Acoustic alarms reduce porpoise mortality

@article{Kraus1997AcousticAR,
  title={Acoustic alarms reduce porpoise mortality},
  author={Scott D. Kraus and Andrew J. Read and Andrew R. Solow and Kenneth C. Baldwin and Trevor R. Spradlin and Eric Anderson and J. G. Williamson},
  journal={Nature},
  year={1997},
  volume={388},
  pages={525-525}
}
The most serious danger to dolphins and porpoises around the world is the threat from various forms of gill-net fishing. One potential way to reduce the number of deaths of marine mammals is the use of active acoustic alarms to warn animals about the presence of nets. Until now, acoustic alarms have not been tested in field experiments with sufficient statistical power. Here we describe a field experiment showing that acoustic alarms are effective at reducing the number of deaths of harbour… 
Observations of Harbor Porpoise in the Vicinity of Acoustic Alarms on a Set Gill Net
Large and small-scale fishery experiments have demonstrated that attaching acoustic devices (pingers) on gill nets reduces harbor porpoise (Phocoenaphocoena) entanglement and mortality. However, the
PORPOISE MONITORING IN PINGER-NET FISHERY
Harbour porpoises are part of the assignment of 16 Natura 2000 areas in Danish waters and Denmark are obliged to monitor and protect the species. The harbour porpoise faces the threat of entanglement
Acoustic alarms elicit only subtle responses in the behaviour of tropical coastal dolphins in Queensland, Australia
Incidental bycatch in gill nets is the most serious of the global threats to marine mammals. Consequently, many management agencies wish to implement practical and efficient bycatch mitigation
Reactions of harbor porpoises Phocoena phocoena and herring Clupea harengus to acoustic alarms
Small cetaceans are susceptible to incidental mortality in the various forms of gillnet fisheries throughout their range. Research conducted since 1994 has shown that acoustic alarms (pingers)
Effects of commercially-available acoustic alarms, designed to reduce small cetacean bycatch in gillnet fisheries, on the behaviour of North Sea fish species in a large tank
World-wide many cetaceans drown incidentally in fishing nets. To reduce the unwanted bycatch in gillnets, pingers (acoustic alarms) have been developed that are attached to the nets. In the European
Cetaceans and Humans: Influences of Noise
Whales, dolphins and porpoises face a multitude of problems at the hands of humans. These include incidental kills in fishing nets and lines, direct kills for food or bait, debilitation (and death)
An investigation of acoustic deterrent devices to reduce cetacean bycatch in an inshore set net fishery
In Europe, problems with the use of pingers on larger fishing vessels have raised the question as to whether pingers would be practical on smaller vessels, which are a large proportion of the
Responses of cetaceans to anthropogenic noise
1 Since the last thorough review of the effects of anthropogenic noise on cetaceans in 1995, a substantial number of research reports has been published and our ability to document response(s), or
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References

The herring ear has a unique receptor pattern
TLDR
Scanning electron microscopic (SEM) investigations of the otolith sensory epithelial surfaces have revealed several additional structural aspects of the herring utricle which may further support a hypothesis for an auditory role for this organ in clupeids.