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Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals (Halichoerus grypus) at breeding colonies in Nova Scotia, Canada.

Publication ,  Journal Article
Arona, L; Dale, J; Heaslip, SG; Hammill, MO; Johnston, DW
Published in: PeerJ
January 2018

The use of small unoccupied aircraft systems (UAS) for ecological studies and wildlife population assessments is increasing. These methods can provide significant benefits in terms of costs and reductions in human risk, but little is known if UAS-based approaches cause disturbance of animals during operations. To address this knowledge gap, we conducted a series of UAS flights at gray seal breeding colonies on Hay and Saddle Islands in Nova Scotia, Canada. Using a small fixed-wing UAS, we assessed both immediate and short-term effects of surveys using sequential image analysis and between-flight seal counts in ten, 50 m2 random quadrats at each colony. Counts of adult gray seals and young-of-the-year animals between first and second flights revealed no changes in abundance in quadrats (matched pair t-test p > 0.69) and slopes approaching 1 for linear regression comparisons (r2 > 0.80). Sequential image analysis revealed no changes in orientation or posture of imaged animals. We also assessed the acoustic properties of the small UAS in relation to low ambient noise conditions using sound equivalent level (Leq) measurements with a calibrated U-MIK 1 and a 1/3 octave band soundscape approach. The results of Leq measurements indicate that small fixed-wing UAS are quiet, with most energy above 160 Hz, and that levels across 1/3 octave bands do not greatly exceed ambient acoustic measurements in a quiet field during operations at standard survey altitudes. As such, this platform is unlikely to acoustically disturb gray seals at breeding colonies during population surveys. The results of the present study indicate that the effects of small fixed-wing UAS on gray seals at breeding colonies are negligible, and that fixed-wing UAS-based approaches should be considered amongst best practices for assessing gray seal colonies.

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Published In

PeerJ

DOI

EISSN

2167-8359

ISSN

2167-8359

Publication Date

January 2018

Volume

6

Start / End Page

e4467

Related Subject Headings

  • 11 Medical and Health Sciences
  • 06 Biological Sciences
 

Citation

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ICMJE
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Arona, L., Dale, J., Heaslip, S. G., Hammill, M. O., & Johnston, D. W. (2018). Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals (Halichoerus grypus) at breeding colonies in Nova Scotia, Canada. PeerJ, 6, e4467. https://doi.org/10.7717/peerj.4467
Arona, Lauren, Julian Dale, Susan G. Heaslip, Michael O. Hammill, and David W. Johnston. “Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals (Halichoerus grypus) at breeding colonies in Nova Scotia, Canada.PeerJ 6 (January 2018): e4467. https://doi.org/10.7717/peerj.4467.

Published In

PeerJ

DOI

EISSN

2167-8359

ISSN

2167-8359

Publication Date

January 2018

Volume

6

Start / End Page

e4467

Related Subject Headings

  • 11 Medical and Health Sciences
  • 06 Biological Sciences