Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 523:243-253 (2015) - DOI: https://doi.org/10.3354/meps11176 Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures Roxanne S. Beltran1,4,*, Megan Connolly Sadou2, Richard Condit3, Sarah H. Peterson1, Colleen Reichmuth2, Daniel P. Costa1 1Department of Ecology & Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA 2Institute of Marine Sciences, Long Marine Laboratory, Santa Cruz, CA 95060, USA 3Smithsonian Tropical Research Institute, Balboa, Panama City, 0843-03092, Panama 4Present address: Department of Biological Sciences, University of Alaska, Anchorage, AK 99508, USA *Corresponding author: roxanne.beltran@gmail.com ABSTRACT: Stable isotope analysis of slow-growing, metabolically inert tissues is a common method for investigating foraging ecology in migratory animals, as direct observations of feeding are often not possible. Using tissue growth dynamics to interpret foraging timelines can maximize the utility of foraging data; however, applying inappropriate growth models is problematic, and high-resolution growth measurements are seldom made. We used photogrammetry to repeatedly measure the length of whiskers in 93 follicles over 670 d in a trained, captive northern elephant seal Mirounga angustirostris. We developed and optimized a follicle-specific growth model to describe the 18000 whisker length measurements. Whiskers from the captive seal exhibited asymptotic growth that was described by the von Bertalanffy growth function. Applying the growth model to serially sampled whiskers from 4 free-ranging adult female northern elephant seals resulted in alignment of peaks in δ15N along the length of whiskers with the breeding haul-out period, when seals are not feeding. Our study provides a high-resolution whisker growth model and is the first to use whisker growth dynamics to improve temporal interpretation of isotopic ratios. KEY WORDS: Vibrissae · Whisker · Asymptotic growth rate · Stable isotope · Seal Full text in pdf format PreviousNextCite this article as: Beltran RS, Connolly Sadou M, Condit R, Peterson S, Reichmuth C, Costa DP (2015) Fine-scale whisker growth measurements can reveal temporal foraging patterns from stable isotope signatures. Mar Ecol Prog Ser 523:243-253. https://doi.org/10.3354/meps11176 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 523. Online publication date: March 16, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.