White Spot Disease (WSD), also known as infection with White Spot Syndrome Virus (WSSV), is a highly contagious viral disease of prawns that causes high rates of mortality in affected stock. Other crustaceans can be carriers of the virus, but they are rarely impacted by the disease. WSD poses no threat to human health or food safety.
WSD spread through Asian prawn farming regions rapidly in the 1990’s and also became established in in farmed prawn in the Americas causing widespread losses.
What are the characteristics of White Spot Disease?
- Signs of White Spot Disease in aquaculture within tanks and ponds include:
- rapid onset of mass mortality (80% or more) in farmed penaeid prawns during the grow out period
- cessation of feeding
- aggregations of moribund prawns near the water surface at the edge of the rearing pond or tank
Prawns may display:
- a loose carapace
- high degrees of colour variation, with a predominance of darkened (red-brown or pink) body surface and appendages
- white calcium deposits embedded in the shell, causing white spots 0.5 – 3.0 mm in diameter
Please note, that like any aquatic disease, diagnosis cannot be made without appropriate laboratory testing. For information on how to submit samples for diagnosis contact NSW DPI Aquatic Biosecurity on the numbers given below.
For further information on the characteristics of white spot disease see:
Outbreak of white spot disease in Queensland – December 2016
In December 2016 White Spot Disease was detected in farmed prawns in south east Queensland. For further details of the outbreak see www.outbreak.gov.au/.
There is no evidence of White Spot Disease in NSW prawn farms or in wild caught prawns.
What is NSW government doing to protect NSW aquaculture and wild stocks from White Spot Disease?
NSW Department of Primary Industries (DPI) is working together with other jurisdictions (states, territories and the Commonwealth) to help minimise the risk of White Spot Disease spreading.
DPI has established an importation order (PDF, 874.27 KB) that places restriction on the importation into NSW of any uncooked decapod crustaceans or polychaete worms from a designated area encompassing all affected areas in south east Queensland.
White Spot Disease is a declared disease under Schedule 6B of the Fisheries Management Act 1994. This includes a duty to report the presence or suspected presence of white spot disease at any place.
What you can do to help prevent the spread of White Spot Disease
Information for members of the public
- be aware of bait showing signs of White Spot Disease and if concerned it may be diseased, do not use the bait and instead contact DPI Aquatic Biosecurity on the numbers provided below.
- Make ‘clean’ part of your routine
Information for prawn farmers
- follow your permit conditions, including those relating to biosecurity
- report any unusual mortalities or suspicions of White Spot Disease to a fisheries officer as soon as possible, and within 24 hours
- if you haven’t already done so, prepare a Biosecurity Plan, both to minimise the risks of aquatic disease entering your property and of it spreading if it does enter
- use separate equipment for different ponds or tanks throughout your property if possible
- disinfect and decontaminate equipment between use in different areas of your farm
- keep good records of stock movements, for both incoming and outgoing stock and for movements to different areas within the farm
- minimise unnecessary visitors to your production areas of your farm and find out where delivery trucks and other visitors have previously visited before accepting them on site
Information for seafood processors and bait suppliers
- be aware of the importation order currently in place on uncooked prawns originating from within a 10 km radius of the first infected farm on the Logan River in south east Queensland
- ensure that you are not importing uncooked prawns (for bait or human consumption) into NSW from within the prohibited areas
- please note that cooked prawns for human consumption are excluded from the importation order and that White Spot Disease poses no threat to human health or food safety.
Report any signs of unusual mortality or other suspicions of white spot disease to
- NSW DPI Aquatic Biosecurity on (02) 4982 1232
- On the Aquatic Pest & Disease 24 hour recorded reporting line: (02) 4916 3877
- Or via email firstname.lastname@example.org