obtained simultaneously through direct sampling and satellite imagery. The mesopelagic fish community was sampled on 20 stations along four transects where epipelagic trawls were conducted at night at 50 meters of depth. We then investigated, using geographic information systems, the relationship between the spatial distribution of the diving activity of the fur seals and oceanographic factors that included sea surface temperature, surface chlorophyll concentration, prey distribution and bathymetry obtained at the same spatio-temporal scale as the spatial distribution of the diving activity of our study animals. An inverse relationship was found between the main fish species preyed by fur seal and those sampled in trawl nets. However, the diving activity of Antarctic fur seal females was found to be significantly related to oceanographic conditions, fish-prey distribution and to the distance from the colony but these relationships changed with the spatial scale investigated. A probabilistic model of the Kerguelen Plateau was developed that predicted where females should concentrate their foraging activity according to the oceanographic conditions of the year, and the locations of their breeding colonies. Maternal allocation in growth of the pup was measured in Antarctic fur seals (Arctocephalus gazella) at Iles Kerguelen during the 1997 austral summer. Absolute mass gain of pups following a maternal foraging trip was independent of the sex of the pup but was positively related to the foraging trip duration and to maternal length. However, daily mass gain, i.e. the absolute mass gain of the pup divided by the foraging trip duration, decreased with increasing foraging trip duration but increased with maternal length. While fasting, the daily mass loss of the pup was related to the sex of the pup and initial body mass, with both heavier pups and female pups losing more mass per day than lighter pups and male pups. The mass specific rate of mass loss was significantly higher in female pups than in male
Stereotyped Calling Patterns of a Male Weddell Seal (Leptonychotes weddellii)
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From the abstract of the attached paper: Underwater calling behaviour between breathing bouts of a single adult male Weddell seal (Leptonychotes weddellii) was examined with respect to call type and timing late in the breeding season at Davis Station, Antarctica. Underwater calls and breathing sounds were recorded on 1 and 8 December 1997. Thirty-seven sequences of calls prior to surfacing to breathe and 36 post-submerging sets of calls were analysed with respect to probability of call type occurrence and timing. Dives were 461 plus or minus 259 seconds (mean plus or minus standard deviation). The seal called every 29.7 plus or minus 56.2 seconds throughout a dive. The first call after submerging was usually (n = 29 of 36) a low frequency (less than 0.8 kHz) growl. Three patterns of three- to five-call type sequences were made following 28 of 36 breathing bouts. Call type patterns after submerging exhibited fewer different sequences than those before surfacing (chi-squared = 61.42, DF = 4, p less than 0.000001). The call usage patterns before surfacing were diverse and did not indicate when the seal was going to surface, a time when he would be vulnerable to attack from below. Our findings suggest the hypotheses that territorial male Weddell seals call throughout each dive and use stereotyped call patterns to identify themselves while vocally asserting dominance. This work was completed as part of ASAC project 2122 (ASAC_2122). The fields in this dataset are: Tape number Sequence per tape Sequence entire data Call types Count since last breath Last breathing bout number Count prior to next breath Time in tape (seconds) End time of last breath Start time of next breath Time since dive The 'sequence' relates to the sequence of call types that are given between the end of the last breath of a breathing bout and the beginning of the first breath the next time the seal surfaces to breathe. Essentially the report relates to the stereotyped nature of the call types, especially just after the dominant male dives after finishing breathing. Each time the animal surfaced, that was identified as a breathing bout. They are numbered sequentially. At the very start of the data set the seal had to surface before the breathing bout could be counted (as number 1). This procedure enabled us to identify the order and timing of the calls that occurred immediately before and immediately after each breathing bout. Thus, the 'count prior to the next breath' gives the order of the calls before the seal surfaced to breathe again (third last, second last, last,). The call types were analysed with respect to the following pattern: third last, second last, last, breathing bout, first, second, third, etc. to third last, second last, last, next breathing bout.
Reproductive rate as an index of the environment: 28 years of monitoring Weddell seals in east Antarctica.
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Publication of these results is currently in progress with the Journal of Animal Ecology. Summary 1.An efficient method of describing change in Antarctic marine ecosystems is long-term monitoring of land-breeding marine predators. High-level predators are used to index the state of environment on the notion that perturbations in the ecosystem will affect their diet, reproductive performance and other demographics. For this purpose, Weddell seals breeding at the Vestfold Hills have been marked and re-sighted for the past 28 years (1973 - 2000). 2.Successful reproduction requires considerable energetic resources. The difference between rates of conception and rates of parturition suggests pregnant females abort reproductive attempts when their energy stores are low. In this way, annual rates of reproduction (i.e. parturition) are a measure of foraging efficiency. 3.Previous attempts to estimate Weddell seal reproduction have been biased by different rates of re-sighting breeding and non-breeding females. We used multistate mark and re-sight models to account for this and other variables when estimating reproductive rate. 4.The amplitude of temporal variation was much greater for reproduction than for survivorship, indicating that parous (breeding) females maximised survival by reproducing less. This strategy could be successful in fluctuating environments because seals live longer and experience more reproductive occasions. 5.The population had low reproductive rates from 1983 to 1985 and throughout the 1990s. In those years, potential recruitment into breeding groups was reduced to 50 - 60 % of the cohort before viable pups were even born. 6.Even in years of low reproductive rate, typically half (52%) of the breeding females produced pups. It seemed that individuals differed in their foraging success and thus body condition and / or their functional response to this. 7.There was no evidence for costs of reproduction. We infer that the seals responded to environmental conditions prior to parturition, as opposed to proceeding with reproduction when inadequately resourced and depleting energy resources such that they had lower probability of surviving or reproducing the following year. 8.Synthesis and applications: This study demonstrates a method of estimating reproductive rate that overcomes bias inherent in traditional methods. Estimated in this way, we propose that reproductive rate is the best indicator of the state of marine ecosystems that can be indexed for Weddell seals. The fields in this dataset are: Year Standard Error Upper confidence interval Lower confidence interval Breeding probability Upper error bar Lower error bar
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