Effects of adding sounds to cod traps on the probability of collisions by humpback whales

Published source details Lien J., Barney W., Todd S., Seton R. & Guzzwell J. (1992) Effects of adding sounds to cod traps on the probability of collisions by humpback whales. Pages 701-708 in: A.J. Thomas, R.A. Kastelein & A.Y. Supin (eds.) Marine Mammal Sensory Systems. Plenum Press, New York.
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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, before-and-after study (year not stated) in eight pelagic areas in the North Atlantic Ocean, off the coast of Canada (Lien et al. 1992) found that cod Gadus morhua traps with acoustic devices attached had fewer humpback whale Megaptera novaeangliae collisions than traps without acoustic devices. The average number of humpback whale collisions was lower at traps after acoustic devices were installed (0.02 collisions/day) compared to before (0.4 collisions/day) or at control traps without acoustic devices (0.04 collisions/day). Average fish catches (including target species) were greater in traps with acoustic devices (686 kg/day) than those without (30–235 kg/day). In spring and summer, fishers deployed cod traps for 169 days before and 1,762 days after acoustic devices were installed. Control traps without acoustic devices were deployed for 2,223 days. Six or seven acoustic devices were attached to each trap (one at each corner, 2–3 on the leader section), 2 m below the water surface. Devices emitted sound pulses centred at 4 kHz every 3–6 seconds. Fishers recorded whale collisions and fish catches for each trap deployment.

(Summarised by: Anna Berthinussen)