Decadal changes in blood delta C-13 values, at-sea distribution, and weaning mass of southern elephant seals from Kerguelen Islands
|Author(s)||Mestre Julie1, 2, Authier Matthieu3, 4, 5, Cherel Yves1, Harcourt Rob6, McMahon Clive R.6, 7, 8, Hindell Mark A.8, Charrassin Jean-Benoit9, Guinet Christophe1|
|Affiliation(s)||1 : La Rochelle Univ, Ctr Etud Biol Chize CEBC, UMR 7372, CNRS, F-79360 Villiers En Bois, France.
2 : Sorbonne Univ, Coll Doctoral, F-75005 Paris, France.
3 : La Rochelle Univ, UMS 3462, Observ PELAGIS, La Rochelle, France.
4 : CNRS, La Rochelle, France.
5 : ADERA, Pessac, France.
6 : Macquarie Univ, Dept Biol Sci, N Ryde, NSW, Australia.
7 : Sydney Inst Marine Sci, IMOS Anim Tagging, Sydney, NSW, Australia.
8 : Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas, Australia.
9 : Sorbonne Univ, LOCEAN IPSL, UMR 7159 Paris, CNRS,IRD,MNHN, Paris, France.
|Source||Proceedings Of The Royal Society B-biological Sciences (0962-8452) (Royal Soc), 2020-08 , Vol. 287 , N. 1933 , P. 20201544 (10p.)|
|WOS© Times Cited||6|
|Keyword(s)||foraging habitat, stable isotopes, bio-logging, population strategies, decadal change, Indian sector of the Southern Ocean|
Changes in the foraging environment and at-sea distribution of southern elephant seals from Kerguelen Islands were investigated over a decade (2004-2018) using tracking, weaning mass, and blood delta C-13 values. Females showed either a sub-Antarctic or an Antarctic foraging strategy, and no significant shift in their at-sea distribution was detected between 2004 and 2017. The proportion of females foraging in sub-Antarctic versus Antarctic habitats did not change over the 2006-2018 period. Pup weaning mass varied according to the foraging habitat of their mothers. The weaning mass of sub-Antarctic foraging mothers' pups decreased by 11.7 kg over the study period, but they were on average 5.8 kg heavier than pups from Antarctic foraging mothers. Pup blood delta C-13 values decreased by 1.1 parts per thousand over the study period regardless of their sex and the presumed foraging habitat of their mothers. Together, these results suggest an ecological change is occurring within the Indian sector of the Southern Ocean with possible consequences on the foraging performance of southern elephant seals. We hypothesize that this shift in delta C-13 is related to a change in primary production and/or in the composition of phytoplankton communities, but this requires further multidisciplinary investigations.