Why shark drumline data is wrong

 

A SCIENTIST who worked on Queensland's shark control program says data used to justify taking out drumlines is flawed because of a clever act by dolphins.

Cairns-based fisheries scientist Geoff McPherson worked for the Queensland Government's shark control program from 1991 to 2006, where he was responsible for identifying sharks captured along Queensland's east coast, and finding ways to deter them from local beaches.

Mr McPherson said bait used on drumlines for the program was frequently taken by dolphins, who had grown accustomed to avoiding being hooked.

He said as a result, the data from the control program had become flawed as it showed fewer sharks were being captured, with conservationists claiming sharks had therefore become less abundant within the Great Barrier Reef Marine Park.

"Dolphins have been stealing baits from the gear for so long, the (shark catch) data is so wrong, it's not funny," he said.

Retired fisheries officer Geoff McPherson believes dolphins have skewed data that was used to justify taking out drumlines. PICTURE: ANNA ROGERS
Retired fisheries officer Geoff McPherson believes dolphins have skewed data that was used to justify taking out drumlines. PICTURE: ANNA ROGERS

Dolphins have long been regarded to have been "accidental bycatch" of the shark control program, with data showing 76 dolphins died after being hooked on drumlines between 2009 and 2014.

The numbers of non-target species being caught as part of the catch-and-cull program, was used by conservationists in the landmark court case to have the program scrapped within the Great Barrier Reef marine park.

 

This tiger shark was said to have been filmed hooked to a drum line off the coast of Magnetic Island. Picture: Humane Society International.
This tiger shark was said to have been filmed hooked to a drum line off the coast of Magnetic Island. Picture: Humane Society International.

 

Mr McPherson did not know the solution to deterring dolphins from taking bait attached to drumlines.

But he backed calls for traditional drumlines to be redeployed at all of Cairns' beaches, suggesting a catch and release, SMART drumline program simply would not work.

"SMART drumlines are based on catching and towing away 500 body lengths," he said. "Catching a shark off Palm Cove Surf Life Saving Club, towing it to Sea Temple and expecting it to go away is ludicrous."