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Post-disturbance haulout behaviour of harbour seals

Paterson, William D.; Russell, Debbie J.F.; Wu, Gi-Mick; McConnell, Bernie; Currie, John I.; McCafferty, Dominick J.; Thompson, Dave


William D. Paterson

Debbie J.F. Russell

Gi-Mick Wu

Bernie McConnell

Dominick J. McCafferty

Dave Thompson


1. The impact of anthropogenic activity associated with the construction of a proposed tidal turbine on harbour seals (Phoca vitulina) was investigated using controlled disturbance trials.
2. Trials were conducted by approaching hauled out seals by boat at a speed of five knots until all seals had entered the water. Trials were carried out at a frequency of once every three days when weather permitted and the post disturbance haulout behaviours of the seals were documented. The time taken for numbers to recover to pre-disturbance levels was determined by monitoring haulout sites using time-lapse photography. In addition, seals were tagged with GPS phone tags providing haulout location and at-sea movement data allowing investigation of how disturbance may influence haulout site choice and seal distribution.
3. Mean post-disturbance recovery of seals was 52% (95%CI 35-69%) within 30 minutes. However, mean recovery only returned to 94% (95%CI 55-132%) of pre-disturbance levels after four hours.
4. Telemetry tagged seals displayed a high degree of haulout site fidelity. Disturbance trials did not have a significant effect on the probability of seals moving to a different haulout site.
5. The results of this study suggest that increased boat activity that causes seals to enter the water at a higher than normal frequency will not cause individuals to relocate to another haulout site. Seals continued to return to the original site despite repeated disturbance trials suggesting that increased boat activity is likely to repeatedly impact on the same seals with the largest effect being to reduce the amount of time available to seals to haul out.
6. This study recommends that monitoring effort to mitigate against increased levels of disturbance caused by boat activity need only be on a local scale relative to any proposed development.

Journal Article Type Article
Acceptance Date Feb 19, 2019
Online Publication Date Sep 6, 2019
Publication Date Sep 6, 2019
Deposit Date Jul 17, 2017
Publicly Available Date Jul 18, 2017
Journal Aquatic Conservation: Marine and Freshwater Ecosystems
Print ISSN 1052-7613
Electronic ISSN 1099-0755
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 29
Issue S1
Pages 144-156
Keywords Harbour seals, behaviour, coastal, disturbance, hydropower, intertidal, mammals, renewable energy
Public URL
Contract Date Jul 17, 2017


Post-disturbance Haulout Behaviour Of Harbour Seals (937 Kb)

Copyright Statement
This is the peer reviewed version of the following article: Paterson WD, Russell DJF, Wu G‐M,et al. Post‐disturbance haulout behaviour of harbour seals.Aquatic Conserv: Mar Freshw Ecosyst. 2019;29(S1):144–156, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

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