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Published: 8 Nov 2021

Is this the pest you need in your garden? Scientists researching the benefits of sea urchin fertiliser seems to think so.

Marine scientist John Keane is among a team of researchers testing the fertiliser made from long-spined sea urchins on plants.

"Hopefully soon you'll be able to buy sea urchin fertiliser for the home garden or a commercial industry to put on crops," Dr Keane says.

The long-spined sea urchin is a voracious ocean pest that is decimating reefs along Tasmania's east coast.

It has become a huge threat to the state's multi-million-dollar abalone and rock lobster industries after munching its way through habitat.

To stem the tide, a state-government-subsidised fishery catches the urchins for their roe, but 95 per cent of the urchin goes waste; that was until now.

Turning a feral pest into fertiliser

Tasmanian agricultural scientist Harriet Walker says the nutrient properties of the urchin waste are ideal for the home garden and broadscale agriculture.

"It is rich in a lot of important plant micronutrients, such as boron and zinc, and is relatively high in nitrogen, which tends to be the most limiting nutrient when it comes to plant growth," Ms Walker says.

"It's full of calcium, and for that reason we see its potential as an agricultural liming product."

Researchers from the Tasmanian Institute of Agriculture are being funded by the Fisheries Research and Development Corporation to test urchin fertiliser on plant growth.

The scientists are testing it on sunflowers and hope to take the trials to broadscale agriculture later this year.

"As we're applying more fertiliser we're seeing increased plant growth and we're also seeing the sunflowers themselves are producing the flower heads faster than our control fertiliser," Ms Walker says.

"We are really excited about the potential of this product and hope it will provide a great example of how, by thinking slightly outside of the box, we can reduce waste and promote a circular economy."

Author and gardener Hannah Maloney is keen to have this pest in her veggie patch.

"Those minerals are inaccessible and hard to get in some of our soils so we need to bring them in. If we can bring them in from local areas that's the ideal," Ms Maloney says.

A licence to grow

For True South Seafood's Simon Owen the urchin is close to bringing his processing factory another income stream.

As a major abalone processor and exporter, the urchin was initially a threat to business.

The company set itself up to process 450 tonne of urchin for roe a year but needed to find a use for the waste.

"The problem was that 95 per cent of the total tonnage of urchins processed each year was waste," Mr Owen says.