Study

Behavioral responses of bottlenose dolphins, Tursiops truncatus, to gillnets and acoustic alarms

  • Published source details Cox T.M., Read A.J., Swanner D., Urian K. & Waples D. (2003) Behavioral responses of bottlenose dolphins, Tursiops truncatus, to gillnets and acoustic alarms. Biological Conservation, 115, 203-212

Actions

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 randomized, controlled study in 2001 at a coastal site in the North Atlantic Ocean, off the coast of North Carolina, USA (Cox et al. 2003) found that fishing nets with active acoustic devices were approached within 100 m by fewer common bottlenose dolphin Tursiops truncatus groups than nets with inactive devices, although the number of dolphin groups observed within 300 m of the nets and average closest approach distances were similar. Fewer dolphin groups approached within 100 m of nets with active acoustic devices (2 of 25 groups, 8%) than inactive devices (7 of 15 groups, 47%). The average number of dolphin groups observed within 300 m of the nets and average closest approach distances did not differ significantly with active (0.4 groups/h; 47 m) or inactive (0.6 groups/h; 38 m) acoustic devices. A gill net was deployed on random days with three active acoustic devices attached (Dukane NetMark 1000, emitting regular interval pulses at 10 kHz; total 13 days) or three inactive (silent) acoustic devices (total nine days). The net (200 m long, stretched mesh size 76 mm) was deployed 300 m from a beach perpendicular to the shore in water 3–6 m deep. Two observers tracked 40 dolphin groups from the shore using a theodolite over 22 days in April–May 2001.

    (Summarised by: Anna Berthinussen)

Output references

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