ANGLERS who pursue Spanish mackerel might just think twice about keeping larger fish after what is believed to be the southernmost recorded outbreak of ciguatera fish poisoning.
At Evans Head last week, staff members of a local restaurant fell ill after eating a locally caught Spanish mackerel, and ciguatera looks to be the culprit.
It follows a confirmed outbreak on the Gold Coast last week from a 12kg fish caught off Palm Beach which led to a number of people being hospitalised.
The poisoning is caused by an accumulation up the food chain of a toxin produced by a dinoflagellate that grows on algae associated with dead coral.
Small fish eat the algae, are eaten by larger fish and so on until a human gets it.
The toxins are tasteless, odourless, survive cooking or freezing and can’t be detected without lab tests.
Outbreaks are sporadic and unpredictable, affecting up to 50,000 people a year worldwide and mainly occur after people eat any of about 400 species of large predatory tropical fish, including bigger Spanish mackerel, coral trout, red emperor and other popular reef table fish.
The Evans Head workers had the classic skin tingling and ‘cold-feels-hot, hot-feels-cold’ symptoms and one had serious gastrointestinal illness and was admitted to hospital for two nights.
No customers were involved, the owner said.
The 16kg fish was caught at Riordans Reef on February 12 by a licensed fisher who processed it in accordance with best practice.
It was bought from the Fishermen’s Co-op the following day and kept hygienic and chilled throughout.
“Each staff member ate about 100g of meat,” the owner said yesterday.
“There’s absolutely no negligence.
“The ironic thing is that as I filleted the fish, I joked to staff that it had a particularly evil look on its face!”
NSW Food Safety was notified and lab test results on the fish samples should be available in about a week.
Ciguatoxins accumulate in human body fat and possibly in muscle tissue.
People develop no immunity and subsequent attacks tend to be more serious.
Recurrence can be brought on by stress, exercise, rapid weight loss, alcohol and eating fish that are not necessarily ciguateric, including cold water species.
Excretion of the toxin is slow and incomplete, in part by the urinary system.
The last known ciguatera poisoning in NSW was at Brunswick Heads about a decade ago, although there was some conjecture that the mackerel in question had come from a ciguatera hotspot in Hervey Bay.
The dinoflagellate is prevalent in areas that have had some ecosystem disruption, such as industrial or agricultural pollution, human effluent, reef damage from cyclones or coral bleaching.
Fisheries and food safety advisers recommend that people choose mackerel under 10kg whole weight.