Health Warning – Algal Bloom in Okawa Bay

5 January 2024

Health warnings issued for Okawa Bay at Lake Rotoiti

A health warning has been issued for Okawa Bay at Lake Rotoiti, in Rotorua, due to a bloom of “potentially toxic” blue-green algae, Toi Te Ora Public Health says.

People should avoid any activity that results in contact with the water, Toi Te Ora said in a Facebook post on Friday.

Algal blooms can develop rapidly and unpredictably and sometimes produce toxins that are harmful to people and animals, medical officer of health Dr Gregory Evans said in a media release in December.

“These blooms have the capacity to release toxins into the water which can cause skin rashes, stomach upsets and visual problems for anyone who has contact with the water,” Evans said.

“They can also affect the nervous system causing numbness, difficulty with breathing, and asthma attacks.”

New signs warning lake users of toxic algal blooms have been put up around 40 lakeside locations in the Rotorua district.

Lakes were typically dominated by free-floating algal blooms, while rivers were more prone to algal blooms that grew in mats attached to rocks at the bottom. They could also build up at the shoreline.“Algal mats and scum can build up along the edges of lakes or rivers. It’s important parents ensure children avoid contact with these as they may be toxic.”

Dogs were also at risk of “serious illness” if they consumed or had contact with toxic algae or algal mats that might accumulate in and around rivers. They should be kept away from the water if it looks like there may be a bloom.

Lake Rotoiti also had a blue-green algae bloom last summer, including in Okawa Bay.

Lakes are monitored by the Bay of Plenty Regional Council from October to March and health warnings were issued by Toi Te Ora if test results show there is a bloom.

Algal blooms: Look before you leap

It is always best to avoid contact with the lake water if it:

looks discoloured

has an unusual smell

has green or brown particles suspended in it or has visible surface scum.

If you think you’ve been in contact with an algal bloom:

have a shower and change your clothes as soon as you can, even if you don’t have any symptoms

seek medical advice from your GP if you become unwell after having contact with recreational water.

Up-to-date information on health warnings for the Bay of Plenty and Lakes districts is available through these channels:

* Phone: 0800 221 555

* Website: www.toiteora.govt.nz/health-warnings

. * More information: www.toiteora.govt.nz/public/recreational-water

. * Facebook: www.facebook.com/toiteora

. * Twitter: www.twitter.com/toiteora

. * Instagram: www.instagram.com/toiteora

. * Subscribe to health warning email alerts: www.toiteora.govt.nz/news