A trial of acoustic harassment device efficacy on free-ranging bottlenose dolphins in Sardinia, Italy

Published source details López B.D. & Mariño F. (2011) A trial of acoustic harassment device efficacy on free-ranging bottlenose dolphins in Sardinia, Italy. Marine and Freshwater Behaviour and Physiology, 44, 197-208.
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This study is summarised as evidence for the following.

	Action	Category
	Use acoustic devices at aquaculture systems Action Link

Use acoustic devices at aquaculture systems

A before-and-after study in 2009 at a fin-fish farm in the Mediterranean Sea, off the coast of Sardinia, Italy (López & Mariño 2011) found that an active acoustic device did not reduce common bottlenose dolphin Tursiops truncatus presence, approach distances, group size or time spent in the area compared to before or after the device was active. Bottlenose dolphin presence and minimum approach distances did not differ significantly before, during or after the acoustic device was active (data not reported). The same was true for average dolphin group sizes (before: 2 dolphins; during: 5 dolphins; after: 3 dolphins) and the average time dolphins spent in the area (before: 15 minutes; during: 19 minutes; after: 23 minutes). In February–June 2009, an acoustic device attached to a fish cage was activated (emitting 1.2–1.8 second tones at 6.2–9.8 kHz) for 40 minutes during each of 144 trials. The fish farm (12,000 m²) consisted of 21 floating nylon mesh cages, 200 m from the shore. During each trial, dolphins were observed from a stationary boat during 40-minute periods before, during and after the device was active. Thirty periods for each of the three stages (before, during, after) were randomly selected for analysis.

(Summarised by: Anna Berthinussen)