The South Australian government is monitoring an alarming resurgence in algal bloom activity in two areas of its coastline.

South Australian Research and Development Institute executive director Professor Mike Steer said spots in the Yorke Peninsula and Kangaroo Island regions were being watched, although he remained “cautiously optimistic” about the toxic ocean bloom’s lessening impact.

“It’s important that we maintain monitoring and surveillance through summer and into autumn to make sure that we’re on top of it,” Steer said on Wednesday.

“The other thing we can say is that, if you compare the data now to where we were a few months ago, it has significantly reduced, which is some form of positive. But we just need to be careful in our interpretation.”

Steer said the algal bloom had been relatively active in recent weeks in around the south-western end of the Yorke Peninsula, around Innes National Park, extending from around Chinamans Hat Island through to Browns Beach and around Corny Point.

While activity in that region was increasing, “the concentration of those cells is reducing, which is good to see”, he said.

Steer said that on Kangaroo Island, SARDI was monitoring the bloom as it moved further west to the north of the island around Stokes Bay, “but even there it’s diminishing”.

He warned that foaming events and dead fish washing up would continue on Kangaroo Island and the Yorke Peninsula.

“We will see dead fish, particularly any gill-breathing organism, are negatively impacted by the algal bloom,” Steer said.

“The other thing that the algae does is, when it dies, it decomposes, it draws the oxygen out of the water. So, we will see fish in those impacted areas wash up.”

Foam from SA’s toxic algal bloom on the Yorke Peninsula. Photos: Facebook/Andy Smyth

Steer said foaming would be most noticeable around the Yorke Peninsula “because it’s a high wave energy area”.

“That, coupled with onshore winds, [means] you’ll get that churning organic material, the algal species plus a whole heap of other organic material that’s naturally in there, and that’ll churn up and wash ashore,” he said.

Steer urged people to follow the latest health advice, which includes avoiding areas with discoloured water or foamy conditions if susceptible to irritation.

Asked about concerns that offshore dredging along the SA coastline had contributed to the algal bloom, Steer said that it was more likely “large ecosystem drivers rather than any point bits of activity along the coast”.

“We’re looking at significant environmental and ecological events like the record-breaking Murray River flood, like our big system-wide upwelling seasons along the coast and also the unprecedented heatwave that we hadn’t experienced for more than 40 years,” he said.

“These are really big drivers that are most likely operating, collectively, in combination to stimulate this harmful algal bloom. Little things, like pockets of activity around the coast, would have a negligible impact, if any at all.”

In relation to human health impacts, Steer said that “in areas where there’s no Karenia or relatively low or natural levels, there’s a lot of other things in the water that can create itchy skin”.

“Being a surfer myself, at times, you sometimes come out and feel a little bit crusty with the saltwater, or there might be blue bottles in the water.”

Latest testing results from the week beginning on December 28 showed that 20 of 21 metropolitan onshore sites in SA had no or low levels of Karenia.

In regional areas, testing showed zero or low levels of Karenia across much of the Eyre Peninsula, Yorke Peninsula and Fleurieu Peninsula. Elevated levels were detected at Whyalla Jetty (14,000 cells a litre) and Emu Bay Jetty on Kangaroo Island (27,820 cells a litre).

Republished from InDaily