Growers say this is a different type of algae again from the kind that closed the estuary for several months earlier this year.

Evidently it is a PSP, cell type is Alexandrium, and it has shown a weak sign of toxicity and the good news is that the most recent tests last week shows it is dropping off.

More tests will be conducted this week.

The NSW Food Authority always acts on the side of caution closing the harvest when tests indicate any kind of potential toxicity.

Wagonga has had a reputation of being one of the cleanest estuaries with little or no man-made pollution as its catchment is largely undeveloped.

The earlier algal bloom was thought to have been exacerbated by February flooding possibly washing in extra nutrients, made worse by the recent fires on Gulaga Mountain.