White spot disease

White spot disease is a highly contagious viral infection that affects crustaceans.

​​​​​​​​​​​​​​​​​​​​Current situation

Photo showing prawns with White Spot Disease lesions Photo showing prawns with White Spot Disease lesions Photos courtesy of Queensland Department of Agriculture and Fisheries - White Spot Disease lesions

The fallow period for the affected prawn farms, under the Commonwealth Grant Agreement, finished on 31 May 2018. Some prawn farms along the Logan River are preparing to return to production in spring this year. Biosecurity Queensland will work closely with them to monitor production as it progresses.

The farmers will also receive technical advice on a range of enhanced biosecurity measures that will need to be applied throughout their production cycle. This aims to reduce the risk of a disease recurrence.

These measures include finalising and implementing an on-farm biosecurity plan to manage disease risks, and to having systems in place so any suspect signs of disease can be reported immediately.

Brood stock sourced from the Northern Territory and far north Queensland are subject to testing for a range of diseases prior to their progeny being released for grow-out.

The national Aquatic Consultative Committee on Emergency Animal Diseases continues to meet, and provides technical and expert advice to Queensland.

Surveillance

Biosecurity Queensland has resumed White spot disease surveillance in the Logan and Brisbane Rivers and within the Moreton Bay region. The results for this surveillance are expected in October.

All jurisdictions including the Department of Agriculture and Water Resources which is responsible for Commonwealth prawn fisheries, have collected samples as part of the national surveillance program. To date, all samples that have been collected and tested within other states and territories, have returned negative results.

The national two-year surveillance program is relevant to demonstrate that other areas in Australia remain disease free.

​Recreational and commercial fishers

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.

Tips to keep your favourite fishing spot disease free

Photo showing prawns with White Spot Disease lesionsPhoto courtesy of NSW DPI
  • If you use prawns, marine worms or yabbies as bait, make sure you always use wild-caught. Get it from a trusted supplier or catch your own in your local area.
  • Prawns and other seafood purchased from the supermarket or fishmonger are meant for human consumption and must not be used as bait. Although safe for human consumption, they have the potential to spread diseases when used as bait.
  • Uncooked prawn waste could introduce diseases into our waterways if not disposed of properly. Put all unwanted bait and seafood in the bin.
  • Keep your fishing gear, boat and trailer clean. Make sure that any 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. 

See the NSW DPI fact sheet: Make ‘clean’ part of your routine [PDF]

Queensland white spot disease movement restrictions video featuring fishing guru Scott Hillier

Queensland’s ‘Be a mate, check your bait ’ campaign featuring Andrew Symonds

Movement restrictions

Photo showing prawns with White Spot Disease lesionsPhotos courtesy of Queensland Department of Agriculture and Fisheries - White spot disease movement restrictions

The Movement Restriction Area in Queensland will remain in place, and the Queensland Department of Agriculture and Fisheries (QDAF) does not anticipate any change to this in the foreseeable future. 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, yabbies and marine worms out of the white spot restricted area that extends from Caloundra to the NSW border and west to Ipswich.

To provide a level of protection to prawn farms, QDAF has introduced fishing restrictions within 100 metres of the inlet and outlet channels, and in all prawn farm drainage channels in the Logan River region.

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. They can now be moved out of the restricted 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 QDAF website.

Restrictions that apply in other states and territories

The NSW Department of Primary Industry has issued two Importation Orders​

The Western Australia Department of Primary Industries and Regional Development has Import requirements in place. 

Primary Industries and Regions South Australia has restrictions that apply to bait/berley​

How to report white spot disease

White spot disease can only be diagnosed through appropriate laboratory testing. Infected prawns and yabbies may not display any symptoms.  In some cases, white spots can appear on them because of freezer burn or bacterial and fungal infections.

If you suspect that you have purchased prawns with white spot disease symptoms, do not use them or throw them away. Keep them refrigerated and phone the Emergency Animal Disease Watch Hotline from anywhere in Australia on 1800 675 888. You will be connected to your local department of primary industries or fisheries, and provided with further advice.

Information for prawn farmers

The information below provides advice on how to prevent a disease incursion on your farm.

On-farm biosecurity

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 and Water Resources 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).

Download the Aquaculture Farm Biosecurity Plan: generic guidelines and template

Disease management

All aquaculture farms should have a Disease Management Plan including standard operating procedures that can be implemented in the event of a disease outbreak.

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

Photo showing prawns with White Spot Disease lesions Photo courtesy of the Queensland Department of Agriculture and Fisheries

Photo showing prawns with White Spot Disease lesions Photo 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.

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.

This is why it is critical that people fishing in Australia’s waterways do not use prawns intended for human consumption as bait.

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.

Australia is one of the few countries in the world with a prawn farming industry that has remained free of white spot disease.

The Department of Agriculture and Water Resources has more information:

White spot disease - Aquatic Animal Diseases Significant to Australia: Identification Field Guide

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 will 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.

Photo showing prawns with White Spot Disease lesionsPhoto showing prawn with salt crystallisation
Photos courtesy of Queensland Department of Agriculture and Fisheries -
White Spot Disease lesions and prawn with salt crystallisation

It is unlikely that white spot disease could be detected by consumers in imported prawns. The disease is not visible in prawns that do not have a head or shell. Prawns imported to Australia are required to be de-headed, and most that are supplied to retail outlets are de-shelled.

Review of import conditions

The Australian Government Department of Agriculture and Water Resources put in place enhanced import conditions in July 2017 to allow for the safe trade in prawns and prawn products to Australia.

The department has indicated that if the biosecurity risks for these products change, then the enhanced import conditions may be amended to ensure that Australia’s appropriate level of protection continues to be met.

On 27 July 2018, the department released a Biosecurity Advice outlining the new enhanced import conditions for breaded, battered and crumbed (BBC) prawns.

From 28 September 2018, all imported BBC prawns will need an additional par-cooking step during processing to ensure the coating solidifies and adheres to the prawn.

The department is also undertaking a comprehensive review of the biosecurity risks and import conditions for prawns and prawn products imported for human consumption. This review was announced by the Director of Biosecurity in May 2017. The first round of stakeholder consultation closed on 2 July 2018. The department is currently considering submissions provided in preparing the draft report.  If you would like further information on the review of import conditions for prawns, contact the department by emailing: Prawn review.

Background

Disease in prawn farms

Disease signs were noticed on the first farm on 22 November 2016. Queensland’s Biosecurity Sciences Laboratory detected white spot syndrome virus on 30 November. Samples were also sent to the Australian Animal Health Laboratory (AAHL) in Geelong, and it confirmed white spot disease on 1 December. AAHL confirmed the second property as being infected on 6 December.

The third property, along with six samples from the Logan River were confirmed positive on 8 December. The fourth property was confirmed infected on 14 December, the fifth on 29 December 2016, the sixth property on 3 February 2017. The seventh farm was confirmed infected on 13 February 2017.

Impact on the prawn industry

The farmed prawn industry in Queensland is worth approximately $87 million annually. These response activities also have national importance. The gross value of prawn production in Australia in 2015-16 was worth $413 million, and in 2015, employed 5 000 people.

More information

Find out about interstate movement conditions and other white spot disease information that relates to your state or territory:

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