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  • 1
    Electronic Resource
    Electronic Resource
    Foraging strategies of incubating and brooding king penguins Aptenodytes patagonicus (1998)
    Springer
    Oecologia 114 (1998), S. 194-201 
    Details
    ISSN: 1432-1939
    Keywords: Key wordsAptenodytes patagonicus ; Breeding stage ; Diving ; Foraging strategy ; Penguin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For oceanic birds like king penguins, a major constraint is the separation of foraging areas from the breeding colony, largely because swimming increases foraging costs. However, the relationship between foraging strategy and breeding stage has been poorly investigated. Using time-depth recorders, we studied the diving behaviour of two groups of king penguins that were either incubating or brooding chicks at Crozet Islands (Southern Indian Ocean) at the same period of the year. Although birds with chicks had the highest predicted energy demand, they made foraging trips half as long as incubating birds (6 vs. 14 days) and modified their time and depth utilisation. Birds with chicks dived deeper during daylight (mean maximum depth of 280 m vs. 205 m for those incubating). At night, birds with chicks spent twice as much time diving as those incubating, but birds at both stages never dived beyond 30 m. Movements to greater depths by brooding birds are consistent with the vertical distribution of myctophid fish which are the main prey. As chick provisioning limits trip duration, it is suggested that it is more efficient for parents to change their diving patterns rather than to restrict their foraging range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050436
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Hypothermia in foraging king penguins (1997)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 388 (1997), S. 64-67 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The ability to dive for long periods increases with body size, but relative to the best human divers, marine birds and mammals of similar or even smaller size are outstanding performers. Most trained human divers can reach a little over 100 m in a single-breath dive lasting for ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/388064a0
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  • 3
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    Foraging strategy of King Penguins (Aptenodytes patagonicus) during summer at the Crozet Islands (1998)
    Ecological Society of America
    In:  Ecology, 79 (6). pp. 1905-1921.
    Details
    Publication Date: 2021-05-05
    Description: The foraging ecology of King Penguins (Aptenodytes patagonicus) at Possession Island, Crozet Archipelago, was studied between January and March 1993 and between February and March 1994. Diving activity and position of the birds were determined via externally attached logging units. Feeding behavior was detected using stomach temperature sensors. All calculated positions of the birds occurred south of Possession Island. The area most frequented was situated 250 km south of the island (48.5° S), where birds stayed for 40 h during a foraging trip, on average. The overall swim speed differed with time into the foraging trip, being lowest during the central part and highest (10 km/h) during the last night at sea, when birds were returning to the colony. Diving activities showed a clear diurnal pattern, with maximum dive depth being dependent on ambient light levels. During the night, only shallow dives 〈30 m were made, whereas deep dives occurred only during daylight. Preferred dive depths during deep diving ranged from 100 to 200 m. Maximum dive depth was 323 m, and maximum dive duration was 9.2 min. Vertical velocity (rate of change of depth) and dive duration were significantly correlated with increasing dive depth. Time spent at depth changed with time into the foraging trip, with most time being spent in deep water strata during the central phase, whereas predominately shallow dives were executed at the beginning and at the end of the foraging trips. Feeding success was closely linked to time of day, dive depth, and time into the foraging trip. Overall, 〉85% of the feeding events occurred during daylight and at twilight. Mean food mass ingested was calculated to be ∼2350 g/d, with the highest amounts ingested during the central and penultimate days of the foraging trip. Foraging success (grams ingested per unit time underwater) was also highest (〉370 g/h) at this time. The relationships between foraging strategy, inter‐ and intraspecific competition, and King Penguin body mass are discussed.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1890/0012-9658(1998)079[1905:FSOKPA]2.0.CO;2
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Foraging areas of king penguins (Aptenodytes patagonicus) breeding at Possession Island in the Southern Indian Ocean (2000)
    Marine Ornithology
    In:  Marine Ornithology, 27 . pp. 77-84.
    Details
    Publication Date: 2018-09-18
    Description: Between January and March 1994 and between January and June 1995 we used Global Location Sensors(GLS) to determine the feeding areas of King Penguins Aptenodytes patagonicus breeding at Possession Island, Crozet Archipalago. In both years, the preferred feeding area during summer was located about 300 km south of the island, being slightly more distant in 1995. Mean foraging trip duration was 5.7±1.1 days (n = 6) during summer 1994 and 8.9±3.7 days (n = 9) during summer 1995, respectively. During summer the travelling speed of the King Penguins studied was highest at the first and last days of the foraging trip (c. 8 km/h). During the middle days of foraging trips travelling speeds were much lower (〈 5 km/h). In early winter, between late April and mid-June 1995, two King Penguins equipped with GLSs executed foraging trips with durations of 53 and 59 days, respectively. Both birds travelled beyond 60°S with maximum distances to the colony of 1600 and 1800 km, respectively, and total distances covered of about 5000 km. The winter trips were characterized by alternating periods of higher and lower distances covered, indicating a highly variable feeding success at different localities. The relationships between foraging trip duration (days) and maximum distance to the colony (km) and total distance covered (km) were calculated to be maximum distance = 210 + 27 d and total distance = 340 + 85 d.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground (2016)
    Royal Society
    Details
    Publication Date: 2016-12-23
    Description: Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry 〈 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll- a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.
