Mass fish die-off
Report mass fish die-off to Fishwatch
Call the 24-hour Fishwatch Hotline to report large numbers of dead fish or other aquatic animals.
Freecall 1800 065 522Remaining dead fish from fish kills will often be cleaned up by:
- animals or birds
- natural tidal movement in coastal areas.
During blackwater events, dead fish decompose rapidly due to the natural bacteria present.
Information to report
Include the following important details when reporting:
- Location of dead fish, including longitude and latitude (if known).
- Your name and contact details.
- The species of organisms involved, or a description if unknown.
- The number of dead organisms.
- Size of area affected.
- When it occurred (if known).
- Current and expected weather conditions.
- Tide details.
- Any water discolouration.
Make sure you take a photo of the mass fish die off to assist with species identification.
Collect samples
Collecting samples will help us to investigate the cause of the die-off.
Contact Fishwatch for instructions on delivering the following samples.
Fish or aquatic organisms
- Collect visibly sick or dying organisms. Avoid contact with unprotected skin.
- Store in a plastic bag and place in ice slurry – frozen samples may be acceptable in some cases.
Water samples
- Use a clean glass or plastic container to collect samples.
- Rinse the container several times in the water you are going to collect.
- Fill the container approximately two-thirds full and seal it.
- Store at room temperature, except in extreme heat when it should be refrigerated but not frozen.
Harmful algal bloom (HAB)
In mid-March 2025, a significant harmful algae bloom was identified in the waters around the Fleurieu Peninsula. This HAB is ongoing with health impacts for people and wildlife.
Read the latest update