White spot disease

A prawn shell fragment from a prawn affected by white spot disease

A whole prawn affected by white spot disease

White spot disease is a highly contagious viral infection that affects crustaceans such as prawns, yabbies and crabs. When found in high-intensity production areas, such as prawn farms, white spot disease results in the rapid mortality of prawns.

The virus that causes white spot disease does not pose a risk to food safety or human health, so prawns are safe to eat.

Cause

White spot syndrome virus

Description

Symptoms in prawns may include:

loose shells
white spots (0.5–2.0mm in diameter) on the inner shell surface
pink to red discolouration
unusual mortality or swimming behaviour
congregation at the water's edge.

Crabs and other crustaceans:

can be carriers
may not display any visible signs.

Note: This disease is not the same as white spot found in aquarium fish.

Distribution

Widespread throughout prawn farming regions in Asia.
Established in prawns farmed in the Americas, where it has caused severe losses on prawn farms.

Detection in Australia

The disease was first detected in Australia in 2016 on 7 prawn farms in the Logan River region of South East Queensland. It has since been detected in wild-caught prawns and crabs in surrounding waterways, including Moreton Bay and the Redcliffe Peninsula.

Recent detections in northern NSW prawn facilities and wild populations of school prawns have led to temporary restrictions on the movement of uncooked prawns from the Clarence River, Richmond River and Evans Head control zones.

Genetic testing showed the strain of virus detected in NSW is different from all the Queensland samples.

Affected animals

Decapod crustaceans, like prawns, lobsters, crabs, yabbies

Impacts

Economic

White spot disease poses a major biosecurity threat to Australia's prawn aquaculture industry. An outbreak can also impact commercial trawler operations and disrupt trade.

A white spot disease outbreak in South East Queensland shut down production on 7 farms for nearly 2 years.

The Queensland prawn farming industry is valued at around $210 million annually (2023–2024 Aquaculture production summary report).

The long-term impact of white spot disease on wild prawn populations is still being studied, as there is limited international evidence on its effects in natural environments.

How it is spread

The disease is primarily spread through the movement of infected animals or contaminated water.

Birds that feed on and move infected animals can spread the disease.
Marine worms have been implicated as potential carriers of the disease overseas, although negative results from extensive testing of worms in Moreton Bay indicate that the risk is extremely low.
Finfish are not affected by the disease and are not a carrier of the disease.

Prevent the spread

Buy bait from trusted sources.
- Always purchase prawns and bait from bait suppliers or service stations.
- Do not use raw supermarket prawns as bait as they may carry diseases, even if they are Australian.
- Watching this video about buying bait from trusted sources.
Cook to kill the virus.
- Cooking prawns in boiling water for 3.5 to 4.5 minutes (depending on size) will inactivate the white spot virus. Freezing does not kill the virus.
Catch your own bait.
- You can catch your own prawns, yabbies or marine worms, but remember, if caught in the white spot restricted area in South East Queensland, these species must be cooked before being taken out of the area.
- Always check the latest biosecurity maps.
- Watch these videos about catching your own bait yabbies and catching your own bait pipis.
Dispose of bait properly.
- Place unwanted bait or seafood in the bin. Never discard it in Queensland waterways.
Do your part.
- With Australian prawns only meeting 40% of consumer demand, imports are necessary—but this increases disease risks.
- Everyone has a role to play in protecting our environment by using bait responsibly and following biosecurity rules.

Control

Movement restrictions are in place. You must not move crustaceans out of the white spot disease restricted area (PDF, 1.47MB). Find out more about white spot disease and:
Crabs, lobsters and bugs are not subject to movement restrictions, as they are sold for consumption only and are unlikely to be returned to natural waterways.
Fishing is prohibited within 100 metres of water intake and outlet channels near land-based prawn farms in parts of the Gold Coast (e.g. Coomera, Alberton, Jacobs Well, Pimpama).
Destruction, disposal and decontamination procedures for infected prawn premises.
Bird mitigation for infected prawn premises.
Crab control for infected prawn premises.