Reactions of harbor porpoises Phocoena phocoena and herring Clupea harengus to acoustic alarms

Published source details Culik B.M., Koschinski S., Tregenza N. & Ellis G.M. (2001) Reactions of harbor porpoises Phocoena phocoena and herring Clupea harengus to acoustic alarms. Marine Ecology Progress Series, 211, 255-260.
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This study is summarised as evidence for the following.

	Action	Category
	Use acoustic devices on fishing gear Action Link

Use acoustic devices on fishing gear

A controlled study in 1999 in a fjord in the Fortune Channel, Vancouver Island, Canada (Culik et al. 2001) found that using an acoustic device on a float line resulted in harbour porpoise Phocoena phocoena groups approaching less closely. The average distance of porpoise groups from the centre of the float line was greater during trials with an active acoustic device attached (530 m) compared to trials before (150 m) or after (152 m). In June–July 1999, a float line was deployed during six days before an acoustic device was attached (total 26.5 h), five days with an acoustic device attached (emitting 300 ms pulses every 5–30 seconds at frequencies of 20–160 kHz; total 21 h), and two days after the device was removed (total 7 h). The float line (65 m long) had 10-m long weighted lines attached every 0.5 m. The acoustic device was attached to the centre of the float line, 30 cm below the water surface. Porpoises were tracked from the shore using a theodolite before (172 groups), during (44 groups) and after (22 groups) the acoustic device was attached. An acoustic detector deployed 1 m below the centre of the float line recorded porpoise echolocation clicks.

(Summarised by: Anna Berthinussen)