Shock tactics deter sharks from death

Scientists think they may have a way to shock sharks into avoiding fishing nets – something which kills up to 13 million of the fish a year.

Electric fields generated by electropositive alloys appeared to deter sharks by overloading their sensory system

Recent research from the US National Oceanic and Atmospheric Administration has shown that the sensitive electroreceptive system of sharks, which detects weak electric fields including those generated by their prey, could be exploited to repel sharks from fishing nets.

Diminishing populations of sharks are threatening the marine ecosystem and this is partly due to shark bycatch in fishing; an estimated 11 to 13 million sharks die worldwide by accidently being caught in fishing nets. Not only does this affect sea life, it also reduces fishing efficiency and increases operating costs.

Electric fields generated by electropositive alloys appeared to deter sharks by overloading their sensory system. “Individual sandbar sharks would generally not approach the metal ingots closer than about 24 inches, nor attack pieces of cut bait suspended within approximately 12 inches,” said Richard Brill, a research scientists at NOAA’s Northeast Fisheries Science Centre. “This study clearly shows the alloy has the potential to repel sharks, but the optimal size and shape of the alloy and other factors needs to be determined. This is a promising step.”

Although electronic devices capable of repelling sharks have been designed, they are large and impractical for large scale fishing. These new findings hope to provide a viable alternative to save shark populations. The alloy used was palladium neodymium and appeared to be a good alternative to more expensive metals and is machinable and reasonably resistant to seawater corrosion. The group look forward to conducting field trials in the near future.

By Leila Sattary