Prawn hepatopancreatitis

Biosecurity Queensland is asking all prawn farmers to monitor their stock and report any health issues to Biosecurity Queensland on 13 25 23.

Biosecurity Queensland is investigating prawn health issues observed on three prawn farms in the Bundaberg area. This follows similar events in a prawn farm in the Cardwell area during 2015.

Australia has notified the World Organisation for Animal Health (OIE) of the detection of hepatopancreatitis, an emerging disease in farmed tiger prawns. At this stage the disease has not been reported in any other prawn species.

Prawn samples tested by Biosecurity Queensland have identified a bacterial agent as the potential cause of the prawn disease. The disease shows similarities to acute hepatopancreatic necrosis disease (AHPND), but evidence to date involves a different species of bacteria to that which normally defines AHPND.

Biosecurity Queensland and Fisheries Queensland are conducting an investigation to identify the bacterial species associated with the disease and are working with each of the affected farms to put in place appropriate biosecurity management strategies.

Broader engagement is also occurring across the prawn farming industry to increase awareness of the disease and of appropriate management strategies that should be put in place in case of future detections.

There are no human health issues associated with the consumption of cooked or frozen prawns.

Detecting and reporting the disease

Biosecurity Queensland is asking all prawn farmers to monitor their stock and report any health issues to Biosecurity Queensland on 13 25 23.

Be vigilant in monitoring your ponds for health or low survival. Signs to look for include:

  • prawns coming to the edge or water surface of the pond, tank or cage
  • prawns demonstrating unusual swimming patterns
  • reduced feeding and failure to thrive
  • unusual changes in the physical appearance of the animal such as red or black colouration, ulcers, erosion or mouldy growth on shell, or fouling of gills
  • increased bird activity around ponds.

Biosecurity Queensland offers a free laboratory diagnostic service when investigating a disease or mortality incident on your farm.

In the event a disease condition is identified, Biosecurity Queensland will provide advice on an appropriate course of action (e.g. site inspection, sample collection).

Managing a disease outbreak

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

Your disease management plan should be immediately implemented if you suspect a disease outbreak to limit the spread of the disease within your farm and to protect healthy animals. Prawns that are suspected of being diseased must not be moved unless they have been cooked or frozen. All live suspect prawns must remain on your farm until you have received advice and permission to move them from Biosecurity Queensland.

As well as advising Biosecurity Queensland of a disease, you should:

  • isolate any animals showing signs of disease or infestation in separate ponds and tanks
  • stop water flow from these ponds into the surrounding environment
  • quarantine all equipment from other ponds and tanks
  • prevent animals, vehicles and humans from spreading disease through the farm
  • implement strategies to reduce birds from spreading disease within the farm in accordance with the Australian Prawn Farmers Association (APFA) Environmental Code Of Practice. This should be non-destructive methods such as netting or use of bird scaring devices, unless you have a permit for other methods.
  • look after healthy animals each day before you have any contact with sick ones
  • collect specimens of affected aquatic animals for laboratory examination
  • safely dispose of diseased and dead animals and effluent water.

Emergency harvest and decontamination are options that may be considered appropriate to manage the disease in an established aquaculture farm, or minimise the risk of spread to other farms and the environment.

In the event of a serious disease outbreak, Biosecurity Queensland and Fisheries Queensland will work with affected farms to manage the risk particular to the situation while offering as much flexibility as possible to minimise impacts on your business.