Cyanobacteria sighted in Tomahawk lagoon

Potentially toxic blue-green algae (cyanobacteria) has been collected from the Tomahawk lagoon in Dunedin, prompting a warning from the Otago Regional Council for people to avoid contact with the waters of the lagoon in the meantime and keep dogs away too.

Testing of a sample ORC took from the lagoon yesterday indicates the presence of high levels of cyanobacteria. Signs have been put up to warn the public of the risks associated with the bloom.

Cyanobacteria can produce toxins that are harmful to humans and animals if swallowed or through contact with skin. Exposure to cyanobacteria may cause symptoms such as skin rashes, nausea, tummy upset, and tingling and numbness around the mouth or tips of fingers. 

Anyone experiencing health symptoms after contact with contaminated water should visit their doctor. Public Health South can be contacted via the Dunedin Hospital switchboard - (03) 474-0999 - to provide health professionals with information about those symptoms.

Dogs coming into contact with the cyanobacteria should be hosed down in the first instance to remove it from their skin, and a veterinarian contacted should their condition worsen.

Cyanobacteria occur naturally but can increase rapidly during summer months, particular when the weather has been warm. If the water is green or has floating bright green or blue scums, all contact should be avoided. Not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the bloom has disappeared. 

ORC will continue to monitor and update the public as the bloom changes.

For more information please contact:

Dr Dean Olsen
Manager Resource Science
Ph 0800 474082 or 027 6022737

Communications contacts

Southern District Health Board:
Moira Finn
Senior Communications Advisor
Ph 03 476 9830 or 027 836 4718
Email: moira.finn@southerndhb.govt.nz

Dunedin City Council
Jamie Shaw
Senior Communications Adviser
Ph 03 4774000
Email: Jamie.shaw@dcc.govt.nz

Mark Peart 
Team Leader Communications – Channels
Ph 0800 474082 or 027 5312620
Email: mark.peart@orc.govt.nz