Scientists in Tasmania will remove up to half of the island’s “emblematic” red handfish from the wild ahead of expected marine heatwaves deemed an existential threat to their survival.

The critically endangered Tasmanian red handfish population has fallen to between 50 and 100 in the wild, due to the degradation of the seaweed habitat it needs to breed.

The fish, which uses its over-sized fins for hands to walk across the sea floor, rather than swim, will now be housed at breeding facilities in Tasmania to protect them from the summer’s expected marine heatwaves.

Environment minister Tanya Plibersek said she had provided an exemption under federal environment law for scientists to collect up to 25 red handfish.

They will be housed at the Institute for Marine and Antarctic Studies (IMAS), which will be monitoring the remaining wild red handfish population for signs of stress, and if necessary, will collect the remaining fish and relocate them to the Institute’s facilities.

Plibersek said the government had also invested $240,000 to improve the condition of the species’ wild habitat and recover the health of captive animals.

“The Albanese Government has set a goal of no new extinctions, and this intervention is critical to save Tasmania’s red handfish,” Plibersek said in a statement.

Adrian Meder, the sustainable seafood program manager at the Australian Marine Conservation Society, said the fish was possibly the most endangered fin fish species in the world, with waters off south-eastern Australia warming at almost four times the global average.

“I would say a single adverse event could be the end of the species,” he said. “So this government intervention is very welcome.”

Meder said it was actually sea urchins, taking advantage of the warmer sea temperatures, that were causing the most damage.

“They are riding down on this tail of warm water, they’re growing faster, and they’re voraciously tearing up the red handfish habitat.”

There are 14 species of handfish off southern Australia, according to the Handfish Conservation Project.

The red handfish, which is known for its bright colours and stark face, is a “treasure”, Meder said.

“It literally looks like a Christmas decoration. They are beautiful and unusual creatures that are found nowhere else.

“They’re truly emblematic of Tasmania; they are weird, they are beautiful and they are ugly. And they’re an absolute treasure.”

Tasmania’s acting environment minister, Nic Street, said the remaining handfish population faced devastation unless action was taken.

“Extreme warming is predicted in the localised area the red handfish inhabits, with experts predicting population decline as high as 75-99% during the forecast conditions,” Street said.

Once the threat of marine heatwaves has passed, the fish are expected to be returned to the wild.