[MARMAM] New paper on California sea lion stress and immune markers

Geno DeRango gderango at gmail.com
Mon May 27 04:42:26 PDT 2019


Dear MARMAM,

My co-authors and I are happy to present the new publication:

Eugene J DeRango, Katherine C Prager, Denise J Greig, Amanda W Hooper,
Daniel E Crocker, Climate variability and life history impact stress,
thyroid, and immune markers in California sea lions (*Zalophus
californianus*) during El Niño conditions, *Conservation Physiology*,
Volume 7, Issue 1, 2019, coz01.

The PDF can be downloaded here open-access:
https://doi.org/10.1093/conphys/coz010

Abstract: Wildlife is exposed to a diverse set of extrinsic and intrinsic
stressors, such as climatic variation or life history constraints, which
may impact individual health and fitness. El Niño and climatic anomalies
between 2013 and 2016 had major ecological impacts on the California
Current ecosystem. As top marine predators, California sea lions (CSL)
experienced decreased prey availability and foraging success, impacting
their nutritional state. We hypothesize that chronic stress to juvenile CSL
increased during the 2015–2016 El Niño and that breeding represents a
period of chronic stress for adults, which impact a variety of
physiological processes. We opportunistically captured and sampled juvenile
CSL (female, *n =* 29; male, *n =* 38) in central California and adult male
CSL (*n =* 76) in Astoria, Oregon and quantified a suite of analytes in
serum as indicators of acute stress markers, metabolism and thyroid
function, and adaptive immune response. We found that stress hormones and
glucose were decreased in juvenile CSL during 2016 relative to 2015 and in
adult male CSL after the breeding season, which may indicate chronic stress
downregulating HPA (hypothalamic-pituitary-adrenal) axis sensitivity with
associated metabolic impacts. Conversely, thyroid hormones for both
juvenile and adult male CSL were increased, suggesting greater energetic
requirements resulting from increased foraging activity during suboptimal
conditions in juveniles and breeding tenure in adult males. Immunoglobulin
IgG was elevated in juveniles in 2016 but reduced in adult males
post-breeding. This suggests that juveniles may face immunostimulatory
pressure during anomalously warm ocean environments; however, for adult
males, breeding is a significant energetic cost resulting in reductions to
immune function. Our results indicate that environmental conditions and
life history stage may influence physiological responses in an important
marine predator and a sentinel species of changing ocean ecosystems.

Please do not hesitate to contact me with questions at gderango at gmail.com .

Best regards,
Geno DeRango

_____________
PhD Student
Bielefeld University
Galapagos sea lion Project
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