Dear Colleagues,
My co-authors and I are pleased to announce our most recent article, published
in Conservation Physiology:
Clark, C.T., A.H. Fleming, J. Calambokidis, N.M. Kellar, C.D. Allen, K.N.
Catelani, M. Robbins, N.E. Beaulieu, D. Steel, and J.T. Harvey. 2016. Heavy
with child? Pregnancy status and stable isotopes as determined from biopsies of
humpback whales. Conservation Physiology. DOI: 10.1093/conphys/cow050
Abstract:
Understanding reproductive rates of wild animal populations is
crucially important for management and conservation. Assessing pregnancy status
of free-ranging cetaceans has historically been difficult; however, recent
advances in analytical techniques have allowed the diagnosis of pregnancy from
small samples of blubber tissue. The primary objectives of this study were as
follows: (i) to test the efficacy of blubber progesterone assays as a tool for
diagnosing pregnancy in humpback whales (Megaptera novaeangliae); (ii) to
estimate the pregnancy rate of humpback whales in Monterey Bay, California; and
(iii) to investigate the relationship between stable isotopes and reproductive
status of these whales. Progesterone concentrations of female whales fell into
two distinct groups, allowing for diagnostic separation of pregnant and
non-pregnant individuals. Pregnancy rate varied between years of the study
(48.4%% in 2011 and 18.5% in 2012), but fell within the range of other
estimates of reproductive success for this population. Stable carbon and
nitrogen isotope ratios were examined to investigate the impacts of pregnancy
on these values. Neither δ15N nor δ13C varied in a consistent way among animals
of different sex or reproductive status. The relationship between δ15N and δ13C
was strongly positive for male and non-pregnant female humpbacks; however, no
relationship existed for pregnant whales. This difference may be indicative of
the effects of pregnancy on δ15N, resulting from tissue synthesis and reduced
excretion of nitrogenous waste, as well as on δ13C through increased
mobilization of lipid stores to meet the energetic demands of pregnancy.
Ultimately, our results support the use of blubber progesterone assays for
diagnosing pregnancy in humpback whales and indicate that, when paired with
other approaches (e.g. stable isotope analysis), pregnancy status can be an
informative tool for addressing questions about animal physiology, ecology and
population biology. This information will provide for more effective management
and conservation efforts in a rapidly changing world.
The full text can be downloaded here:
http://conphys.oxfordjournals.org/cgi/content/full/cow050?
<http://conphys.oxfordjournals.org/cgi/content/full/cow050?ijkey=UIIa5TFqN4qUGL5&keytype=ref>ijkey=UIIa5TFqN4qUGL5&keytype=ref
<http://conphys.oxfordjournals.org/cgi/content/full/cow050?ijkey=UIIa5TFqN4qUGL5&keytype=ref>
Best regards,
Casey Clark
PhD Candidate
CFOS/WERC
University of Alaska Fairbanks
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