Swimming with sharks could be safer than eating some varieties of fish sold in New Zealand, says Green Party Food Safety Spokesperson Sue Kedgley today.

Battered fish tested in Dunedin have a mercury level ten times that of battered fish in Napier. Battered fish in Auckland is also much higher in mercury than in other regions - The latest New Zealand Food Safety Authority diet survey shows
'New Zealanders deserve answers as to why battered fish samples tested in Auckland and Dunedin are significantly higher in mercury than in other areas,” says Sue.
New Zealanders should also know why fresh fish from Dunedin is found to have twice the level of arsenic than fish on sale in Auckland, says Sue.
Longer lived predatory fish such as shark or flake, swordfish, marlin and broadbill tend to build up their mercury levels.
Shark is a common ingredient in fish and chips. Research published last year in the Medical Journal of Australia suggests even relatively low levels of mercury can affect children's brain development, says Sue.
A recent MAF Biosecurity decision allows the importation of Vietnamese catfish farmed in the Mekong River to be imported in significant quantities to New Zealand, despite concerns being raised about water pollution in the Mekong River.
'Because we don't have mandatory Country of Origin Labelling, no-one will know if some of these Vietnamese catfish are turning up in the latest diet survey and explaining the high levels of mercury in some fish,” says Sue.
Battered fish in Dunedin and Auckland also have higher levels of methyl mercury.
'Methyl mercury can cause irreversible damage to the central nervous system, and can cross the blood-brain barrier and the placenta and accumulate in the body,” says Sue.
Fresh fish from Dunedin contained more than twice the level of arsenic found in fish on sale in Auckland.
'The levels were so high in Dunedin that even one fish meal a week is likely to push the intake beyond the World Health Organisation's ‘Tolerable Weekly Intake' - especially for women,” says Sue.
High levels of cadmium and arsenic found in oysters and some varieties of fish also concern Sue.
Arsenic and Cadmium are cumulative and toxic elements, and high levels of cadmium and arsenic can have serious effects on health.
'This is especially concerning given that ERMA has warned that ten per cent of water in New Zealand has high levels of arsenic.”