There is a hidden desert along the east coast of Australia that has conservationists and the seafood industry concerned.

Key points: Sea urchin supplier says 'Centro' population is getting out of control

Sea urchin supplier says 'Centro' population is getting out of control Supplier says a profitable sea urchin industry could offer long term solution

Supplier says a profitable sea urchin industry could offer long term solution Diver says Victoria's abalone industry culling of urchins proven it can help

Sea urchins on the coastal floor are wiping out the seaweed habitat and leaving a barren white rock "moonscape" in their wake.

Rachel Theodore runs a small business on the far south coast of New South Wales in Tomakin, diving and processing sea urchins for the domestic market.

She said the sea urchin population was out of control and getting worse.

"There's only one urchin — the Centro urchin — that is a problem, it's the purpley black one that everyone sees when they go for a dive," she said.

Rachel Theodore runs a small business in Tomakin on the far south coast of NSW, diving and processing sea urchins for the domestic market. ( ABC News: Ruby Mitchell )

Ms Theodore said they had become a pest, with their numbers so high they were causing an imbalance in the biodiversity of the area.

"The Centro can eat just everything, they can move within about four metres every month — so it's quite fast for a little creature that looks like it can't move," she said.

"But it will just wipe out everything, it can even eat rock when it's got nothing else to eat, and it will survive there for 10 years or more just on nothing."

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'Culling sea urchins proven to help'

Ms Theodore believes a profitable sea urchin industry could offer a long-term solution.

She said the state's current regulations were protecting the creatures at the expense of the marine park.

"With the marine parks and the DPI sanctuary zones, the Centro has been allowed to flourish," she said.

"Our biggest struggle is we are on probably the best piece of coast there is — [but] right here at our boat ramp we can't dive.

"On rough weather days we have to ship [sea urchins] up from Victoria just so we can keep supply up.

"That all costs heaps of money, when we've got everything right here at our door step, but the marine park won't let us in."

John Smyth says the abalone industry in Victoria has proven that culling sea urchins can help. ( ABC News: Ruby Mitchell )

Abalone diver John Smyth has been filming his dives along the NSW coast, culling sea urchins and monitoring the recovery.

He said in Mallacoota, in eastern Victoria, the abalone industry had proven that culling sea urchins could help.

"It's a win win for the abalone fishery and the sea urchin fishery," he said.

"Because they're not taking all the urchins out, they're reducing the density, the amount of weed means there's more food for both abalone and sea urchins.

"So the urchin roe quality from Mallacoota is very high and marketable, so they've increased their fishing for urchins and also increased the areas where they can catch their abalone from."

'Population normally fluctuates throughout the year'

Ms Theodore says sea urchin numbers are causing an imbalance in the biodiversity of the area. ( Facebook: ABC South East NSW )

In response, the NSW Department of Primary Industries said the population of sea urchins fluctuated throughout the year.

And they said the presence of urchin barrens in NSW was due to a reduction in the abundance of key urchin predators.

"While sea urchins are not a significant risk to the marine estate, they are undertaking monitoring work inside and outside of marine park sanctuary zones to further assess impact," a spokesperson said in a statement.