Ecology of Southern Elephant Seals
Metadata record for data from ASAC Project 257 See the link below for public details on this project. From the abstracts of some of the referenced papers: Anatomical and physiological studies of southern elephant seals (Mirounga leonina), particularly in the post-natal period, raise questions of rel...
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Australian Antarctic Data Centre
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Online Access: | https://researchdata.ands.org.au/ecology-southern-elephant-seals/699952 https://data.aad.gov.au/metadata/records/ASAC_257 http://nla.gov.au/nla.party-617536 |
id |
ftands:oai:ands.org.au::699952 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Research Data Australia (Australian National Data Service - ANDS) |
op_collection_id |
ftands |
language |
unknown |
topic |
biota oceans ISLANDS EARTH SCIENCE BIOSPHERE TERRESTRIAL ECOSYSTEMS WATER TEMPERATURE OCEAN TEMPERATURE SEALS/SEA LIONS/WALRUSES BIOLOGICAL CLASSIFICATION ANIMALS/VERTEBRATES MAMMALS CARNIVORES SPECIES LIFE HISTORY ECOLOGICAL DYNAMICS SPECIES/POPULATION INTERACTIONS POPULATION DYNAMICS elephant seals time depth recorder tdr diving foraging population FIELD SURVEYS OCEAN > SOUTHERN OCEAN SOUTHERN OCEAN > MACQUARIE ISLAND GEOGRAPHIC REGION > POLAR |
spellingShingle |
biota oceans ISLANDS EARTH SCIENCE BIOSPHERE TERRESTRIAL ECOSYSTEMS WATER TEMPERATURE OCEAN TEMPERATURE SEALS/SEA LIONS/WALRUSES BIOLOGICAL CLASSIFICATION ANIMALS/VERTEBRATES MAMMALS CARNIVORES SPECIES LIFE HISTORY ECOLOGICAL DYNAMICS SPECIES/POPULATION INTERACTIONS POPULATION DYNAMICS elephant seals time depth recorder tdr diving foraging population FIELD SURVEYS OCEAN > SOUTHERN OCEAN SOUTHERN OCEAN > MACQUARIE ISLAND GEOGRAPHIC REGION > POLAR Ecology of Southern Elephant Seals |
topic_facet |
biota oceans ISLANDS EARTH SCIENCE BIOSPHERE TERRESTRIAL ECOSYSTEMS WATER TEMPERATURE OCEAN TEMPERATURE SEALS/SEA LIONS/WALRUSES BIOLOGICAL CLASSIFICATION ANIMALS/VERTEBRATES MAMMALS CARNIVORES SPECIES LIFE HISTORY ECOLOGICAL DYNAMICS SPECIES/POPULATION INTERACTIONS POPULATION DYNAMICS elephant seals time depth recorder tdr diving foraging population FIELD SURVEYS OCEAN > SOUTHERN OCEAN SOUTHERN OCEAN > MACQUARIE ISLAND GEOGRAPHIC REGION > POLAR |
description |
Metadata record for data from ASAC Project 257 See the link below for public details on this project. From the abstracts of some of the referenced papers: Anatomical and physiological studies of southern elephant seals (Mirounga leonina), particularly in the post-natal period, raise questions of relative musculature growth, control of metabolism, circulation and temperature regulation, which could be important in our understanding of these processes in mammals and of their contribution to adaptation to environmental extremes. The diving behaviour of 14 adult southern elephant seals was investigated using time depth recorders. Each of the seals performed some dives that were longer than its theoretical aerobic dive limit. Forty-four percent of all dives made by post-moult females exceeded the calculated limit compared with 7% of those made by postbreeding females and less than 1% of those made by adult males. The extended dives displayed characteristics that suggested they were predominantly foraging dives, although some were apparently rest dives. Dives longer than the calculated aerobic limits often occurred in bouts; the longest consisted of 63 consecutive dives and lasted 2 days. Postmoult females performed longer bouts of extended dives than postbreeding females. Extended surface periods (longer than 30 min) were not related to the occurrence of extended dives or bouts of extended dives. The possible physiological mechanisms that permit such prolonged continuous dives are discussed. Southern elephant seals may increase the aerobic capacity of dives by lowering their metabolism to approximately 40% of the resting metabolic rate on long dives. There is substantial interseal variability in the methods used to cope with long dives. Some animals appear to use phsyiological strategies that allow them to prolong the time available to them at the bottom of a dive, while others use alternative strategies that may limit the time available at the bottom of their dives. Fourteen time-depth-temperature recorders were recovered from adult southern elephant seals (Mirounga leonina) returning to Macqaurie Island to breed or moult. The resulting temperature/depth profiles indicated that all four males spent most of their time in waters lying over the Antarctic Continental Shelf, whereas only one of the ten females spent any time there. Five of the females foraged just off the Antarctic Continental Shelf, and the other five remained near the Antarctic Polar Front. 