Submitting prawns for lab examination
If you have sick or dying prawns that need to be submitted for examination and diagnosis by a prawn pathologist, follow the instructions below.
- Select 6 or more sick prawns typical of the problem. Similar samples will be needed from each pond if several ponds are affected. If larval or post-larval prawns are affected, please send 60 or more.
- You may send live or preserved prawns.
How to send live prawns
- Place prawns in a thick plastic bag, partly filled with water, and containing air (preferably oxygen).
- Place this bag in a second thick plastic bag in an aquaculture-standard coolite box and attach a specimen advice sheet (PDF, 630KB).
- Contact the laboratory and advise them how and when the prawns are coming.
How to prepare preserved prawns
Use only live, sick prawns for preservation.
Davidson's solution is the preferred preservative for preserving prawns. However, if not available, 10% seawater formalin may be used.
- Glacial acetic acid 115mL
- Formalin (37-40% w/v formaldehyde solution) 220mL
- 95% ethyl alcohol (ethanol) 330mL
- Tap or distilled water 335mL
If there will be a long delay in sending the preserved prawns to the laboratory, replace the Davidson's solution with 50% ethyl alcohol (ethanol) after 24-72 hours.
10% seawater formalin (for marine specimens)
- Formalin (37-40% w/v formaldehyde solution) 100mL
- Seawater 900mL
Prawn specimens may be held in 10% seawater formalin indefinitely.
Always wear gloves and protective eye wear when handling preservatives.
For post-larvae prawns (less than 10mm long), catch them in a plankton net and place directly into the preservative solution (Davidson's solution or 10% seawater formalin).
Prawns over 10mm
For prawns over 10mm long, use the following steps:
- Place prawns in a cool room at below 4°C to chill until insensible. A prawn is insensible if the tail can be easily extended or manipulated and the outer mouthparts can be moved without resistance.
- For juvenile prawns (10-30mm long), cut between the head and the tail (Figure C) and place both pieces into the preservative solution.
- For prawns over 30mm long, use a syringe and a 21-gauge needle to inject the preservative (preferably Davidson's solution) into the prawn to preserve it. Inject 1-2mL preservative into the head (Figure A) and 1-2mL into the tail (Figure B). Cut off the head (Figure C). Cut out a segment of the tail (Figure F). Place all these pieces into the preservative for 24-48 hours.
- Humanely kill the prawn by rapidly cutting through the centreline of the head and tail (Figures D and E) to destroy the nerve centres.
- Ensure that there is 10 times the volume of fixative for each volume of tissue.
- When sending preserved material to the laboratory, pour off the preservative, place prawn specimens into a plastic bag, remove excess air, and seal with heavy packing tape. There should be no free fluid in the bag. A piece of paper towelling or cloth may be placed around the prawn specimens in the bag to keep them moist and to absorb any free preservative.
- Place the bag and prawn specimens into a second plastic bag, remove excess air and seal with heavy packing tape. There should be no smell of preservative from the package.
- Label each bag if more than 1 lot of prawn specimens is to be sent in the same box.
- Place labelled bags containing the prawn specimens into a strong cardboard or aquaculture-standard coolite box. Add packing to prevent prawn specimens being damaged during transport.
- Complete the specimen advice sheet (PDF, 630KB), place it in an envelope and attach it to the exterior of the box containing the prawn specimens.
- Contact the relevant Aquatic Pathologist or Veterinary Officer before sending samples to the appropriate laboratory, as listed below.
Contact the Duty Pathologist before sending samples.
Routine aquatic animal samples
Submit routine aquatic animal samples for testing to:
Biosecurity Sciences Laboratory (BSL)
Health and Food Sciences Precinct
Specimen receipt (Loading Dock 12)
39 Kessels Road
COOPERS PLAINS QLD 4108
Phone: (07) 3708 8762 (Aquatic Pathologist - submission enquiries)
Fax: (07) 3708 8861
If you need further assistance, please contact our Customer Service Centre.
- Last reviewed: 2 Mar 2020
- Last updated: 2 Mar 2020