Deterring harbour porpoise from gillnets: observed reactions to passive reflectors and pingers

Authors: 

Koschinski, S. & Culik, B.

Year: 

1997

Journal/Publisher Name: 

SC/48/SM14. Report of the International Whaling Commission 47

Page #s: 

659-668
Summary: 

Three different device types were mounted on floatline to test their potential for reducing harbor porpoise bycatch. The devices were two passive reflectors (target strength ranging from -38 dB to -24 dB) and a 2.9 kHz pinger. Behavioral responses of 355 harbor porpoise groups were monitored. 92.4% of the groups avoided the pinger equipped floatline, while only half the groups avoided the reflectors and control, empty, floatline.