Source: Auckland Council
Auckland Council is warning residents and visitors to Waiheke Island to avoid black algae present on two beaches on the island.
The cyanobacteria Okeania spp (previously classified as Lyngbya majuscule) has been detected on beaches at Surfdale and Blackpool on the southern coast of the island. This is the same algae that was present on the island’s coast last summer.
This month, laboratory testing of samples of the algae has confirmed the presence of Okeania spp. We are awaiting lab test results to confirm whether the toxin Lyngbyatoxin-A is present.
The Auckland Regional Public Health Service advises that the algal bloom could lead to skin, eye and respiratory irritations.
The public are advised not wade in the water or touch the algal material at the affected beaches.
Barry Potter, Auckland Council’s Director of Infrastructure and Environmental Services said the council is monitoring the situation.
“We will continue to monitor the scale and impacts of this naturally occurring phenomena in case any further advice or intervention is required.
“We understand the public may have concerns around this news and we thank them for their patience and cooperation.”
Deputy director-general of New Zealand Food Safety (NZFS), Vincent Arbuckle, says NZFS is advising the public not to consume shellfish from Surfdale and Blackpool beaches.
“Affected shellfish include bivalve shellfish such as mussels, oysters, tuatua, pipi, toheroa, cockles and scallops, as well as pūpū (cat’s eyes), Cook’s turban and kina (sea urchin). It is important to remember that cooking does not make the shellfish safe to eat. Finfish are not affected by this public health warning, but people should gut the fish and discard the liver before cooking.”
Staying safe at affected beaches
The beaches where the algae is present remain open to the public but Auckland Council advises the following:
-
Avoid contact with the algae, including wading in affected areas, as it could lead to skin, eye and respiratory irritation
-
If you feel unwell as a result of contact with the bloom, you should contact your doctor, or call Healthline on 0800 611 116
-
Do not gather or take algae from the beach for things like using on your garden
-
Keep dogs away from the algae and any decomposing material which could cause a reaction
-
Do not gather or consume shellfish from the affected beaches.
Frequently asked questions about Cyanobacteria
What are Cyanobacteria?
- Cyanobacteria (or blue-green algae) are naturally occurring microscopic organisms that live in a range of aquatic environments, from near-pristine to those more impacted by land use.
Are Cyanobacteria harmful to humans?
- Lyngbya species of Cyanobacteria (including Okeania spp. and Moorea spp) are known to produce toxins – collectively referred to as lyngbyatoxins – which could lead to skin, eye and respiratory irritations.
Do Cyanobacteria originate from outside New Zealand?
- No. Cyanobacteria are naturally occurring in New Zealand waters.
Are Cyanobacteria common in New Zealand waters?
- In New Zealand, blooms of the filamentous cyanobacterium identified at the time as L. majuscula have been reported in various parts of the Hauraki Gulf particularly in the Omana Beach area. There have also been reports of previous summer blooms at sites in eastern Auckland in the Hauraki Gulf (Musick Point, Eastern Beach and Howick) as well as sites in the Manukau Harbour (Kaitarakihi Bay) and at North Head in the Waitematā Harbour. Some of the earliest records of Lyngbya spp. go back to surveys in the 1950s and in the 1970’s it was described as a seasonally dominant species on rock platforms around Motukaraka Island. Through the 2000’s there were regular occurrences of blooms around the Beachlands and Ōmana areas.
What impact does Cyanobacteria have on the environment?
- Some cyanobacteria blooms can have serious impacts on aquatic ecosystems in general including potential toxic effects due to smothering and shading. However, there is a lack of research when it comes to the environmental impacts of Lyngbya spp.
