TY - JOUR
T1 - Stable Isotope Values in South American Fur Seal Pup Whiskers as Proxies of Year-round Maternal Foraging Ecology
AU - Jones, Kayleigh A.
AU - Baylis, Alastair M. M.
AU - Orben, Rachael A.
AU - Ratcliffe, Norman
AU - Votier, Stephen C.
AU - Newton, Jason
AU - Staniland, Iain J.
N1 - Funding Information:
This project was led by the South Atlantic Environmental Research Institute (SAERI) and British Antarctic Survey (BAS). The authors gratefully acknowledge funding from the National Geographic Society (Early Career Explorers Grant), the NERC Life Sciences Mass Spectrometry Facility and the NERC Great Western Four+ Doctoral Training Partnership. They sincerely thank the Falkland Islands Government Fisheries Department, who provided assistance accessing the Bird Island field site. They also thank Dr Rona McGill for her support while running whisker samples through the Isotope Ratio Mass Spectrometer at the Scottish Universities Environmental Research Centre. They additionally thank Dr Kimberley Bennett, Dr Robbie McDonald and two anonymous reviewers for providing valuable feedback on this manuscript.
Funding Information:
This study was funded by the National Geographic Society (Early Career Explorers Grant; WW-260ER-17), the NERC Life Sciences Mass Spectrometry Facility (EK280-03/17) and the NERC Great Western Four + Doctoral Training Partnership (GW4 + DTP, NE/L002434/1). Acknowledgements
Funding Information:
This project was led by the South Atlantic Environmental Research Institute (SAERI) and British Antarctic Survey (BAS). The authors gratefully acknowledge funding from the National Geographic Society (Early Career Explorers Grant), the NERC Life Sciences Mass Spectrometry Facility and the NERC Great Western Four+ Doctoral Training Partnership. They sincerely thank the Falkland Islands Government Fisheries Department, who provided assistance accessing the Bird Island field site. They also thank Dr Rona McGill for her support while running whisker samples through the Isotope Ratio Mass Spectrometer at the Scottish Universities Environmental Research Centre. They additionally thank Dr Kimberley Bennett, Dr Robbie McDonald and two anonymous reviewers for providing valuable feedback on this manuscript.
Publisher Copyright:
© 2020, The Author(s).
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Natural selection should favour strategies that maximise reproductive success. Females may use different resources during progressive stages of reproduction according to energetic demands, behavioural constraints and prey availability. We used South American fur seal, Arctocephalus australis australis, pup whisker isotope values as proxies for maternal diet and habitat use to determine how resource use (1) changes throughout pup development from in utero growth to mid-end of lactation and (2) how it differs among individuals. The longest whisker was cut from 5 male and 5 female fur seal pups (of approximately 8 months of age) at Bird Island, Falkland Islands, in 2018, and δ15N values and δ13C values were analysed every 5 mm along the length of each whisker. Patterns in δ13C values indicated that mothers used different habitats during the annual cycle, likely coinciding with seasonal shifts in prey availability or distribution. The individual specialisation index based on δ13C values was 0.34, indicating that adult females used different habitats, which could reduce intra-specific competition and ultimately enhance pup growth and survival. An increase in δ15N values occurred along every pup whisker from pup birth to mid-end of lactation, which likely reflected trophic enrichment related to suckling and fasting by pups, overriding the maternal isotopic signature. Pup whisker stable isotopes are useful proxies of maternal foraging ecology. However, physiological processes complicate interpretations by altering δ15N values. Interpreting these values therefore requires additional knowledge of the species’ ecology and physiology.
AB - Natural selection should favour strategies that maximise reproductive success. Females may use different resources during progressive stages of reproduction according to energetic demands, behavioural constraints and prey availability. We used South American fur seal, Arctocephalus australis australis, pup whisker isotope values as proxies for maternal diet and habitat use to determine how resource use (1) changes throughout pup development from in utero growth to mid-end of lactation and (2) how it differs among individuals. The longest whisker was cut from 5 male and 5 female fur seal pups (of approximately 8 months of age) at Bird Island, Falkland Islands, in 2018, and δ15N values and δ13C values were analysed every 5 mm along the length of each whisker. Patterns in δ13C values indicated that mothers used different habitats during the annual cycle, likely coinciding with seasonal shifts in prey availability or distribution. The individual specialisation index based on δ13C values was 0.34, indicating that adult females used different habitats, which could reduce intra-specific competition and ultimately enhance pup growth and survival. An increase in δ15N values occurred along every pup whisker from pup birth to mid-end of lactation, which likely reflected trophic enrichment related to suckling and fasting by pups, overriding the maternal isotopic signature. Pup whisker stable isotopes are useful proxies of maternal foraging ecology. However, physiological processes complicate interpretations by altering δ15N values. Interpreting these values therefore requires additional knowledge of the species’ ecology and physiology.
UR - http://www.scopus.com/inward/record.url?scp=85091717901&partnerID=8YFLogxK
U2 - 10.1007/s00227-020-03760-4
DO - 10.1007/s00227-020-03760-4
M3 - Article
AN - SCOPUS:85091717901
SN - 0025-3162
VL - 167
JO - Marine Biology
JF - Marine Biology
M1 - 148
ER -