Hello MarMam,

I hope this email finds you well! On behalf of my coauthors, I am excited to 
share our recent publication in Biology Letters titled, "Downsized: gray whales 
using an alternative foraging ground have smaller morphology".

The article is freely available:
https://doi.org/10.1098/rsbl.2023.0043

Abstract

      Describing individual morphology and growth is key for identifying 
ecological niches and monitoring the health and fitness of populations. Eastern 
North Pacific ((ENP), approximately 16,650 individuals) gray whales primarily 
feed in the Arctic/sub-Arctic regions, while a small subgroup called the 
Pacific Coast Feeding Group (PCFG, approximately 212 individuals) instead feeds 
between northern California, USA and British Columbia, Canada. Evidence 
suggests PCFG whales have lower body condition than ENP whales. Here we 
investigate morphological differences (length, skull, and fluke span) and 
compare length-at-age growth curves between ENP and PCFG whales. We use ENP 
gray whale length-at-age data comprised of strandings, whaling, and aerial 
photogrammetry (1926–1997) for comparison to data from PCFG whales collected 
through non-invasive techniques (2016–2022) to estimate age (photo 
identification) and length (drone-based photogrammetry). We use Bayesian 
methods to incorporate uncertainty associated with morphological measurements 
(manual and photogrammetric) and age estimates. We find that while PCFG and ENP 
whales have similar growth rates, PCFG whales reach smaller asymptotic lengths. 
Additionally, PCFG whales have relatively smaller skulls and flukes than ENP 
whales. These findings represent a striking example of morphological adaptation 
that may facilitate PCFG whales accessing a foraging niche distinct from the 
Arctic foraging grounds of the broader ENP population.


Bierlich, K. C., Kane, A., Hildebrand, L., Bird, C. N., Fernandez Ajo, A., 
Stewart, J. D., Hewitt, J., Hildebrand, I., Sumich, J., & Torres, L. G. (2023). 
Downsized: gray whales using an alternative foraging ground have smaller 
morphology. Biology Letters, 19(8).
https://doi.org/10.1098/rsbl.2023.0043


All the best,
KC


KC (Kevin) Bierlich, PhD, MEM

Postdoctoral Scholar

Geospatial Ecology of Marine Megafauna 
(GEMM<https://mmi.oregonstate.edu/gemm-lab>) Lab

Marine Mammal Institute | Dept. of Fisheries, Wildlife, & Conservation Sciences

Oregon State University

Pronouns: he, him, his

kevin.bierl...@oregonstate.edu<mailto:kevin.bierl...@oregonstate.edu>

https://kcbierlich.wixsite.com/kcbierlich








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