Virus strikes SA abalone, PIRSA monitors spread

Ocean users in the South-East have been asked to exercise extra caution following the spread of abalone viral ganglioneuritis (AVG) in South Australian waters for the first time.

The Department of Primary Industries and Regions (PIRSA) said AVG has been confirmed in wild abalone in waters south of Port MacDonnell, and restrictions are now in place from the Southend to the South Australian-Victorian border in the east.

“AVG is caused by a herpes virus specific to abalone. It affects their nervous system, causing weakness and eventually death,” the department told this newspaper [Naracoorte Community News].

“The disease can cause high mortalities in both farmed and wild abalone populations. Species known to be susceptible to AVG in Australia are greenlip abalone (Haliotis laevigata), blacklip abalone (Haliotis rubra) and hybrids of these two species.

“AVG can spread through the water from infected abalone or abalone products, fishing equipment, or people who have come into contact with it.”

PIRSA eased some of the restrictions in place on March 14.

The use of anchors and the recommencement of rock lobster fishing is permitted under an exemption in the Southern Rock Lobster Zone, including the control area, under specific conditions.

When asked about the chances of AVG spreading to waters in Kingston and Robe, PIRSA said surveillance was being undertaken to determine the risk of further spread.

“The Incident Management Team is presently undertaking surveillance throughout the Control Area and Buffer Zone with the assistance of the abalone commercial industry.

“Once the results of the surveillance are known, we will be better placed to understand the risk of further spread.

“The virus is known to move naturally through the water column to adjoining reefs. However, this type of spread varies greatly depending on the habitat, water currents, and the amount of sick abalone.

“Human-assisted movement presents the greatest risk of rapid, long-distance spread, which is why it is critical that everyone follows the restrictions that are in place.”

PIRSA said AVG can result in up to 90 percent mortality of abalone on a reef.

“Following a mortality event of that scale, local populations of abalone can take many years to recover to existing population levels. AVG has no known effects on human health.”

“The highest risk of AVG spread is through the water, from infected abalone or abalone products – offal, shells, or mucus.

“There is also a risk of AVG spread contaminated through fishing and diving equipment—wetsuits, anchors, rock lobster pots, ropes, rods, and lines.

“People who have come into contact with infected abalone, abalone products, or bottom habitat can also spread AVG.”

AVG was detected in wild abalone at Port MacDonnell, and a control area has been declared within the state’s Southern Abalone Zone.

The virus has been detected at the western end of the original control area, so that area has been extended.

A buffer zone has been established from Southend to the River Murray Mouth to ensure good biosecurity practices are in place to reduce the risk of further spread.

PIRSA has activated a response team dedicated to handling the AVG outbreak. In addition to establishing the control area with restrictions on activities that could cause the spread of AVG, a buffer zone has also been created while further surveillance is undertaken, and to help limit further spread of AVG through human activity, full information is on the PIRSA website.

In the control area, you cannot:

• Fish from the shoreline or boat.
• Anchor for the purposes of fishing activities.
• Use commercial fishing or abalone equipment.
• Use hoop nets, bait traps, hauling nets or abalone levers for recreational fishing.
• Collect any abalone, rock lobsters, sea urchins, or other aquatic invertebrates, whether live or dead.

The public can help reduce the spread of AVG by doing the following:

• Check all vessels, fishing, diving, and surfing equipment, remove anything including, water, sand, or seaweed, and check your catch for signs of illness.
• Clean boats at home or at a commercial car wash, and wash your wetsuits, fishing, and diving equipment with fresh, soapy water.
• And dry all boating, fishing, and diving equipment completely before heading out into the water again.

Naracoorte Community News Editor’s note: This is a developing situation that is being monitored by PIRSA. Some details may have changed when this edition went to press.

This article appeared in the Naracoorte Community News.