The Department of Primary Industries and Regional Development (DPIRD) has concluded its monitoring of a fish kill involving an estimated 12,000 blowfish in Lancelin Bay, from Eddies Island to just north of the main jetty that was reported on 23 January 2023.
It is likely that this fish kill was caused by adverse environmental conditions.
There have been reports of large numbers of blowfish close to shore between Guilderton and Lancelin, as well as elsewhere in the south-west.
DPIRD believes the very low tides and swells resulting in reduced water movements, combined with above average temperatures and the decomposition of sea wrack may have resulted in low dissolved oxygen levels close to shore, leading to fish deaths.
As the fish kill has passed and the blowfish have been washed away, the previously-provided Department of Health advice no longer applies.
More fish kill information can be found on DPIRD’s website.
The best way the public can help is by reporting fish kills to the
FishWatch 24/7 reporting service on
1800 815 507.
When you make a fish kill report, tell us where and what you saw, including numbers of dead fish and, if possible, the species affected. And, if you have GPS coordinates and/or photographs, that will also assist DPIRD’s investigation.
Investigation underway into a fish kill at Lancelin
Alert issued 24 January 2023
Investigations have begun into a fish kill involving an estimated 12,000 blowfish in Lancelin Bay, from Eddies Island to just north of the main jetty.
Department of Primary Industries and Regional Development (DPIRD) officers have gathered information and assessed the extent of the fish kill and have observed large quantities of sea wrack (seaweed and seagrass) along the shore and the water is discoloured because of the wrack for approximately three kilometres. There is also a strong smell of rotting sea wrack.

Rotting sea wrack stretches 3kms along Lancelin Bay
Very low tides and swells resulting in reduced water movements, combined with above average temperatures may have resulted in low dissolved oxygen levels, leading to fish deaths.
Pet owners should take particular care to prevent pets from eating the washed-up blowfish. Blowfish toxicity can be life-threatening to pets. Therefore, immediate veterinary attention should be sought if you notice your pet having contact with or eating a blowfish.
Updates will be issued if further information becomes available. In the meantime, people are reminded to stay safe around fish kills. We urge people to follow the general Department of Health advice below.
- not to swim in areas of water with large numbers of dead and decomposing fish because they may contain high levels of bacteria and have an objectionable odour;
- not to fish in water with large numbers of dead fish;
- temporarily not to collect or consume fish from the waters near a fish kill;
- not to collect and use dead fish for bait or consumption because of the risk of high levels of bacteria; and
- not to allow pets and other animals to come into contact with dead or decomposing fish either in the water or on shore.
Our officers have been trained to collect fish and water samples using appropriate safety methods and equipment. The best way the public can help is by reporting fish kills to the
FishWatch 24/7 reporting service on
1800 815 507. Tell us where and what you saw, including numbers of dead fish and, if possible, the species affected. And, if you have GPS coordinates and/or photographs, that will also assist DPIRD’s investigation.
FURTHER INFORMATION:
DPIRD is responsible for responding to fish kill events that occur in ocean environments. DWER manages investigations on fish kills that occur in estuaries, rivers and naturally occurring inland water bodies. The Department of Biodiversity, Conservation and Attractions manages investigations of fish kills that occur in the Swan Canning Riverpark.
In all circumstances, DPIRD’s laboratories carry out testing of any suitable fish samples and this can take some time.
Fish kills in open ocean areas may provide less evidence of a direct cause and we explore all possible explanations. It may not be possible to identify a single definitive cause, but every effort is made to establish probable factors. More
fish kills information can be found on DPIRD’s website.