White spot disease
White spot disease is a highly contagious viral infection that affects crustaceans. The disease is caused by white spot syndrome virus (WSSV).
White spot disease was first detected in South East Queensland in December 2016.
Seven prawn farms on the Logan River were affected from late 2016 to early 2017. The virus was also first detected in wild populations of crustaceans, such as prawns and crabs in Moreton Bay in early 2017.
Prawn farmers on the Logan River have applied a range of enhanced biosecurity measures throughout their production cycle to reduce the risk of a disease recurrence.
There have been no detections or evidence of the virus in the Logan River prawn farms during the 2020/21 production season. Four farms have returned to production.
White spot syndrome virus has established in some populations of wild crustaceans within the Queensland Movement Regulated Area (MRA). All areas of Australia, outside of the MRA, remain free from the virus.
Movement and fishing restrictions remain in place in the MRA.
National arrangements of ongoing surveillance including targeted surveillance for the boundaries of the MRA will continue until 2022 to provide confidence regarding containment of WSSV to the MRA.
Government response to white spot disease
The Movement Regulated Area, which includes the Logan River area and Moreton Bay, was established in early 2017 to prevent movement of crustaceans from the area, unless they are cooked or treated in a way that will de-activate the virus.
This has prevented spread of the virus to other locations in Queensland and other states and territories.
These measures were developed based on their effectiveness, cost, business impact, and feasibility. The movement restrictions will remain in place.
The Queensland Department of Agriculture and Fisheries (QDAF) has continued to work closely with the Logan River prawn farms as they have returned to production.
The national Aquatic Consultative Committee on Emergency Animal Diseases (Aquatic CCEAD) has met regularly during the response to provide technical advice and national coordination for response activities.
There is now national agreement that this disease has established in Moreton Bay and as such the emergency response has transitioned to ongoing containment and management.
Responsibility for ongoing national coordination of the virus will be transferred to the Animal Health Committee.
The Aquatic CCEAD will reconvene as required for any future WSSV incidents.
A national surveillance program for white spot syndrome virus commenced in 2017. The surveillance program was designed to ensure consistency with international standards.
The surveillance program has demonstrated freedom from the virus in all areas of Australia outside the MRA. However, it demonstrated seasonal occurrence of WSSV in species of wild crustaceans within the MRA since March 2017.
Ongoing surveillance will continue to confirm that WSSV remains contained to the MRA and to maintain WSSV zone freedom for all other areas of Australia in accordance with OIE standards.
The surveillance includes passive surveillance and reporting requirements in all jurisdictions and targeted surveillance at locations at the northern and southern boundaries of the MRA.
Keep Australia's fishing spots free from disease
Everyone who uses our waterways has a role in keeping them free from disease. Regardless of where you are in Australia you need to take some simple steps to prevent the spread of aquatic diseases or the transfer of marine pests.
Diseases and pests that affect aquatic animals can easily spread between waterways by the movement of contaminated bait and fishing equipment.
Disease outbreaks can cause major social and economic damage to Australia’s seafood industries.
Be aware of fishing restrictions that are in place within 100 metres of the inlet and outlet channels, and in all prawn farm drainage channels in the Logan River region.
Tips to keep your favourite fishing spot disease free
- When you are selecting your bait, use local and reputable bait shops or source your own bait from local waterways.
- Do not use seafood meant for human consumption as bait.
- Make sure you put all unwanted seafood in a rubbish bin, not in the ocean or waterways.
- Keep your fishing gear, boat and trailer clean. Make sure that any bait, debris and seaweed is removed. In particular, check wheel arches on trailers, boat propellers, fishing tackle and footwear.
- Use soapy water to clean your boat and trailer, fishing rods and other equipment, and allow them to dry completely before using them at another location, even if it is on the same day.
Movement Restrictions remains in place in South East Queensland.
These movement restrictions are to contain white spot disease and prevent new outbreaks.
The restrictions prohibit the movement of high-risk animals such as prawns, worms and yabbies out of the Movement Regulated Area that extends from Caloundra to the NSW border and west to Ipswich.
An exemption exists for low-risk species: spanner crabs, three spotted crabs, blue swimmer crabs, mud crabs, red champagne lobster, slipper lobster, tropical rock lobster, red claw and bugs.
These species can now be moved out of the Movement Regulated Area raw, however anyone wishing to move these species out of Queensland must check the importation requirements of the destination state before doing so.
The movement restrictions do not apply to molluscs (oysters and mussels).
To find out more about the current movement restrictions in Queensland and to download the map, see the Department of Agriculture and Fisheries White spot information guide.
Restrictions that apply in other states and territories
Before importing seafood product from the Movement Regulated Area to other states or territories, check for import restrictions.
