Long term effectiveness of an acoustic deterrent for seals in the Kyle of Sutherland
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Published source details
Harris R.N. (2011) Long term effectiveness of an acoustic deterrent for seals in the Kyle of Sutherland. Sea Mammal Research Unit (SMRU) report, SMRU, UK, Report to Scottish Government.
Published source details Harris R.N. (2011) Long term effectiveness of an acoustic deterrent for seals in the Kyle of Sutherland. Sea Mammal Research Unit (SMRU) report, SMRU, UK, Report to Scottish Government.
Actions
This study is summarised as evidence for the following.
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Use acoustic devices on moorings Action Link |
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Use acoustic devices on moorings
A controlled study in 2008–2011 at a river site in the Kyle of Sutherland estuary, Scotland, UK (Harris 2011) found that using acoustic devices reduced the overall number of grey seal Halichoerus grypus and harbour seal Phoca vitulina sightings, and fewer seals were sighted upstream than downstream of the devices. Overall, fewer seals were sighted/hour with the acoustic devices turned on than off (data reported as statistical model results). Fewer seals were sighted upstream of the devices than downstream when they were turned on, whereas numbers were similar with the devices turned off. Two acoustic devices (Lofitech Seal Scarers) were attached to piping on the opposite sides of an estuary (100 m wide, 2 m deep), 1–10 m from the bank, 0.3–1 m above the river bed. Rivers upstream of the estuary supported Atlantic salmon Salmo salar fisheries. During each of three winters (October–January) in 2008–2011, the devices were turned on (emitting 500 ms tones at 15 kHz) and off (silent) for alternating periods of 3–13 days. Seals were guided downstream by a boat with an acoustic device prior to each ‘on’ treatment. Seals were observed from the riverbank during surveys (each lasting 2–3 h) with the devices turned on (72 surveys) and off (80 surveys).
(Summarised by: Anna Berthinussen)
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