[MARMAM] New publication: gestation and lactation influence stable isotope composition of epidermis layers

Michelle Gelippi mgelippi at pg.cibnor.mx
Mon Nov 2 14:15:22 PST 2020

Dear all,

We are very excited to inform the outcomes of our latest investigation on
the effects of gestation and lactation periods on the stable isotope
composition of epidermis layers of free ranging gray whales are now
presented and available Open Access in PLOS ONE.

“*Tracing gestation and lactation in free ranging gray whales using the
stable isotopic composition of epidermis layers"*


"The isotopic composition of baleen whales’ epidermis structural layers can
give information about dietary change over time. This study investigated if
epidermis layers integrated isotopic values that record physiological
changes from gestation to lactation. Epidermis tissues (n = 43) were
collected from free ranging lactating female gray whale and calves during
the beginning of three breeding seasons. Modelling of δ13C and δ15N values
show intra- and inter-individual differences based on epidermal layers, age
class and year of sampling. The isotopic composition of mother-calf pairs
is correlated, and the estimates of the maximum mother-to-calf isotopic
difference was ~1.4‰ for δ13C and between 1 and 1.5‰ for δ15N values.
Change in δ15N values among epidermal layers in calves was associated with
the transition from fetus to consumption of maternal milk. It is here
proposed when lactation influences calf epidermis, δ15N values decrease
consistently from the outermost to the innermost layer. However, if a calf
was born only few days before collection, epidermis integrates more
variable δ15N patterns because gestation still affects the isotopic
composition of the layers. The possibility of calculating mother-to-calf
nitrogen isotope fractionation, and the regularity of changes between calf
layer δ15N values, allowed results of an isotopic clock model to predict
the age of each calf when sampled with its mother. This model has the
potential to be a straightforward method to estimate the beginning of
lactation, therefore calf birth date when direct observations are not
feasible. The non-lethal remote collection of epidermis appears to be an
effective tool for the study of the physiology of reproduction of baleen
whales. The parallel study of the three epidermal structural layers
highlighted the importance of considering the unique mother-calf pair
physiological status at the time of sampling time when stable isotope
results are interpreted."


DOI: https://doi.org/10.1371/journal.pone.0240171

All the best,


Michelle Gelippi
PhD fellow
Centro De Investigación Biológicas del Noreste (CIBNOR)
La Paz, BCS, Mexico
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