    Keywords: behaviour, ecology, environmental science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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    PAPER CURRENT
  • 6
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    Observing the Antarctic continental shelf with CTD-instrumented elephant seals (2016)
    In:  EPIC330th Forum for Research into Ice Shelf Processess (FRISP), Gothenburg, Sweden, 2016-10-04-2016-10-06
    Details
    Publication Date: 2019-10-04
    Description: Since 2004, several hundreds of diving marine animals, mainly Antarctic and Arctic seals, were fitted with a new generation of Argos-CTD tags developed by the Sea Mammal Research Unit of the University of St. Andrews in Scotland. These tags can be used to investigate simultaneously the at-sea ecology of these animals while collecting valuable oceanographic data. Some of these species are able to travel thousands of kilometres, continuously diving to great depths (590 ± 200 m, with maxima around 2000m). Through the years, these animals have become an essential source of temperature and salinity profiles (MEOP-CTD database available at http://www.meop.net), especially for the polar oceans, complementing efficiently the Argo array. One region where the use of instrumented seals has been particularly successful is the Antarctic continental shelf. Recent contributions to the study of the Antarctic Bottom Water production area near Prydz Bay, the rapidly-thinning ice shelves in Amundsen Bay, or the stratification in the marginal ice zone, are demonstrating the rapidly growing value of these data for Polar Research.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 7
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    Elephant Seals reveal frontal structure and sea ice formation rates in the Southern Ocean (2008)
    In:  EPIC3SCAR/IASC Open Science Conference, 8.-11. July 2008, St. Petersburg, Russia.
    Details
    Publication Date: 2019-07-17
    Description: Due to the low accessibility of the region, most of the seasonally ice-covered Southern Ocean remains unobserved during winter. Here we show that southern elephant seals (Mirounga leonina), equipped with oceanographic sensors, can measure winter hydrography with unprecedented temporal and spatial resolution. Seals provided a 30-fold increase in hydrographic profiles from the sea ice zone, allowing the major fronts to be mapped south of 60°S. Sea-ice formation rates in the East Antarctic sector were estimated from salinity increase in the upper water column and compared to simulations with a circumpolar finite-element sea-ice ocean model. From the observations, peak freezing rates of 2.5-3 cm/d were estimated for the period from late April to early May during the rapid northward expansion of the ice cover. While the pack ice becomes more compact, sea ice formation declines to 1 cm/d in June/July, and virtually stops by the end of August, when the maximum ice extent is reached. Modeled and observed freezing rates agree remarkably well, so that the model can be used to complete the seasonal cycle. By sampling the ocean during winter, elephant seals fill a blind spot in our sampling coverage, bringing us closer to a truly global ocean observing system.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 8
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    Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals (2008)
    In:  EPIC3Proceedings of the National Academy of Sciences (PNAS), 105(33), pp. 11634-11639
    Details
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 9
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    Estimates of the Southern Ocean general circulation improved by animal-borne instruments (2013)
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, 40(23), pp. 6176-6180, ISSN: 0094-8276
    Details
    Publication Date: 2014-04-02
    Description: Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixedlayer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 10
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    Differences in patterns of habitat utilization of Weddell and crabeater seals along their circumpolar distributions: responding to local conditions (2014)
    In:  EPIC35th Bio-logging Science Symposium, Strasbourg, France, 2014-09-22-2014-09-26
    Details
    Publication Date: 2014-11-24
    Description: Addressing the potential changes in species distribution in response to global change requires evaluating current species-wide patterns of habitat utilization and how these are determined by the local environment. These efforts, however, can be limited by a lack of data on distribution of the species, which are particularly difficult to collect in the case of air-breathing marine predators in high latitude systems. We present here a retrospective analysis on the distributional patterns of both Weddell (Leptonychotes weddellii) and crabeater seals (Lobodon carcinophaga) throughout their circumpolar ranges, using satellite telemetry data obtained over a time span of three decades (1990 to 2010s). Raw Argos tracks (nWeddell = 132; ncrabeater = 115), were filtered using a Switching State Space Model, and the tracking-derived behaviors (transit, foraging) were used to construct localized habitat models based on sea ice and bathymetry derived variables using binary Generalized Additive Mixed Models. We found differences in the effects and significance that environmental covariates had on the distribution at the local scale. The development of local habitat models for the entire range of these species will allow us to understand the ability of each species to cope with the anticipated environmental changes in their habitat.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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