TY - JOUR
T1 - Use of 15 N-enriched glycine to estimate vibrissa growth in free-ranging northern elephant seals Mirounga angustirostris
AU - Aurioles-Gamboa, David
AU - Newsome, Seth D.
AU - Hassrick, Jason L.
AU - Acosta-Pachón, Tatiana
AU - Aurioles-Rodríguez, Félix
AU - Costa, Daniel P.
N1 - Publisher Copyright:
© Inter-Research 2019 ·
PY - 2019/4/4
Y1 - 2019/4/4
N2 - The stable isotope composition of continuously growing but metabolically inert tissues remains unaltered after they are synthesized, providing insights on seasonal and inter-annual variation in the ecology of individuals. In pinnipeds, isotope analysis of sub-sampled vibrissae can provide a longitudinal record of movement, diet, and even physiological state at the individual level. To reliably apply this approach, however, taxon-specific vibrissa growth needs to be estimated, especially for species with complicated annual life cycles that undergo periods of active foraging interspersed with reproduction and/or molting associated with fasting. Here, we intravenously injected 15 N-enriched glycine to estimate vibrissa growth in 8 free-ranging adult female northern elephant seals during their (shorter) post-breeding and (longer) post-molting foraging trips; all animals were instrumented with satellite tags to track movements and vibrissae were collected when the animals returned to land. We found a significant positive relationship between the maximum δ 15 N values, representing 15 N-glycine injections, and the distance between the origin of the spike and the root of the vibrissa. The δ 15 N spikes that occurred closest to the root were narrower and had lower δ 15 N values than those that occurred closer to the tip of the vibrissa, suggesting differential velocities of 15 N-glycine absorption and vibrissa growth. A derived von Bertalanffy model yielded mean (±SD) growth of 0.015 ± 0.006 d −1 , similar to that previously reported for a single captive northern elephant seal. Vibrissa length is an important consideration for accurately interpreting isotope-based ecological and physiological histories given the non-continuous growth observed in our study.
AB - The stable isotope composition of continuously growing but metabolically inert tissues remains unaltered after they are synthesized, providing insights on seasonal and inter-annual variation in the ecology of individuals. In pinnipeds, isotope analysis of sub-sampled vibrissae can provide a longitudinal record of movement, diet, and even physiological state at the individual level. To reliably apply this approach, however, taxon-specific vibrissa growth needs to be estimated, especially for species with complicated annual life cycles that undergo periods of active foraging interspersed with reproduction and/or molting associated with fasting. Here, we intravenously injected 15 N-enriched glycine to estimate vibrissa growth in 8 free-ranging adult female northern elephant seals during their (shorter) post-breeding and (longer) post-molting foraging trips; all animals were instrumented with satellite tags to track movements and vibrissae were collected when the animals returned to land. We found a significant positive relationship between the maximum δ 15 N values, representing 15 N-glycine injections, and the distance between the origin of the spike and the root of the vibrissa. The δ 15 N spikes that occurred closest to the root were narrower and had lower δ 15 N values than those that occurred closer to the tip of the vibrissa, suggesting differential velocities of 15 N-glycine absorption and vibrissa growth. A derived von Bertalanffy model yielded mean (±SD) growth of 0.015 ± 0.006 d −1 , similar to that previously reported for a single captive northern elephant seal. Vibrissa length is an important consideration for accurately interpreting isotope-based ecological and physiological histories given the non-continuous growth observed in our study.
KW - N-enriched glycine
KW - Northern elephant seal
KW - Vibrissae growth
UR - http://www.scopus.com/inward/record.url?scp=85063804502&partnerID=8YFLogxK
U2 - 10.3354/meps12913
DO - 10.3354/meps12913
M3 - Artículo
AN - SCOPUS:85063804502
SN - 0171-8630
VL - 614
SP - 199
EP - 207
JO - Marine Ecology Progress Series
JF - Marine Ecology Progress Series
ER -