1) Mark-resight data were analysed for thirteen cohorts from a declining population of southern elephant seals branded at Macquarie Island between 1951 and 1965. 2) First year survival was essential stable during the 1950s at about 46% for females and 42% for males. There was a dramatic fall in first year survival during the 1960s, declinging to less than 2% for both sexes in 1965. Post-year-1 survival did not change between the 1950s and the 1960s. 3) Comparisons with a stable population of southern elephant seals at South Georgia indicated that both first year and adult survival were lower in the Macquarie Island population. There were no changes in the age at first breeding of the Macquarie Island seals during the study, but this was on average 1 year later than at South Georgia. 4) It is hypothesised that the current decline in elephant seal numbers at several of their major breeding islands is due to the populations returning to pre-sealing levels after they had risen to abnormally high levels with the end of commercial exploitation early this century. 5) Possible tests of the hypothesis include studying the diet and foraging behaviour of southern elephant seals to gain an understanding of the predator-prey relationships, continuing to census the Macquarie Island population to determine if the population levels out at around the estimated pre-sealing levels, and monitoring northern elephant seal populations which were also severely exploited but are currently increasing rapidly. |
author2 |
BRYDEN, MICHAEL M. (hasPrincipalInvestigator) BRYDEN, MICHAEL M. (processor) BURTON, HARRY (processor) HINDELL, MARK A. (processor) Australian Antarctic Data Centre (publisher) |
format |
Dataset |
title |
Ecology of Southern Elephant Seals |
title_short |
Ecology of Southern Elephant Seals |
title_full |
Ecology of Southern Elephant Seals |
title_fullStr |
Ecology of Southern Elephant Seals |
title_full_unstemmed |
Ecology of Southern Elephant Seals |
title_sort |
ecology of southern elephant seals |
publisher |
Australian Antarctic Data Centre |
url |
https://researchdata.ands.org.au/ecology-southern-elephant-seals/699952 https://data.aad.gov.au/metadata/records/ASAC_257 http://nla.gov.au/nla.party-617536 |
op_coverage |
Spatial: northlimit=-54.0; southlimit=-55.0; westlimit=158.0; eastLimit=159.0; projection=WGS84 Temporal: From 1987-09-30 to 1995-03-31 |
long_lat |
ENVELOPE(158.0,159.0,-54.0,-55.0) |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Southern Elephant Seals Southern Ocean walrus* |
genre_facet |
Antarc* Antarctic Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Southern Elephant Seals Southern Ocean walrus* |
op_source |
Australian Antarctic Data Centre |
op_relation |
https://researchdata.ands.org.au/ecology-southern-elephant-seals/699952 cde980e2-8b68-4456-9edf-5af9f129b151 ASAC_257 https://data.aad.gov.au/metadata/records/ASAC_257 http://nla.gov.au/nla.party-617536 |
_version_ |
1766245869531693056 |
spelling |
ftands:oai:ands.org.au::699952 2023-05-15T13:46:57+02:00 Ecology of Southern Elephant Seals BRYDEN, MICHAEL M. (hasPrincipalInvestigator) BRYDEN, MICHAEL M. (processor) BURTON, HARRY (processor) HINDELL, MARK A. (processor) Australian Antarctic Data Centre (publisher) Spatial: northlimit=-54.0; southlimit=-55.0; westlimit=158.0; eastLimit=159.0; projection=WGS84 Temporal: From 1987-09-30 to 1995-03-31 https://researchdata.ands.org.au/ecology-southern-elephant-seals/699952 https://data.aad.gov.au/metadata/records/ASAC_257 http://nla.gov.au/nla.party-617536 unknown Australian Antarctic Data Centre https://researchdata.ands.org.au/ecology-southern-elephant-seals/699952 cde980e2-8b68-4456-9edf-5af9f129b151 ASAC_257 https://data.aad.gov.au/metadata/records/ASAC_257 http://nla.gov.au/nla.party-617536 Australian Antarctic Data Centre biota oceans ISLANDS EARTH SCIENCE BIOSPHERE TERRESTRIAL ECOSYSTEMS WATER TEMPERATURE OCEAN TEMPERATURE SEALS/SEA LIONS/WALRUSES BIOLOGICAL CLASSIFICATION ANIMALS/VERTEBRATES MAMMALS CARNIVORES SPECIES LIFE HISTORY ECOLOGICAL DYNAMICS SPECIES/POPULATION INTERACTIONS POPULATION DYNAMICS elephant seals