A deadly virus has struck abalone at key sites in SA. 

A lethal outbreak of abalone viral ganglioneuritis has been reported at Port MacDonnell, leading to strict fishing restrictions in South Australia's south-east. 

The disease, which has a mortality rate of up to 90 per cent, affects the nervous system of abalone, causing significant fatalities among the mollusc population.

The presence of the virus was confirmed last week after a commercial fisher discovered dead and dying abalone at Breaksea Reef. 

The Department of Primary Industries and Regions (PIRSA) received thirty samples, which tested positive for the virus, marking the first occurrence of the disease in South Australia.

A control zone has been established, spanning from Nene Valley to the Victorian border, extending approximately 10km out to sea, to prevent the spread of the virus. 

This zone prohibits all fishing activities, impacting both recreational and commercial sectors.

The disease not only threatens the abalone industry but also puts pressure on other local fisheries, including the rock lobster fleet. 

To mitigate the spread, PIRSA advises thorough cleaning of vessels and equipment. The restrictions have also affected the amateur fishing industry, with concerns over the impact on tourism and recreational activities in the region.