[MARMAM] New Publication on gray seal isotopic niches

Keith Hernandez keith.hernandez2011 at gmail.com
Thu Jun 10 09:13:30 PDT 2021

Hello MARMAM community,

On behalf of my coauthors, I am excited to share our latest publication in
*Marine** Ecology Progress Series*.

Keith M. Hernandez, Wendy Blay Puryear, Jonathan A. Runstadler, Michael J.
Polito (2021) Little interannual variability in gray seal (*Halichoerus
grypus*) trophic niches during pregnancy despite variable environmental
conditions. Marine Ecology Progress Series 667: 207-217. DOI:

ABSTRACT: The successful recruitment of juveniles into a population is
often dependent on receiving sufficient nutrition pre- and
post-parturition. Thus, variation in maternal foraging ecology during
pregnancy, whether due to prey choice, prey availability or fluctuations in
environmental conditions, can impact offspring fitness in the subsequent
breeding season. As many pinnipeds spend the majority of the gestation
period at sea, past studies have used the biogeochemical analysis of pup
tissues to infer female diets during this critical period. The objective of
our study was to examine the trophic niches of a population of pregnant
female gray seals *Halichoerus grypus* over a 4 yr period in coastal
Massachusetts, USA by analyzing the stable carbon (δ13C) and nitrogen (δ15N)
values of pup lanugo. In addition, we sought to determine if individual and
inter-annual variation in pup body condition could be explained by
differences in female trophic niches, prey availability, or environmental
conditions. Stable isotope-based metrics of trophic niche position, width,
and overlap indicated little to no interannual variability in female
foraging ecology at the population level despite variation in environmental
conditions and prey availability in the fall on Georges Bank. Model
selection indicated a positive relationship between pup body condition and δ
13C values, which is indicative of pregnant females foraging on benthic,
demersal, or nearshore prey species during the fall prior to parturition.
This indicates that individual variation in female foraging ecology during
pregnancy has a carry-over effect on offspring condition with possible
implications for first-year survival, and ultimately recruitment to the
adult population.

The article can be found at the link here
<https://www.int-res.com/abstracts/meps/v667/p207-217/>, or you can reach
me at keith.hernandez2011 at gmail.com for a PDF copy or with any questions or

Keith M. Hernandez, PhD | he/him/his
Postdoctoral Scholar-Employee
Ecology and Evolutionary Biology Department/Institute of Marine Sciences
University of California Santa Cruz
Santa Cruz, CA
Google Scholar
ResearchGate <https://www.researchgate.net/profile/Keith_Hernandez2>
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