The South Australian government will use explosives to scare fur seals away from fishing areas, after rejecting a call to start killing the animals.

The number of long-nosed, or New Zealand, fur seals around Coorong has soared in recent years to about 100,000. The seals, which are found along southern Australia and New Zealand, have irked fishing crews by eating their catches and ripping holes in their nets.

A South Australian Liberal MP has put forward a private member’s bill to enable the shooting of the seals to reduce their numbers, a move backed by some fishers.

But the state government has rejected this idea, instead investing $100,000 in “humane, non-lethal deterrents” such as underwater explosives called “seal scarers”.

Manufacturers of seal scarers say the devices are extremely unpleasant for seals but do not affect fish.

The explosives are placed near fishing crews and their nets and are aimed at frightening seals so they don’t plunder the fishers’ catch or damage their nets.

The money will also be used to research new fishing equipment and practices to alleviate the problem.

Fur seals were almost wiped out by hunters in the 18th and 19th centuries, but numbers have now rebounded to healthy levels. The seals can dive as far as 240m underwater to forage for food, for up to 10 minutes each time.

The seals, which can live as long as 17 years, feed on a wide range of marine life, including squid, eels, mackerel and barracuda.

“The best science is showing that culling is not the answer to managing interactions between fur seals and fishers,” said Ian Hunter, South Australia’s environment minister.

“Experience from overseas fisheries has shown selective culling is ineffective, as removing one seal means that another will simply move in to take advantage of the available food.”

Hunter said relocation was also problematic as seals often returned to their previous location within days. Explosives were now the best option, he said.

“There is no reason that we cannot have healthy fisheries while also protecting the native animals that are such a drawcard for tourists to South Australia,” he said.