- New South Wales: The NSW Department of Primary Industry
- Western Australia: Department of Primary Industries and Regional Development
- South Australia: Department of Primary Industries and Regions
Information for prawn farmers
The information below provides advice on how to prevent a disease incursion on your farm.
Prawn farmers need to ensure appropriate biosecurity measures are in place on their farm which includes sourcing disease free stock and animal feed.
Make sure livestock, water, visitors and staff, and equipment that are coming onto, and leaving the farm are clean. Equipment and footwear should be disinfected in addition to being cleaned.
The Department of Agriculture, Water and the Environment offers a free guide to help farmers develop biosecurity plans. This template can be easily adapted to your specific aquaculture sector (for example, prawn or abalone farming) or for specific production systems (for example, recirculation finfish aquaculture).
All aquaculture farms should have a Disease Management Plan including standard operating procedures that can be implemented in the event of a disease outbreak.
If you suspect disease on your farm, phone the Emergency Animal Disease Watch Hotline from anywhere in Australia on 1800 675 888.
About white spot disease
White spot disease is a highly contagious viral disease of decapod crustaceans including prawns, crabs, yabbies and lobsters. The disease is caused by white spot syndrome virus.
White spot disease - Aquatic Animal Diseases Significant to Australia: Identification Field Guide
How to identify white spot disease
Photos courtesy of the Queensland Department of Agriculture and Fisheries
Prawns with white spot disease may have a loose shell with numerous white spots (0.5-2.0 mm in diameter) on the inside surface of the shell and a pink to red discolouration.
More reliable signs to look for include:
- unusual mortality
- prawns coming to the edge or water surface of the pond
- prawns demonstrating unusual swimming patterns
- reduced feeding and failure to thrive.
How the disease can 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.
The disease effect on other species
Fin fish are not affected by the disease and are not a carrier of the disease.
Decapod crustaceans including, but not limited to, prawns, lobsters and crabs are susceptible to the infection. Marine worms are also considered to be carriers of the disease.
The white spot disease detected in south east Queensland is not the same disease that can infect ornamental/aquarium fish. White spot in aquarium fish is a parasitic skin infection and not related to white spot disease.
Where white spot disease is found
White spot disease is widespread throughout prawn farming regions in Asia and the Americas where it has caused severe losses on prawn farms.
Food safety and information for consumers
Consumers should be aware that white spot disease does not pose a threat to human health or food safety.
White spot disease can only be diagnosed through appropriate laboratory testing. Infected prawns and yabbies may not display any symptoms and white spots may appear for a range of reasons including, salt crystallisation, freezer burn and bacterial or fungal infections.
The most common reason you may see white spots on prawns that you have purchased is due to the crystallisation of salt under the shell of the prawn. This is because prawns are frozen quickly in a concentrated saltwater immersion process, during which the prawns pass through a saline brine tank. Some salt is then absorbed by the prawns as they freeze. This salt can crystallise under the shell while the prawns are frozen which causes white mottling to appear under the shell of the prawn. This mottling can be found on the body and head and becomes more noticeable as the prawns defrost.
With white spot disease, prawns are likely to have a loose shell with white spots that are 0.5 to 2 millimetres in diameter on the inside surface of the shell and a pink to red discolouration.
The photos below show the difference between white spots caused by white spot disease and white mottling caused by salt crystallisation.
Photos courtesy of Queensland Department of Agriculture and Fisheries - White Spot Disease lesions and prawn with salt crystallisation
Australia’s import conditions
The Australian Government Department of Agriculture, Water and the Environment continues to monitor and enforce stringent import conditions to manage the biosecurity risk associated with imported prawns and to safeguard our valuable fisheries and aquaculture industries.
Pre-border and border disease testing, retail testing, and working with exporting countries are being undertaken to ensure Australia's import conditions are being met.
The department is undertaking a review of all import conditions and biosecurity risks for prawns to ensure that risk management measures continue to meet Australia's appropriate level of protection. Further information about the review is available on the Department of Agriculture, Water and the Environment website.
Enforcement action will continue to be taken against importers who are found to be deliberately non-compliant with import requirements.
Find out about interstate movement conditions and other white spot disease information that relates to your state or territory:
- Queensland Department of Agriculture and Fisheries
- NSW Department of Primary Industries
- Reporting in NSW:
Aquatic Pest & Disease 24 hour recorded reporting line: (02) 4916 3877 or email Aquatic Pests
- Department of Primary Industries and Regions South Australia
- Department of Fisheries Western Australia
WA FishWatch 24 hour hotline on 1800 815 507
- Department of Agriculture and Food Western Australia (import conditions)
- Northern Territory Government
- Australian Prawn Farmers Association