Smultea Sciences and my co-author and I are pleased to announce and share an
Open Access PDF link to our recent publication entitled "Assessing 'observer
effects' from an aircraft on behavior of three Delphinidae species (Grampus
griseus, Delphinus delphis, and Orcinus orca)" in the journal Wildlife Biology
in Practice based on our observations, video and photos taken from a circling
research aircraft during 2009-2011.
Abstract
We systematically video-documented three species of Delphinidae: Risso's
dolphin (Grampus griseus), short-beaked common dolphin (Delphinus delphis), and
killer whale (Orcinus orca) in the Southern California Bight (2009-2011) to
assess whether the observation aircraft (fixed-wing Partenavia) affected
selected behavioral variables. Focal observations were conducted to examine
potential changes in group cohesion and heading reorientation rate, to the
plane circling at four altitudes: 213 m, 305 m, 457 m, and 610 m, while
maintaining a radial distance >500 m. Paired t-tests were used to test the null
hypothesis that mean maximum cohesion and mean reorientation of groups do not
vary significantly based on plane altitude. For cohesion, no significant
effects were found for the eight G. griseus focal sessions (p = 0.447), one D.
delphis (p = 0.602), and one O. orca (p = 0.197). For reorientation, no
significant effects were found for the eight G. griseus focal sessions (p =
0.591) and one O. orca (p = 0.936); the sample size was too small to calculate
reorientation for D. delphis. Our results suggest that our small plane circling
at radial distance >500 m and altitude 213 - 610 m did not cause measurable
changes in cohesion and reorientation or other observable changes for the three
species. We believe this is due to the aircraft remaining >500 m radial
distance from the animals and at altitudes well outside the theoretical
26-degree sound transmission cone ("Snell's Cone") below the aircraft for the
air-through-water interface.
This article can be found at:
http://socpvs.org/journals/index.php/wbp/article/view/10.2461-wbp.2016.12.8
Mari A. Smultea, MSc, PhD
Chief Scientist/CEO
Smultea Sciences (SES)
m...@smulteasciences.com<mailto:m...@smulteasciences.com>
www.smulteasciences.com<http://www.smulteasciences.com/>
(707) 362-5376
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