PAL Wideband Acoustic Device Reduces Endangered Black Sea Harbour Porpoise Bycatch by 74 Percent

Bulgarian researchers discover that PAL Wideband acoustic devices can save endangered harbour porpoises from commercial fishing nets in the Black Sea.

By: AXL Media

Published: Apr 28, 2026, 4:33 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Crisis of Europe’s Smallest Marine Mammal

The Black Sea harbour porpoise is currently navigating a perilous path toward extinction, largely driven by the high rates of bycatch in regional commercial fisheries. As an isolated population and the smallest marine mammal in Europe, the species is particularly vulnerable to bottom-set gillnets used in the turbot industry. Recent estimates suggest that more than 10,000 porpoises perish annually due to unintentional entanglement. In response, a team of Bulgarian researchers conducted a comprehensive four-year trial involving 57 hauls to determine if acoustic technology could provide a viable solution to this ecological emergency.

Trial Failures and the Search for Effective Deterrents

The research project, which documented cetacean bycatch in 61% of all monitored hauls, initially faced significant setbacks. The team tested two different models of acoustic deterrent devices, commonly referred to as pingers, but found them to be entirely ineffective at reducing mortality rates. During these early stages, the researchers recorded the deaths of 189 cetaceans, the vast majority of which were harbour porpoises, alongside a small number of bottlenose and common dolphins. These failures highlighted a critical technical gap in maritime conservation: not all acoustic signals are perceived by porpoises as a warning to avoid fishing gear.

Breakthrough Performance of Wideband Technology

A turning point in the study occurred with the introduction of the PAL Wideband pinger, a device developed in Germany. Unlike previous models, field trials demonstrated that this specific wideband device could reduce harbour porpoise bycatch in the Black Sea by approximately 74%. Experts attribute this success to the device's wide frequency band, which ranges between 10 and 150 kHz. This specific acoustic signature was the only one capable of consistently deterring porpoises from approaching the nets, suggesting that the complexity of the signal is more important than mere volume or repetitive tones.