Snapper with cloudy eyes and other symptoms
In May 2024, The Ministry for Primary Industries (MPI) received reports of some snapper caught in Kaipara Harbour (Auckland region) that presented with cloudy bloodshot eyes that had cataracts, and other symptoms such as loss of condition and fin damage.
Some media reports have referred to snapper with this condition as "zombie" snapper.
This condition has been seen in the past and in different locations around the country.
Most recent reports of snapper caught with the condition have come from around the Kaipara Harbour area, although we've also had some reports from other areas (Kāpiti and Whangārei).
Biosecurity New Zealand conducted an investigation to determine if exotic or emerging diseases and parasites were responsible for the condition.
Cloudy eyed snapper from Kaipara Harbour and other areas – Biosecurity New Zealand report [PDF, 906 KB]
Lab reports
Following this report, Fisheries New Zealand conducted a comprehensive range of tests on 12 samples of affected fish. Of these samples, 7 were caught from the Kaipara Harbour, 1 from near Raglan, 1 near Paekākāriki, and 3 from Whangārei Harbour. We have not had any confirmed reports of this condition in other fish species.
Laboratory test reports of snapper with cloudy eyes [PDF, 13 MB]
As a precaution, we continue to test affected fish and ask that people provide samples of snapper or other fish species that display the symptoms.
Can you eat cloudy eyed snapper?
While testing to date has not found any food safety concerns, our advice is that if any animal you catch or hunt looks unhealthy, including snapper showing the cloudy eye symptoms, you should not eat it.
The testing we've done to find a cause for cloudy eyed snapper
Histological examinations and tests for heavy metals, including aluminium, and PCBs (chemicals) have not identified a cause of the condition, nor has subsequent testing for naturally occurring biotoxins.
Between June and September 2024, tests were undertaken on 12 samples of affected snapper (collected in May and June) looking for possible causes including from exotic or emerging diseases, parasites, pollutants, and environmental factors.
- Initial tests ruled out any exotic or emerging diseases and parasites in the affected samples.
- Fisheries New Zealand contracted the Cawthron Institute to test affected snapper for common foodborne pathogens and contaminants, including heavy metals. These tests did not find any cause for concern. New Zealand Food Safety concluded that the food safety risk of the levels of aluminium in affected snapper is estimated as low.
- Subsequent testing for naturally occurring biotoxins did not conclude these as the cause. However, it’s possible that biotoxins may have left their system before the fish were captured.
- Our analysis has shown that snapper with cloudy eyes have very different symptoms to snapper with milky white flesh syndrome.
Find out about milky white flesh syndrome
Anecdotally, there has been a decline in reports of fish being caught with the condition, which could suggest seasonal factors at play.
Further research and testing
Our most recent tests looked for the presence of naturally occurring biotoxins.
Naturally occurring biotoxins are produced by organisms known to proliferate in shallow sheltered areas, like harbours, when ocean temperatures are elevated, as we’ve seen with recent marine heat waves. These are also areas where snapper will forage for food, such as shellfish that may be contaminated by naturally occurring toxic algal blooms.
While our tests, based on samples collected in May and June, have not confirmed biotoxins as the cause, we will continue to monitor this over the summer months when biotoxins are more common. It is possible the agent causing the cloudy eye condition had exited the bodies of the fish by the time we received the samples.
How you can help us continue monitoring snapper with cloudy eyes
As a precaution, we'll continue to test affected fish over the 2024–25 summer.
We ask that fishers continue providing samples of snapper or other fish species that display the symptoms.
Anyone wanting to provide samples should:
- contact us as soon as possible on freephone 0800 809 966
- keep the fish whole (not gutted or filleted)
- store the fish in the fridge (not the freezer).
