In short:

South Australian oyster growers are cautiously optimistic in the wake of last year's harmful algal bloom.

Some producers are facing challenges such as a decrease in stock and an increase in barnacles.

What's next?

The industry is waiting to see if the bloom returns as the water warms.

Oyster growers are cautiously navigating the aftermath of South Australia's harmful algal bloom, nearly 12 months after some harvesting regions reopened.

Simon and Meagan Turner operate out of one of the state's largest growing regions north-west of Adelaide at Franklin Harbour on the Eyre Peninsula.

The area was closed for four months last year, reopening in November.

Now, oysters are healthy and a sense of normalcy is finally returning.

"Dolphins, benthic feeders, they're all coming back in force and that's a fairly good indicator that the bay is coming back," Mr Turner said.

Less stock in the water

Recovery is moving at different speeds across the coastline, but there is one constant across the board: decreased stock.

With closed harvesting areas and an uncertain future this time last year, growers did not input young oysters when they usually would.

"It's probably now that we're going to feel the effects of the algal bloom, as far as production goes … because oysters take about 12 to 15 months to grow," Mr Turner said.

For the Turners, it has resulted in about 40 per cent less stock on hand than normal.

Government support helped shelter the business from major financial losses amidst the worst of the bloom, and since reopening it has been "an extremely good year financially".

"But we're going to seriously feel it now because we just don't have the product in the water," Mr Turner said.

"I think most people will go, well, the bloom started then and it finished then, so we're back on track and off we go. It just doesn't work like that."

Tale of two peninsulas

Across the Spencer Gulf at Stansbury, Steve Bowley has not put new stock in for at least 18 months.

Mr Bowley said an increase in barnacles and dead weed stock has damaged his water infrastructure, while he estimated a $400,000 decline in business value and an increase in mortalities.

"Out of every five dozen [oysters], I reckon I'm getting one dozen that are dead … I certainly haven't seen that in 20-odd years," Mr Bowley said.

"I think what we're seeing is that as the oysters are stressed by the lack of oxygen in the water and these other things, lack of water flow from the barnacle and the weed, then it's the weak ones that die."

Before the bloom, he had been hoping to sell the business and retire.

"Can I get my money back? I don't think I can. I think our business is largely worthless now,"Mr Bowley said.

Waiting for what summer brings

With summer fast approaching and no way of knowing if the harmful algal bloom will return, all eyes are on the water.

"It's kind of hanging over us a bit like the Sword of Damocles in that we're waiting [to see] if the water temperature rises and then it blooms again, what the impact of that is going to be," Mr Bowley said.

"It's discouraging, to say the least."

Despite the uncertainty, South Australian Oyster Growers' Association chair Peter Treloar said the industry felt "relieved".

"There's always ups and downs in the industry, but for the most part there's confidence, there's production occurring, and growers are looking forward to making sales ahead of Christmas," he said.

Like the rest of the state, the Turner family is just happy to be back in the water.

"I believe the ocean flows through our veins as a family … and during the algal bloom it was quite a load mentally to see that taken away from us," Ms Turner said.

"It just feels like a moment where we can finally breathe."