time depth recorder tdr diving foraging population FIELD SURVEYS OCEAN > SOUTHERN OCEAN SOUTHERN OCEAN > MACQUARIE ISLAND GEOGRAPHIC REGION > POLAR dataset ftands 2020-01-05T21:16:52Z Metadata record for data from ASAC Project 257 See the link below for public details on this project. From the abstracts of some of the referenced papers: Anatomical and physiological studies of southern elephant seals (Mirounga leonina), particularly in the post-natal period, raise questions of relative musculature growth, control of metabolism, circulation and temperature regulation, which could be important in our understanding of these processes in mammals and of their contribution to adaptation to environmental extremes. The diving behaviour of 14 adult southern elephant seals was investigated using time depth recorders. Each of the seals performed some dives that were longer than its theoretical aerobic dive limit. Forty-four percent of all dives made by post-moult females exceeded the calculated limit compared with 7% of those made by postbreeding females and less than 1% of those made by adult males. The extended dives displayed characteristics that suggested they were predominantly foraging dives, although some were apparently rest dives. Dives longer than the calculated aerobic limits often occurred in bouts; the longest consisted of 63 consecutive dives and lasted 2 days. Postmoult females performed longer bouts of extended dives than postbreeding females. Extended surface periods (longer than 30 min) were not related to the occurrence of extended dives or bouts of extended dives. The possible physiological mechanisms that permit such prolonged continuous dives are discussed. Southern elephant seals may increase the aerobic capacity of dives by lowering their metabolism to approximately 40% of the resting metabolic rate on long dives. There is substantial interseal variability in the methods used to cope with long dives. Some animals appear to use phsyiological strategies that allow them to prolong the time available to them at the bottom of a dive, while others use alternative strategies that may limit the time available at the bottom of their dives. Fourteen time-depth-temperature recorders were recovered from adult southern elephant seals (Mirounga leonina) returning to Macqaurie Island to breed or moult. The resulting temperature/depth profiles indicated that all four males spent most of their time in waters lying over the Antarctic Continental Shelf, whereas only one of the ten females spent any time there. Five of the females foraged just off the Antarctic Continental Shelf, and the other five remained near the Antarctic Polar Front. 1) Mark-resight data were analysed for thirteen cohorts from a declining population of southern elephant seals branded at Macquarie Island between 1951 and 1965. 2) First year survival was essential stable during the 1950s at about 46% for females and 42% for males. There was a dramatic fall in first year survival during the 1960s, declinging to less than 2% for both sexes in 1965. Post-year-1 survival did not change between the 1950s and the 1960s. 3) Comparisons with a stable population of southern elephant seals at South Georgia indicated that both first year and adult survival were lower in the Macquarie Island population. There were no changes in the age at first breeding of the Macquarie Island seals during the study, but this was on average 1 year later than at South Georgia. 4) It is hypothesised that the current decline in elephant seal numbers at several of their major breeding islands is due to the populations returning to pre-sealing levels after they had risen to abnormally high levels with the end of commercial exploitation early this century. 5) Possible tests of the hypothesis include studying the diet and foraging behaviour of southern elephant seals to gain an understanding of the predator-prey relationships, continuing to census the Macquarie Island population to determine if the population levels out at around the estimated pre-sealing levels, and monitoring northern elephant seal populations which were also severely exploited but are currently increasing rapidly. Dataset Antarc* Antarctic Elephant Seal Elephant Seals Macquarie Island Mirounga leonina Southern Elephant Seals Southern Ocean walrus* Research Data Australia (Australian National Data Service - ANDS) Antarctic Southern Ocean The Antarctic ENVELOPE(158.0,159.0,-54.0,-55.0) |