Dear All
We are pleased to share our new publication “Estimating energetics in cetaceans
from respiratory frequency: why we need to understand physiology” that was
recently published in Biology Open. The study takes a closer look at the
possibility of obtaining reasonable estimates of metabolic rates from breathing
frequency in bottlenose dolphins.
A copy of the paper can be found at:
http://bio.biologists.org/content/biolopen/early/2016/03/16/bio.017251.full.pdf
<http://bio.biologists.org/content/biolopen/early/2016/03/16/bio.017251.full.pdf>
or by sending a request to afahl...@whoi.edu <mailto:afahl...@whoi.edu>
Title:Estimating energetics in cetaceans from respiratory frequency: why we
need to understand physiology
Authors: Fahlman, A., van der Hoop, J., Moore, M.J., Levine, G., Rocho-Levine,
J., Brodsky, M.
Journal: Biology Open
Year: 2016
Abstract: The accurate estimation of field metabolic rates (FMR) in wild
animals is a key component of bioenergetic models, and is important for
understanding the routine limitations for survival as well as individual
responses to disturbances or environmental changes. Several methods have been
used to estimate FMR, including accelerometer-derived activity budgets, isotope
dilution techniques, and proxies from heart rate. Counting the number of
breaths is another method used to assess FMR in cetaceans, which is attractive
in its simplicity and the ability to measure respiration frequency from visual
cues or data loggers. This method hinges on the assumption that over time a
constant tidal volume (VT) and O2 exchange fraction (ΔO2) can be used to
predict FMR. To test whether this method of estimating FMR is valid, we
measured breath-by-breath tidal volumes and expired O2 levels of bottlenose
dolphins, and computed the O2 consumption rate (V̇ O2) before and after a
pre-determined duration of exercise. The measured V̇ O2 was compared with three
methods to estimate FMR. Each method to estimate V̇ O2 included variable VT
and/or ΔO2. Two assumption-based methods overestimated V̇ O2 by 216-501%. Once
the temporal changes in cardio-respiratory physiology, such as variation in VT
and ΔO2, were taken into account, pre-exercise resting V̇ O2 was predicted to
within 2%, and post-exercise V̇ O2 was overestimated by 12%. Our data show that
a better understanding of cardiorespiratory physiology significantly improves
the ability to estimate metabolic rate from respiratory frequency, and further
emphasizes the importance of eco-physiology for conservation management efforts.
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