[MARMAM] New Publication: Blubber endocrine profiles provide insights into reproductive biology in blue whales from the eastern North Pacific Ocean (Valentina Melica)

Valentina Melica valentinamelica88 at gmail.com
Thu Jun 17 08:15:27 PDT 2021

My co-authors and I are pleased to announce the publication of a new
manuscript in General and Comparative Endocrinology:

Melica, V., Atkinson, S., Gendron, D., Calambokidis, J., Mueter, F., 2021.
Blubber endocrine profiles provide insights into reproductive biology in
blue whales from the eastern North Pacific Ocean. Gen. Comp. Endocrinol.
113830. doi:10.1016/j.ygcen.2021.113830

The goal of the present study was to complement existing data of
testosterone and progesterone in blue whale *(Balaenoptera musculus) *blubber
from the eastern North Pacific Ocean to evaluate effects of seasonality and
location on these hormones and to better assess reproductive status of
individuals. Physiological parameters regarding reproduction are
fundamental for describing population dynamics, and hormones can be a valid
tool to estimate those for wildlife populations. In this study, blubber
tissue was validated for testosterone and proges- terone assays. Hormone
concentrations were measured in 69 (35 males and 34 females) blubber
samples from live (n = 66) and stranded (n = 3) animals collected between
2002 and 2016 from a known winter reproductive ground in the Gulf of
California (GoC) and summer feeding areas along the United States West
Coast (USWC), specifically off the states of California and Oregon. Results
were combined with sighting histories as a tool to determine reproductive
status of individual whales. Testosterone concentrations in adult male blue
whales were significantly higher (p < 0.05) in blubber biopsies sampled off
the USWC between the months of June and November compared to those sampled
in the GoC between February and April. Elevated testosterone concentrations
likely indicate physiological preparation for reproductive activity while
the animals were present off the USWC. Progesterone concentrations were
significantly elevated in pregnant females, confirming progesterone as an
indicator of pregnancy in blue whales. Probabilities of being pregnant were
estimated for adult females with unknown sighting histories based on
progesterone concentrations. Testosterone in females was detected and
measured only in pregnant whales suggesting its biosynthesis or metabolism
is altered during gestation. These results provide updated and new
information on the reproductive cycle of blue whales in the eastern North
Pacific, posing new milestones to better estimate the timing of the mating
season for this endangered population.

The URL can be found here
or please contact valentinamelica88 at gmail.com to request a copy of the

Valentina Melica, PhD
Italy-US Fulbright Alumna

*Caminante, son tus huellas*
*el camino, y nada más;*
*caminante, no hay camino:*
*se hace camino al andar.*

Antonio Machado
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