Lake Health Warnings

If there is a health warning in place:

Never swim or take part in any activity that may result in accidental consumption or exposure to water affected by algal blooms if a health warning is in place for that area, even if there are no visible signs of a bloom.

If a health warning is in place, it means that cyanobacteria (blue-green algae) are present in large numbers in that bay/lake. Cyanobacteria are capable of producing toxins that are harmful to humans and animals if swallowed or if skin is exposed to them (when swimming, skiing or kayaking etc).

The Medical Officer of Health advises against drinking water from the lakes at anytime.

If there is no health warning in place:

Wind blowing onto shore may concentrate a bloom in a bay and make it unsafe for recreational contact. This can occur at any time of the year, but is more common in warmer summer months. So even if no warnings are in place for a lake or bay, you should still assess the situation carefully before entering the water.

Caution: If the water is cloudy, discoloured or has small globules suspended in it, it is better to be cautious and totally avoid that lake or bay.

If you notice a possible bloom (such as described above) in an area where there is no health warning in place, please report the bloom location during normal working hours to Bay of Plenty Regional Council on 0800 884 880 or after hours on the Pollution Hotline 0800 884 883.

Even if the water appears completely normal to the naked eye, it can still have large numbers of algae present. If you experience health symptoms (such as those described below) that come on within minutes of contact with the water, you should avoid further contact with the water and, if symptoms persist, contact the Community Health and Disability Services 07 349 3520 (normal working hours) or 07 349 3522 (after hours) or see your doctor.

Cyano toxin health symptoms

Exposure to blooms may cause symptoms such as skin rash, nausea, tummy upset and even symptoms affecting the nervous system such as tingling and numbness around the mouth or tips of fingers. Some of these can be caused by the mere presence of large numbers of algal cells in the water, but some symptoms are related to the release of toxins by the bloom. These toxins are colourless and odourless. They are unaffected by boiling the water and can persist in the water after the bloom has subsided. They can also be released at any stage of a bloom and may or may not be localised in a bay.

Health Information

For more information on health warnings visit the Toi te Ora Public Health website, which is part of the Bay of Plenty Health Board.