Risk versus reward: Interactions, depredation rates, and bycatch mitigation of dolphins in demersal fish trawls

  • Published source details Santana-Garcon J., Wakefield C.B., Dorman S.B., Denham A., Blight S., Molony B.W. & Newman S.J. (2018) Risk versus reward: Interactions, depredation rates, and bycatch mitigation of dolphins in demersal fish trawls. Canadian Journal of Fisheries and Aquatic Sciences, 75, 2233-2240.


This study is summarised as evidence for the following.

Action Category

Use acoustic devices on fishing gear

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

    A controlled study in 2013 of a pelagic area in the Indian Ocean, northwest Australia (Santana-Garcon et al. 2018) found that trawl nets with acoustic devices attached had a similar number and duration of common bottlenose dolphin Tursiops truncatus interactions compared to trawl nets without acoustic devices. Average daily interaction rates of dolphins with trawl nets did not differ significantly between nets with acoustic devices (0.7 interactions/minute) and without (0.4 interactions/minute). The average duration of interactions also did not differ significantly with acoustic devices (1.7 minutes) or without (1.3 minutes). Three commercial vessels carried out 14 trawls with acoustic devices attached to trawl nets and 17 trawls without acoustic devices. Dolphin Dissuasive Devices (emitting random frequencies between 2 and 500 kHz) were attached on either side of an underwater video camera installed within each trawl net. All trawls were carried out during the day with a single stern trawl net towed close to the seabed in water 50–100 m deep. Video cameras recorded dolphin interactions with the nets during each of the 31 trawls in January–February 2013.

    (Summarised by: Anna Berthinussen)

Output references
What Works 2021 cover

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, 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 21

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 ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust