As dawn breaks in Port Lincoln on South Australia’s Eyre Peninsula, Mark Andrews watches from the town’s marina as mussel farmers bring in their catch.

Yumbah Mussel Holdings harvests up to 40 tonnes of native blue mussels a week from the surrounding sheltered waters of Boston and Proper bays, with its harvesting sites up to 22 kilometres away.

Mr Andrews is the company’s general manager of mussel operations and said their team contributes to about 60 per cent of Australia’s mussel production, with an annual turnover of $20 million.

“I moved here for one reason and that was the natural spat,” he said.

“Port Lincoln is so unique, the number of natural spat larvae that spawn and settle between May and September every year.”

Mark Andrews said his mussel growing business is at risk with the proposal of a desalination plant to be built in Port Lincoln.(ABC News: Brant Cumming)

The company’s success can be attributed to natural larvae floating in surrounding protected bays.

But he said his business was at risk from a proposed desalination plant to be built at Billy Lights Point in Port Lincoln.

Its intake and discharge pipes are expected to reach out into the surrounding waters of Boston and Proper bays that the business relies on.

“My main concern about a desalination plant that takes up 5 gigalitres of water per year — [a figure] they’re talking initially … a percentage of that spat will go into the intake,” he said.

“What percentage? Well nobody can determine that.”

SA water plans to build its infrastrucutre at Billy Lights Point, close to Port Lincoln’s marina. (ABC News: Brant Cumming)

‘Precautionary principle’

The company’s operations manager Andy Dyer shares Mr Andrew’s concerns.

He checks on the crews who harvest mussels from one of the company’s 24 sites.

Andy Dyer said the precautionary principle is often considered by those who work in the aquaculture industry.(ABC News: Brant Cumming)

The prized mussel spat settles and grows on ropes left out at sea.

Once the product is harvested, it is shipped to Adelaide on the same night, then interstate and also onto international destinations like Singapore, Hong Kong, and Dubai.

Mr Dyer and his wife launched the mussel farming industry in Port Lincoln more than 25 years ago.

“We established that there were natural mussels in the bay that were attaching to yacht club moorings, they were attaching to some of the early tuna farming cages, so we decided that we would take the plunge and try and develop a mussel industry here,” he said.

“Today, it’s been quite a success story for Port Lincoln.”

He is concerned about SA Water’s proposed project being placed so close to a thriving aquaculture zone.

“We can’t say whether a desalination plant is going to affect the mussel settlement — but neither can they. From an aquaculture perspective we always have to do things under the precautionary principle,” Mr Dyer said.

Natural mussel spat settles on ropes that are placed in the sheltered waters surrounding Port Lincoln.(ABC News: Brant Cumming)

Marine scientist Paul McShane has been consulting Yumbah on SA Water’s latest plans for a desal plant.

He said the unknowns about mussel larvae movement lead to a risk that can’t be quantified.

“On the smaller scale, in terms of the proximity of the desal plant to the mussel growing area, we don’t know what the impact will be. There’s certainly going to be an impact but we don’t what the level of it is,” Professor McShane said.

Community voices concerns

Port Lincoln Deputy Mayor Jack Ritchie said council does not support the project’s location and many concerns from the community have been communicated to council.

Jack Ritchie said council does not support SA Water’s proposed location for a desalination plant.(Supplied: Port Lincoln Council)

“Their concerns are the risk to the aquaculture industry that is based here in the bay,” Mr Ritchie said.

“What those concerns [are] about [is] ‘are we putting an industry that is a sustainable food source at risk?'”

Barngarla traditional owners of the region have also voiced opposition to the project.

Main source running dry

But time is running out for SA Water to provide reliable drinking water for the Eyre Peninsula.

Water supply issues were identified from the late 2000s.

Currently, Port Lincoln heavily relies on the Uley South Basin for its water; about 75 per cent of the region’s water is drawn from the underground source.

Water is pumped from the underground source, the Uley Basin and stored in large water tanks close to Port Lincoln’s town centre.(ABC News)

Water is drawn up from the basin through pipes and pumped into tanks that store water for the residents.

The region’s landscape board has warned the basin will be depleted by next year if current extraction rates continue, with increased salinity already detected in some of the production bores.

The region’s landscape board has also recently announced it was urgently reviewing its water allocation plan.

Which is why SA Water argues the plans for the desalination plant should go ahead.

Need for security

It would take around a year to build and if the project is delayed, SA Water said it would have to consider staged water restrictions.

SA Water’s Peter Seltsikas said the department is seeking to build the climate-independent infrastructure to protect the water security of the Eyre Peninsula.

“To ensure that the customers of today have water, but also so we can continue to support the customers of the future,” Mr Seltsikas said.

He said Port Lincoln’s proposed desalination plant would have minimal risk to the mussel industry.

“[From] the studies we’ve done, there is less than 0.1 per cent chance of mussel spat in the bay being entrained within the intake of the desalination plant,” he said.

SA Water’s Peter Seltsikas said a climate independent desalination plant is needed for the region.(ABC News: Brant Cumming)

But the mussel industry is wary of the studies carried out by SA Water and the state’s Research and Development Institute, saying the risk could not entirely be ruled out and the plans have been rushed through now the Uley Basin is in stress.

Mark Andrews is well aware of the water security issues but said alternatives should have been considered earlier.

“[SA Water said to me] ‘Mark, if you hold this process up we’re going to have to put water restrictions on the lower Eyre Peninsula’. Well it’s not my fault,” Mr Andrews said.

“I’ve been around doing my thing, you’ve been around for a long time — a lot longer looking for water security and locations before now. So what have you been doing all this time?”

The company has an annual turnover of $20 million.(ABC News: Brant Cumming)

SA Water said it had already considered more than 20 sites in the region.

“We have been through an extensive process of review, and we’re very focused on delivering a desalination plant as soon as we possibly can to ensure the water security of the Eyre Peninsula,” Mr Seltsikas said.

Mr Andrews said he wanted to protect the company and its valued workers.

“I set up this business employing 76 people and I’ve invested a lot of money [as] the leading shellfish mussel farmer, grower marketer in Australia,” he said.

“We’re leading in all areas of new product development and everything else. I can’t afford any risk to my business.”

A development application for the desalination plant is expected to be submitted by mid-year.

Watch ABC TV’s Landline at 12:30pm on Sunday or on ABC iview.