Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem.
The leopard seal, Hydrurga leptonyx, is an apex predator that has a key role as consumer within the Antarctic ecosystem. Due to the constraints of traditional methods for studying feeding ecology fatty acids (FAs) analysis of blubber has become a useful tool for determining diet since it provides an...
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ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_45987 2024-05-12T07:55:34+00:00 Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. Guerrero, AI Negrete, J Marquez, M Menucci, J Zaman, K Rogers, TL 2014-08-22 http://hdl.handle.net/1959.4/unsworks_45987 https://doi.org/10.13140/rg.2.2.14297.52321 unknown http://purl.org/au-research/grants/arc/LP0989933 http://hdl.handle.net/1959.4/unsworks_45987 https://doi.org/10.13140/rg.2.2.14297.52321 metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ XXXIII Scientific Committee on Antarctic Research (SCAR) Open Science Conference, Auckland, New Zealand, 2014-08-22 - 2014-09-02 conference presentation http://purl.org/coar/resource_type/R60J-J5BD 2014 ftunswworks https://doi.org/10.13140/rg.2.2.14297.52321 2024-04-17T15:55:34Z The leopard seal, Hydrurga leptonyx, is an apex predator that has a key role as consumer within the Antarctic ecosystem. Due to the constraints of traditional methods for studying feeding ecology fatty acids (FAs) analysis of blubber has become a useful tool for determining diet since it provides an indication of long-term dietary histories. FAs however, are not distributed uniformly within the blubber so understanding the degree of stratification is important in order to obtain accurate results. The FA stratification in blubber has not been examined for the leopard seal. We used whole blubber core samples from 24 individual leopard seals captured in the Danco Coast region off the Western Antarctic Peninsula (WAP). The cores were sub-sectioned into: outer, middle and inner layers and the FA compositions were compared with potential prey species (krill, fish and penguins). We found 17 FAs present at greater than trace amounts (>0.5%) across all samples. The most abundant FAs were: C18:1ω9, C16:1, C22:6ω3, C16:0 and C18:1ω7 which accounted for approximately 70% of the total. This composition of blubber is similar to other marine mammals, although some differences do exist. Principal Component Analysis confirmed clear separation between inner and outer layers where most of the FAs were present in significantly different amounts between these layers. Monounsaturated FAs (MUFA) dominated the three layers being more abundant in the outer layer. The higher presence of MUFAs, which have comparatively low melting points, in the outer layer, may suggest that this section has a thermoregulatory function. On the other hand, polyunsaturated (PUFA) and saturated FAs (SFA) were more abundant in the inner layer. PUFAs are known to be of dietary origin and SFAs are inert chemically so they can be used as long-term reserve suggesting this layer is associated with dietary intake. Moreover, the FA composition of the inner blubber layer resembles those of the prey more closely than the outer layer. Detailed analysis of the inner ... Conference Object Antarc* Antarctic Antarctic Peninsula Hydrurga leptonyx Leopard Seal Leopard Seals UNSW Sydney (The University of New South Wales): UNSWorks Antarctic The Antarctic Antarctic Peninsula Hydrurga ENVELOPE(-61.626,-61.626,-64.145,-64.145) Danco ENVELOPE(-61.033,-61.033,-64.717,-64.717) Danco Coast ENVELOPE(-62.000,-62.000,-64.700,-64.700) |
institution |
Open Polar |
collection |
UNSW Sydney (The University of New South Wales): UNSWorks |
op_collection_id |
ftunswworks |
language |
unknown |
description |
The leopard seal, Hydrurga leptonyx, is an apex predator that has a key role as consumer within the Antarctic ecosystem. Due to the constraints of traditional methods for studying feeding ecology fatty acids (FAs) analysis of blubber has become a useful tool for determining diet since it provides an indication of long-term dietary histories. FAs however, are not distributed uniformly within the blubber so understanding the degree of stratification is important in order to obtain accurate results. The FA stratification in blubber has not been examined for the leopard seal. We used whole blubber core samples from 24 individual leopard seals captured in the Danco Coast region off the Western Antarctic Peninsula (WAP). The cores were sub-sectioned into: outer, middle and inner layers and the FA compositions were compared with potential prey species (krill, fish and penguins). We found 17 FAs present at greater than trace amounts (>0.5%) across all samples. The most abundant FAs were: C18:1ω9, C16:1, C22:6ω3, C16:0 and C18:1ω7 which accounted for approximately 70% of the total. This composition of blubber is similar to other marine mammals, although some differences do exist. Principal Component Analysis confirmed clear separation between inner and outer layers where most of the FAs were present in significantly different amounts between these layers. Monounsaturated FAs (MUFA) dominated the three layers being more abundant in the outer layer. The higher presence of MUFAs, which have comparatively low melting points, in the outer layer, may suggest that this section has a thermoregulatory function. On the other hand, polyunsaturated (PUFA) and saturated FAs (SFA) were more abundant in the inner layer. PUFAs are known to be of dietary origin and SFAs are inert chemically so they can be used as long-term reserve suggesting this layer is associated with dietary intake. Moreover, the FA composition of the inner blubber layer resembles those of the prey more closely than the outer layer. Detailed analysis of the inner ... |
format |
Conference Object |
author |
Guerrero, AI Negrete, J Marquez, M Menucci, J Zaman, K Rogers, TL |
spellingShingle |
Guerrero, AI Negrete, J Marquez, M Menucci, J Zaman, K Rogers, TL Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
author_facet |
Guerrero, AI Negrete, J Marquez, M Menucci, J Zaman, K Rogers, TL |
author_sort |
Guerrero, AI |
title |
Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
title_short |
Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
title_full |
Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
title_fullStr |
Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
title_full_unstemmed |
Fatty acid composition suggests leopard seals are no longer apex predators in the WAP ecosystem. |
title_sort |
fatty acid composition suggests leopard seals are no longer apex predators in the wap ecosystem. |
publishDate |
2014 |
url |
http://hdl.handle.net/1959.4/unsworks_45987 https://doi.org/10.13140/rg.2.2.14297.52321 |
long_lat |
ENVELOPE(-61.626,-61.626,-64.145,-64.145) ENVELOPE(-61.033,-61.033,-64.717,-64.717) ENVELOPE(-62.000,-62.000,-64.700,-64.700) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Hydrurga Danco Danco Coast |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Hydrurga Danco Danco Coast |
genre |
Antarc* Antarctic Antarctic Peninsula Hydrurga leptonyx Leopard Seal Leopard Seals |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Hydrurga leptonyx Leopard Seal Leopard Seals |
op_source |
XXXIII Scientific Committee on Antarctic Research (SCAR) Open Science Conference, Auckland, New Zealand, 2014-08-22 - 2014-09-02 |
op_relation |
http://purl.org/au-research/grants/arc/LP0989933 http://hdl.handle.net/1959.4/unsworks_45987 https://doi.org/10.13140/rg.2.2.14297.52321 |
op_rights |
metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.13140/rg.2.2.14297.52321 |
_version_ |
1798835379926728704 |