The Department of Primary Industries and Regional Development (DPIRD) has concluded its investigation into a fish kill reported 18.5 kms (10nm) north of Cape Preston on Sunday 2 April, involving some hundreds of reef fish.
The fish kill appears to have passed.
DPIRD liaised with various agencies and companies to survey the area to obtain further information, but no further observations were made, nor reports received.
DPIRD staff also conducted a sea patrol on Wednesday 5th searching for any evidence of the fish kill but found no dead fish.
Neap tides (on Friday 31st/Saturday 1st) and very light winds resulting in reduced water movements, combined with above average water temperatures, Trichodesmium algal blooms (since November) and possibly coral spawn may have resulted in low dissolved oxygen levels, leading to fish deaths. There was also a lot of rain before the neap tides and the nearby Fortescue and Nullagine Rivers are flowing, sending further nutrients out into the ocean which, when broken-down, would also reduce dissolved oxygen levels.
The best way the public can help is by immediately reporting fish kills to the
FishWatch 24/7 reporting service on 1800 815 507. That way, first responders have a higher chance of collecting fresh samples suitable for testing to help work out the cause of the fish kill.
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. If possible, please retain GPS coordinates and photographs ready for a call-back.
Investigation into a reported fish kill north of Cape Preston
Alert issued 4 April 2023
Investigations have begun into a fish kill reported 18.5 kms (10nm) north of Cape Preston on Sunday (2 April), involving some hundreds of reef fish including Coral Trout, Leatherjackets, Rankin Cod, Cuttlefish, Northwest Blowfish and Coral Cod.
Department of Primary Industries and Regional Development (DPIRD) officers are gathering information and assessing the extent of the fish kill. They will also collect suitable samples for laboratory testing if possible.
Neap tides and very light winds resulting in reduced water movements, combined with above average water temperatures, Trichodesmium algal blooms and possibly coral spawn may have resulted in low dissolved oxygen levels, leading to fish deaths late last week.
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 Department of Health advice:
- 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.
DPIRD 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 the department’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.