Risks to health from gathering and eating dead and dying shellfish in Whangateau Harbour

17th February 2009

Auckland Regional Public Health Service (ARPHS) is reminding the public that gathering and eating shellfish is always a risky activity.

Dr Simon Baker, ARPHS medical officer of health explained, ”we are warning people of this risk because there are a number of dead and dying shellfish in Whangataeu Harbour at present. The marine biologists and shellfish experts we’ve consulted consider this is a natural occurrence due to the recent spell of hot weather.”

“Many shellfish are filter feeders – and the shoreline cannot be easily protected against agricultural run-off, sewage overflows, failing septic tanks, algal blooms and natural die-off in hot weather. ARPHS always advises caution when gathering shellfish for human consumption.”

ARPHS was first notified of an unusual smell at Whangateau Harbour on Monday 12th January. Health Protection Officers from ARPHS visited the harbour, inspected the area, and collected cockles. These were tested for faecal contamination, and results were within normal limits. Following a further query, ARPHS Health Protection Officers revisited the harbour on 23rd January, and took further samples for biotoxins (i.e. from algal blooms). These tests were also normal.

Although all tests have been normal, ARPHS still advise the public to consume shellfish at their own risk, because there is no non-commercial monitoring of shellfish quality at recreational beaches and harbours, except for biotoxins.

Therefore to minimise your risk, ARPHS advise:

  • Avoid collecting shellfish if the shells are open, and do not close automatically. This is a sign of dead and dying shellfish, and these shellfish should not be eaten.
  • Avoid collecting shellfish from beaches for 48 hours after significant rainfall.
  • Avoid eating shellfish taken from water polluted by stormwater and sewage effluent.
  • Avoid collecting shellfish in clear plastic bags. Sacking or similar material will protect shellfish from the sun and keep them wet, cool and alive.
  • Thorough cooking, at temperatures exceeding boiling point for several minutes, will destroy most harmful bacteria and viruses. However, it is not practical for all types of shellfish as this may affect the texture and flavour.
  • Discard any shellfish that do not smell healthy after cooking

ARPHS also advises against swimming in the sea within forty-eight hours of significant rainfall, especially near to creeks and stormwater outlets.

Contact

Sally Young
021 938 431
623 4600 x 27135
sallyy@adhb.govt.nz