Authors investigated the spatial and temporal responses of harbor porpoises (Phocoena phocoena) to simulated bottom-set nets equipped with periodically operating Dukane NetMark 1000 pingers. Pinger sound significantly reduced the median echolocation encounter rate by 50-100% at detectors placed up to 500m and reduced the sighting rate up to 375m from the simulated net. The average distance of approach also increased. When pingers were silent after being active for about two days, the return time of porpoises increased by several hours in comparison to a control. After about 50 days, habituation to the pingers was detected at two of nine stations. Pingers may affect harbor porpoises at greater distances than previously observed, but alternative solutions should be applied in ecologically important habitats and migration routes.
Year
Journal/Publisher Name
Can. J. Fish. Aquat. Sci
Volume (Issue #)
66
Page #s
72-82
Contact information
J. Carlström:
julia.carlstrom@aquabiota.se
AquaBiota Water Research AB, Svante Arrhenius
vag 21A, SE-104 05 Stockholm, Sweden
julia.carlstrom@aquabiota.se
AquaBiota Water Research AB, Svante Arrhenius
vag 21A, SE-104 05 Stockholm, Sweden
Summary
Field Studies
Spatial and temporal impact of pingers on porpoises
Study Type
Field study in the wild
Location
Scotland
Target catch
N/A
Effect on bycatch species
Pingers significantly reduced echolocation encounter rates by 50-100% at 500m; sighting reduced up to 375m. Porpoise return time was 6 hrs when pingers were silent after being active for 24 hrs 50 min
Effect on target catch
N/A
Reduction technique
Fishing Gear