May 13 (UPI) -- Accidental catches of porpoises in fishing nets can be significantly reduced -- with no adverse behavioral consequences -- by the use of noise-emitting "pingers" off coastal areas, a British study has found.
With tens of thousands of small cetaceans such as dolphins being caught up in commercial fishing nets worldwide each year, scientists are sounding the alarm over their declining numbers.
But a study published Wednesday by the University of Exeter and Cornwall Wildlife Trust suggests technology could help alleviate the problem.
Researches found the use of pingers embedded in fishing nets resulted in a 37 percent reduction of harbor porpoise "bycatch" in an eight-month trial off Britain's Cornish coast.
It also demonstrated the acoustic alarms didn't permanently change their behavior. The animals immediately returned to their feeding grounds once the devices were turned off, the study's authors said.
"Thus, if pingers were to be deployed with static fishing nets, we would expect reduced net-porpoise interactions, thereby mitigating bycatch of harbor porpoises and, possibly, other cetacean species in the region," the study concluded.
The European Union mandates pingers for large fishing vessels of more than 12 meters, but those vessels represent only 2 percent of British fishers deploying static nets in 2017.
As many as 100,000 cetaceans, mostly dolphins, were accidentally accidentally caught in commercial nets in 2006, with current annual numbers thought to be around 80,000.