The influence of biopsy site and pregnancy on stable isotope ratios in humpback whale skin
- PMID: 38576213
- DOI: 10.1002/rcm.9746
The influence of biopsy site and pregnancy on stable isotope ratios in humpback whale skin
Abstract
Rationale: Stable isotope analysis (SIA) of free-swimming mysticetes using biopsies is often limited in sample size and uses only one sample per individual, failing to capture both intra-individual variability and the influence of demographic and physiological factors on isotope ratios.
Methods: We applied SIA of δ13C and δ15N to humpback whale (Megaptera novaeangliae) biopsies taken during the foraging season along the western Antarctic Peninsula to quantify intra-individual variation from repeatedly sampled individuals, as well as to determine the effect of biopsy collection site, sex, and pregnancy on isotope ratios.
Results: There was substantial variability in δ13C from multiple biopsies taken from the same individuals, though δ15N was much more consistent. Side of the body (left versus right) and biopsy location (dorsal, anterior, ventral, and posterior) did marginally affect the isotopic composition of δ15N but not δ13C. Pregnancy had a significant effect on both δ13C and δ15N, where pregnant females were depleted in both when compared to non-pregnant females and males.
Conclusions: These results indicate that isotopic signatures are influenced by multiple endogenous and exogenous factors and emphasize value in accounting for intra-individual variability and pregnancy status within a sampled population. Placed within an ecological context, the endogenous variability in δ13C observed here may be informative for future isotopic analyses.
© 2024 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
References
REFERENCES
-
- Engel MH, Fagundes NJR, Rosenbaum HC, et al. Mitochondrial DNA diversity of the southwestern Atlantic humpback whale (Megaptera novaeangliae) breeding area off Brazil, and the potential connections to Antarctic feeding areas. Conserv Genet. 2008;9(5):1253‐1262. doi:10.1007/s10592‐007‐9453‐5
-
- Pallin LJ, Baker CS, Steel D, et al. High pregnancy rates in humpback whales (Megaptera novaeangliae) around the Western Antarctic Peninsula, evidence of a rapidly growing population. R Soc Open Sci. 2018;5(5):180017. doi:10.1098/rsos.180017
-
- Bengtson Nash SM, Castrillon J, Eisenmann P, et al. Signals from the south: Humpback whales carry messages of Antarctic sea‐ice ecosystem variability. Glob Chang Biol. 2017;24(4):1500‐1510.
-
- Schall E, Thomisch K, Boebel O, Gerlach G, Spiesecke S, Van Opzeeland I. Large‐scale spatial variabilities in the humpback whale acoustic presence in the Atlantic sector of the Southern Ocean. R Soc Open Sci. 2020;7(12):201347. doi:10.1098/rsos.201347
-
- Schall E, Thomisch K, Boebel O, et al. Multi‐year presence of humpback whales in the Atlantic sector of the Southern Ocean but not during El Niño. Commun Biol. 2021;4(1):790. doi:10.1038/s42003‐021‐02332‐6