‘About 3-4 weeks ago they dropped extra ones and have up to seven off each beach, when at the beginning of February, when the cull started, there were 1-3 hooks at each spot,’ filmmaker and former Department of Fisheries officer Shayne Thomson said.
Mr Thomson, cull observers and Cottesloe lifesavers saw hooks above markers, comprising one red buoy near a pair, increase from three to seven 1km off Cottesloe, City and Leighton-Port beaches after the Rottnest Channel Swim.
There were three hooks at Mullaloo and Trigg beaches in the protected Marmion Marine Park, three at Scarborough Beach and one at Swanbourne last week.
Mr Thomson said cull operators were attempting to be as humane as possible but shark revival techniques needed improvement, including not having sharks’ heads at the bottom of Fisheries vessels’ slipways where gravity worked against a hose pumping water into the animals’ gills.
He feared the mature 3m-4m female tiger shark could have been pregnant when she was shot at Port Beach about 7am on March 30, before being dumped near Rottnest Island.
‘If Perth is a tiger shark nursery then we are wasting a breeding stock of this relatively harmless species,’ he said.
However, James Cook University tiger shark specialist Professor Colin Simpfendorfer, who has researched the species in WA, said it was ‘impossible to tell with any certainty’ if the female was pregnant because she did not appear large for her size and it was unusual to catch pregnant females, which averaged about 40 pups at each birth.
A Department of Premier and Cabinet spokesman said it was always intended to increase the number of hooks.
‘No change, no reason, it was always the plan – five metro beaches, 36 drum lines,’ he said.
Asked why the large female was taken far offshore, he said crews worked to release sharks under 3m as ‘soon as possible’ to get the best survival rates.
‘This includes rapid handling, measurement and running water though the shark’s gills, as well as releasing the shark further out from the drum lines,’ the spokesman said.