Spatial and temporal impact of pingers on porpoises

Authors: 
Carlstrom J., Berggren P., Tregenza N.J.C
Year: 
2009
Journal/Publisher Name: 
Can. J. Fish. Aquat. Sci
Volume/Issue #: 
66
Page #s: 
72-82
Publisher Address: 
NRC Research Press
Contact information: 
julia.carlstrom@aquabiota.se AquaBiota Water Research AB, Svante Arrhenius vag 21A, SE-104 05 Stockholm, Sweden
Authors investigated the spatial and temporal responses of porpoises to simulated bottom-set nets equipped with periodically operating Dukane NetMark 1000 pingers.
Field Studies:
Location Fishing gear Reduction technique Bycatch species Effect on bycatch species Catch Effect on target catch Type
Baltic Gillnets Acoustic pingers Small Cetaceans (maximum length < 7.5 meters) Pinger sound signficiantly reduced median echolocation encounter rate by 50% to 100% at porpoise click train detectors placed 500 m away. Reduced sighting rate up to 375 m from simulated net. The average distance of approach increased by 300 m. The return time was 6 hrs. when pingers were silent after being active for 24 hrs. and 50 min., compared to 2.5 hrs after pingers had been silent. None reported None reported In the wild