DOI 10.1007/s00227-007-0664-6RESEARCH ARTICLE Trophic relationships of white-chinned petrels from Crozet Islands: combined stomach oil and conventional dietary analyses
aequinoctialis breeding at the Crozet Archipelago (south-ern Indian Ocean) was studied using two complementary methods: lipid analysis of stomach oils as trophic markers together with the conventional dietary approach (i.e., stom-ach content analysis). Objectives were (1) to investigate the adult di...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2007
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.576.3074 http://www.obs-vlfr.fr/LOV/PZPK/pubpdf/Connan_Mar_biol_2007.pdf |
| Summary: | aequinoctialis breeding at the Crozet Archipelago (south-ern Indian Ocean) was studied using two complementary methods: lipid analysis of stomach oils as trophic markers together with the conventional dietary approach (i.e., stom-ach content analysis). Objectives were (1) to investigate the adult diet when they feed for themselves by analyzing stomach oil lipids, and (2) to compare the lipid signature of chick and adult oils. Stomach oils mainly consisted of tria-cylglycerols (TAG), diacylglycerol-ethers (DAGE) and wax esters (WE) (66, 14 and 11%, respectively). The die-tary origin of TAG and WE was evaluated by linear discri-minant analyses with fatty acid and fatty alcohol fractions. Analyses evidenced that stomach oils did not originate from Antarctic krill, but instead from myctophid Wsh, thus demonstrating the importance of mesopelagic Wsh in the nutrition of adult petrels. This result was consistent with the identiWcation of digested remains of myctophids recovered from adult stomach contents after long foraging trips. Large amounts of a rare lipid class, DAGE (up to 76 % of total lip-ids), were identiWed in two stomach oils, together with fresh remains of the squid Gonatus antarcticus (99 % by mass), suggesting that DAGE could have the potential to be trophic markers of cephalopods. Moreover, six oils proba-bly originated from Patagonian toothWsh, thus conWrming strong interactions between white-chinned petrels and Wsh-eries. Comparison between chick and adult stomach oils indicated no major diVerences in their biochemical compo-sition suggesting an identical dietary origin of oils, mainly myctophids. Both adult and chick oils can therefore be used to determine the feeding ecology of adult birds when they feed far away from their breeding grounds. Finally, food analysis of chick samples and adult samples collected after short and long trips indicated diVerent foraging grounds during the two kinds of trips, and also between long trips performed in subtropical and Antarctic waters. |
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