Study

Effects of pingers on the behaviour of bottlenose dolphins

  • Published source details Leeney R.H., Berrow S., McGrath D., O'Brien J., Cosgrove R. & Godley B.J. (2007) Effects of pingers on the behaviour of bottlenose dolphins. Journal of the Marine Biological Association of the United Kingdom, 87, 129-133

Actions

This study is summarised as evidence for the following.

Action Category

Use acoustic devices on fishing vessels

Action Link
Marine and Freshwater Mammal Conservation

Use acoustic devices on moorings

Action Link
Marine and Freshwater Mammal Conservation
  1. Use acoustic devices on fishing vessels

    A controlled study in 2005 of a pelagic area in the Shannon Estuary, western Ireland (Leeney et al. 2007) reported that deploying active ‘continuous’ or ‘responsive’ acoustic devices alongside a boat resulted in common bottlenose dolphins Tursiops truncatus avoiding the boat more frequently than when inactive acoustic devices were deployed. Results are not based on assessments of statistical significance. Dolphins avoided a boat during more trials with active ‘continuous’ devices (3 of 4 trials) and active ‘responsive’ devices (3 of 4 trials) than with inactive ‘continuous’ devices (1 of 4 trials) or inactive ‘responsive’ devices (0 of 1 trial). Active ‘continuous’ or ‘responsive’ acoustic devices were deployed from the back of a 5.4-m rigid inflatable boat for four trials each. Inactive (silent) ‘continuous’ and ‘responsive’ acoustic devices were deployed for four trials and one trial respectively. Dolphin groups were approached to 50 m prior to the deployment of each device. ‘Continuous’ devices (Loughborough University/Aquatech prototype) continuously emitted sounds (<1 second sounds every 5–20 seconds at 5–20 kHz). ‘Responsive’ devices (Aquatec AquaMark) emitted sounds (300 ms sounds at 35–160 kHz) when dolphin clicks were detected by an internal microphone. Dolphin behaviour was observed for four minutes during each of the 13 trials in July 2005.

    (Summarised by: Anna Berthinussen)

  2. Use acoustic devices on moorings

    A controlled study in 2005 at six pelagic sites in the Shannon Estuary, western Ireland (Leeney et al. 2007) found that using ‘continuous’ acoustic devices on a mooring resulted in lower common bottlenose dolphin Tursiops truncatus echolocation activity compared to when inactive acoustic devices were used, but the difference was not significant for active and inactive ‘responsive’ acoustic devices. The average number of minutes in which dolphin echolocation clicks were detected was lower when ‘continuous’ acoustic devices were active (0 minutes/h; range: 0–0.05 minutes/h) than inactive (0.4 minutes/h; range: 0.2–1.1 minutes/h). The difference was not significant for ‘responsive’ acoustic devices that were active (0 minutes/h; range: 0–0.8 minutes/h) or inactive (0.6 minutes/h; range: 0.3–1.5 minutes/h). An active or inactive (silent) ‘continuous’ or ‘responsive’ acoustic device was randomly deployed at each of six sites for 3–5 x 24 h trials/treatment. ‘Continuous’ devices (Loughborough University/Aquatech prototype) continuously emitted sounds (<1 second sounds every 5–20 seconds at 5–20 kHz). ‘Responsive’ devices (Aquatec AQUAmark) emitted sounds (300 ms sounds at 35–160 kHz) when dolphin clicks were detected by an internal microphone. Devices were attached to a static mooring (line between an anchor and buoy), 5–12 m below the water surface. An acoustic logger recorded dolphin activity alongside the acoustic devices during each of 18 trials in July 2005.

    (Summarised by: Anna Berthinussen)

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 18

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust