The Baird government's decision to drop its opposition to shark nets for the state's northern beaches ignored recommendations of one of its own departments and the scientific consensus, experts say.

The unintended impacts of shark mesh was on show on Saturday, with a juvenile humpback whale becoming entangled in a net near Coolangatta on the Gold Coast. The calf's mother helped keep the animal near the surface long enough for a patrol to arrive and cut the whale free.

Another shark bite last week – the sixth since the start of 2015 for the Ballina-Byron area alone – was the last straw for Premier Mike Baird. On Wednesday, he explained his backflip, saying it was time to "prioritise human life over everything".

Only one fatality has been recorded in the state's 51 netted beaches since their introduction in Sydney in 1937, back in 1951. There have, though, been 33 so-called unprovoked attacks some serious ones.