TY - JOUR
T1 - Estimating blue whale skin isotopic incorporation rates and baleen growth rates
T2 - Implications for assessing diet and movement patterns in mysticetes
AU - Busquets-Vass, Geraldine
AU - Newsome, Seth D.
AU - Calambokidis, John
AU - Serra-Valente, Gabriela
AU - Jacobsen, Jeff K.
AU - Aguíñiga-García, Sergio
AU - Gendron, Diane
N1 - Funding Information:
We would like to thank the institutions that facilitated the use of tissues samples and issued the permits to collect and process these samples: NOAA-SWFSC, CRC, CICIMAR-IPN, HSU-Vertebrate Museum, Museo de la Ballena y Ciencias del Mar (La Paz, BCS), the California Department of Parks and Recreation-Prairie Creek Redwoods State Park, NOAA/NMFS and SEMARNAT. We are also very grateful to all the personnel from the former institutions, the Stranding Network of California, and the Center for Stable Isotopes of the University of New Mexico who participated in the collection and processing of the tissue samples. We would also like to thank the John H. Prescott Marine Mammal Rescue Assistance Grant Program that has provided grants to the stranding networks. J. Rice, J. Loomis, T. Holmes, and F.J. Gómez-Díaz collaborated during the process of locating potential baleen plates for this study and we are very beholden for their support. We would also like to give special recognition to K. Robertson who helped with the logistics of sample selection and the sex identification of an important baleen sample at the genetics lab in SWFSC. M.A. Pardo, H. Villalobos-Ortiz, C. Arnold, and two anonymous reviewers made some valuable comments to improve the manuscript.
PY - 2017/5
Y1 - 2017/5
N2 - Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions. Nitrogen (δ15N) and carbon (δ13C) isotope values of blue whale skin and potential prey were analyzed from three foraging zones (Gulf of California, California Current System, and Costa Rica Dome) in the northeast Pacific from 1996-2015. We also measured δ15N and δ13C values along the lengths of baleen plates collected from six blue whales stranded in the 1980s and 2000s. Skin was separated into three strata: basale, externum, and sloughed skin. A mean (-SD) skin isotopic incorporation rate of 163-91 days was estimated by fitting a generalized additive model of the seasonal trend in δ15N values of skin strata collected in the Gulf of California and the California Current System. A mean (-SD) baleen growth rate of 15.5-2.2 cm y-1 was estimated by using seasonal oscillations in δ15N values from three whales. These oscillations also showed that individual whales have a high fidelity to distinct foraging zones in the northeast Pacific across years. The absence of oscillations in δ15N values of baleen sub-samples from three male whales suggests these individuals remained within a specific zone for several years prior to death. δ13C values of both whale tissues (skin and baleen) and potential prey were not distinct among foraging zones. Our results highlight the importance of considering tissue isotopic incorporation and growth rates when studying migratory mysticetes and provide new insights into the individual movement strategies of blue whales.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
AB - Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions. Nitrogen (δ15N) and carbon (δ13C) isotope values of blue whale skin and potential prey were analyzed from three foraging zones (Gulf of California, California Current System, and Costa Rica Dome) in the northeast Pacific from 1996-2015. We also measured δ15N and δ13C values along the lengths of baleen plates collected from six blue whales stranded in the 1980s and 2000s. Skin was separated into three strata: basale, externum, and sloughed skin. A mean (-SD) skin isotopic incorporation rate of 163-91 days was estimated by fitting a generalized additive model of the seasonal trend in δ15N values of skin strata collected in the Gulf of California and the California Current System. A mean (-SD) baleen growth rate of 15.5-2.2 cm y-1 was estimated by using seasonal oscillations in δ15N values from three whales. These oscillations also showed that individual whales have a high fidelity to distinct foraging zones in the northeast Pacific across years. The absence of oscillations in δ15N values of baleen sub-samples from three male whales suggests these individuals remained within a specific zone for several years prior to death. δ13C values of both whale tissues (skin and baleen) and potential prey were not distinct among foraging zones. Our results highlight the importance of considering tissue isotopic incorporation and growth rates when studying migratory mysticetes and provide new insights into the individual movement strategies of blue whales.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
UR - http://www.scopus.com/inward/record.url?scp=85020029063&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0177880
DO - 10.1371/journal.pone.0177880
M3 - Artículo
C2 - 28562625
SN - 1932-6203
VL - 12
JO - PLoS ONE
JF - PLoS ONE
IS - 5
M1 - e0177880
ER -