[MARMAM] New publication : Behavioural impact assessment of unmanned aerial vehicles on Weddell seals (Leptonychotes weddellii)

Laborie Joris joris.laborie at gmail.com
Sun Jan 17 12:52:12 PST 2021

 Dear MARMAM community,

My collaborators, Karine Heerah and I are pleased to share our new
publication, "Behavioural impact assessment of unmanned aerial vehicles on
seals (Leptonychotes weddellii)"

*Summary *: The rapid increase in the use of unmanned aerial vehicles
(UAVs) in wildlife research has raised concerns about its potential
negative impact on animals. The paucity of studies and the variability of
responses of pinnipeds to UAVs prompts the need for species-specific impact
assessments. Here we assessed the potential behavioural impact of low
altitude UAVs on Weddell seals (Leptonychotes weddellii). This is a
preliminary step to envisage the feasibility of replacing and/or
complementing traditional ground-based behavioural and morphometric
measurements by potentially less invasive UAV aerial images. We flew a
small UAV (DJI Mavic 2 zoom fitted with a phocid seal audiogram weighted
source level of 84 dB re 20 μ Pa (rms)) over 37 Weddell seals (3 adult
males, 12 adult females and 22 mother-pup pairs) during the breeding season
at Dumont D’Urville, East Antarctica. For each individual, we assessed the
level of reaction during UAV overflights at three altitudes (25, 20 and 15
m) while factoring in pup presence and wind speed. For all altitudes and
observations pooled together, Weddell seals predominantly (88%) showed
little (vigilant) or no (resting) reactions towards the UAV. Moreover, only
27% of all individuals changed their initial activity during the sampling
periods, and mothers rarely ended their nursing bouts (3%). While reactions
were low overall, the probability of a stronger reaction occurring
increased at lower altitudes, and varied among individuals. Neither the
presence of pups nor a change in wind speed appear to influence
individuals’ response to the UAV significantly. However, on simpler
histogram representations of the dataset, we observed the strongest
reactions for females (n = 5) with a pup at wind speeds below 5 m.s −1 when
ambient noise levels were lowest. While Weddell seals are likely to hear
the UAV at 25 to 15 m altitude in low wind speeds, the low-level responses
we observed are unlikely to negatively impact their energetic budget and/or
reproductive success. Our results suggest a low impact of small UAV
overflights of Weddell seals during the breeding season when flying ≥25 m.
This allows for collection of high resolution images for behavioural and
morphometric studies that can potentially replace more invasive data
collection when capturing and handling the animals.



Please do not hesitate to contact us with any questions !

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