Underwater sound-emitting devices (maximum level of intensity equivalent to approximately 175 dB re 1 µPa @ 1m) attached to fishing gear, principally gillnets. [Under NOAA’s Harbor Porpoise Take Reduction Plan for the Gulf of Maine, the sound output intensity for pingers is stipulated as 10 (±2) kHz at 132 (±4) dB re 1 µPa @ 1m (NMFS/NOAA, 1998)]. Pingers are now mandated for use in some fisheries in the U.S. Northwest Atlantic, California driftnet, and in Europe. The sound of these devices is believed to alert an animal to the presence of the net and thus decrease the probability of entanglement. Although some studies have shown that pingers can have the unintended consequence of attracting pinnipeds to fishing operations (Bordino et al., 2002), this may be controllable by raising the emitted frequency of the pingers above seal hearing (Kraus et al., 1997).
Submitted by morgaac on May 18, 2016 – 11:57
Humpback whales responded to ‘tones’ by moving offshore and surfacing more often, perhaps trying to avoid the stimuli. Responses to social sounds were more variable.
- Megaptera novaeangliae (Humpback whale)
Submitted by morgaac on May 13, 2016 – 09:46
Submitted by morgaac on May 13, 2016 – 09:16
The current net/pinger configuration is adequate for humpback whales, dugongs and dolphins swimming at normal travelling speeds. The current pinger spacing is insufficient for dolphins swimming straight at the net at high speeds. Acoustic investigation of bycatch mitigation pingers
Submitted by morgaac on March 31, 2016 – 13:22
Submitted by morgaac on March 30, 2016 – 17:30
Submitted by morgaac on March 28, 2016 – 18:53
Submitted by morgaac on August 19, 2015 – 16:53
Submitted by Kate McClellan on March 3, 2014 – 14:56
Submitted by Kate McClellan on January 6, 2014 – 16:34
Submitted by Kate McClellan on January 6, 2014 – 15:28