"Our estimates
of resting metabolic rates and relative changes in total energy intake can be
used to parameterize bioenergetic models needed to estimate the ecological
impacts and energetic requirements of Pacific white-sided dolphins in the wild,
which will have conservation implications."
The partner paper
in a different journal (Rechsteiner, E. et al. 2013. Energy requirements of
Pacific white-sided dolphins (Lagenorhynchus
obliquidens) as predicted by a bioenergetic model. Journal of Mammalogy. 94(4) 820-832) also says that the study has
useful data for conservation.
But if you look in
the MS thesis from which this paper is derived you find:
“The
extent to which my results are representative of dolphins in the wild is
uncertain given that the behaviours and activities of dolphins in aquaria do
not necessarily mimic those of wild dolphins. I am also uncertain whether the
occasional heating of the water
in the dolphin habitat at the Vancouver Aquarium influenced my results, and I recognize
that my conclusions are limited by the small number of animals studied.
Despite
such shortcomings, the data collected from the three individuals represent the
most comprehensive energetics study conducted to date with Pacific white-sided
dolphins, and the only cetacean energetics study that has spanned multiple
seasons and examined both resting metabolic rates and total calories ingested”
(p.
49 in Rechsteiner, E. 2013. Testing metabolism,
energetics, and seasonal distribution of Pacific white-sided dolphins. MS thesis. University of British Columbia).
Throughout
the papers and thesis are statements about how these data can be used to inform
management, in particular issues relating to how many fish dolphins consume and
therefore potential conflicts with fisheries.
My
first thoughts when I read this were this could immediately be used by certain
bodies to try to justify culls of dolphins. Japan already has a large take of
Pacific white-sided dolphins (86 dolphins were
hunted in the 2010-2011 season; http://en.elsaenc.net/report/publiccomment/) and could use this study to
justify that by taking more dolphins they are protecting fisheries.
But really how representative of the thermoregulation and
energy use of wild populations are data from 3 individuals that live in a
heated pool (in contrast sea surface temperatures in the winter off of British Columbia
drop to 3oC), who move limited distances. Pacific-white sided dolphins
can move 10s of kilometers in a day, and importantly, are known to migrate,
including southwards to warmer waters of Southern California during the winter (e.g.
Leatherwood et al. 1988. Whales, Dolphins, and Porpoises of the Eastern North Pacific and
Adjacent Artic Waters. New York: Dover Publication). So how
representative of wild populations really is this study? Probably not very, yet
conservation decisions could be made on this study, which the authors appear to
be encouraging, but how many managers will read the caveats?
One of the problems with captive cetacean
facilities is that they are so desperate to suggest that they have value in the
modern world, especially to conservation, that they fiercely push and publicize
the few studies that they produce. However, if managers do use these studies
they are likely making the wrong decisions as the behavior and ecology of
captive animals is vastly different to wild animals. For example, using studies
on the sound sensitivity of captive cetaceans (which may suffer hearing loss
due to high noise exposure and medical treatments) to predict the impacts on
wild populations have wildly underestimates the sensitivity, and therefore underestimate
man-made noise impacts on, wild cetaceans (Wright, A.J. et al. 2009. Urging cautious policy applications of captive research data is not the
same as rejecting those data. Marine Pollution Bulletin 58: 314-316; Parsons,
E.C.M. et al. 2008. Navy sonar and cetaceans: just how much does the gun need to smoke before we act? Marine Pollution Bulletin 56: 1248-1257).
So, my take home
message is, studies on captive whales and dolphins have limited applicability to
the actual ecology and behavior of wild cetaceans, and as a such using these
studies to make conservation, management and policy decisions is inappropriate
and possibly even detrimental.