Echolocation behavior of harbor porpoises Phocoena phocoena around chemically enhanced gill nets
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Published source details
Cox T.M. & Read A.J. (2004) Echolocation behavior of harbor porpoises Phocoena phocoena around chemically enhanced gill nets. Marine Ecology Progress Series, 279, 275-282.
Published source details Cox T.M. & Read A.J. (2004) Echolocation behavior of harbor porpoises Phocoena phocoena around chemically enhanced gill nets. Marine Ecology Progress Series, 279, 275-282.
Actions
This study is summarised as evidence for the following.
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Use acoustically reflective fishing gear materials Action Link |
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Use acoustically reflective fishing gear materials
A controlled study in 2000 of a pelagic area in the Bay of Fundy, Canada (Cox & Read 2004) found that fishing nets made from acoustically reflective materials (barium sulfate) had similar harbour porpoise Phocoena phocoena echolocation activity around them compared to conventional nets. The average occurrence and rate of porpoise echolocation clicks were similar at barium sulfate nets (18–54 intervals with clicks/h; 32–52 clicks/h) and conventional nets (17–57 intervals with clicks/h; 18–54 clicks/h). Average catches of target groundfish species did not differ significantly between barium sulfate nets (0.41 fish/h) and conventional nets (0.38 fish/h). In July–August 2000, nine barium sulfate and 14 conventional gill net strings were deployed across a fishing area (same study site and nets as Trippel et al. 2009). All strings (comprising 3 x 100 m nets, 15 cm stretched monofilament mesh) were deployed on the ocean bottom at depths of 100–130 m for 24–72 h. Four acoustic detectors attached to each of the 23 net strings continuously recorded porpoise echolocation activity at 10 second intervals for a total of 225 h on barium sulfate nets and 366 h on conventional nets.
(Summarised by: Anna Berthinussen)
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