Trophic relationships of white-chinned petrels from Crozet Islands: combined stomach oil and conventional dietary analyses |
| |
Authors: | Maëlle Connan Yves Cherel Géraldine Mabille Patrick Mayzaud |
| |
Institution: | (1) Université Pierre et Marie Curie-Paris 6 et CNRS, Observatoire Océanologique, Océanographie Biochimique et Ecologie, UMR 7093, LOV, BP 28, 06234 Villefranche-sur-mer, France;(2) CNRS, UPR 1934, Centre d’Etudes Biologiques de Chizé, BP 14, 79360 Villiers-en-Bois, France |
| |
Abstract: | The diet of white-chinned petrels Procellaria aequinoctialis breeding at the Crozet Archipelago (southern Indian Ocean) was studied using two complementary methods: lipid analysis of
stomach oils as trophic markers together with the conventional dietary approach (i.e., stomach 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 triacylglycerols (TAG), diacylglycerol-ethers (DAGE)
and wax esters (WE) (66, 14 and 11%, respectively). The dietary origin of TAG and WE was evaluated by linear discriminant
analyses with fatty acid and fatty alcohol fractions. Analyses evidenced that stomach oils did not originate from Antarctic
krill, but instead from myctophid fish, thus demonstrating the importance of mesopelagic fish in the nutrition of adult petrels.
This result was consistent with the identification 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 lipids), were identified 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 probably
originated from Patagonian toothfish, thus confirming strong interactions between white-chinned petrels and fisheries. Comparison
between chick and adult stomach oils indicated no major differences in their biochemical composition 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 different foraging grounds during the two kinds of trips, and also between
long trips performed in subtropical and Antarctic waters. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|