Lake Taupo has been hit by a potentially toxic algal bloom.
The bloom of blue-green algae is from the same family as that plaguing Rotorua's lakes, but its species has not been established.
The bloom could be a symptom of declining lake water quality, a scientist said.
It was discovered this during Environment
Waikato's routine monitoring.
Water scientist Bill Vant said samples were collected at three deep-water sites. The next step was to establish the bloom's concentration levels.
The cells of the blue-green algae have been recorded in Taupo's water for at least 50 years but the reported bloom is only the second to hit the lake. The first was reported two years ago.
The bloom had the potential to cause harm because almost all species could be associated with toxins, Mr Vant said.
A blue-green algae bloom in the Waikato River this year prompted health warnings for people to avoid contact with the water.
"At this stage we don't know whether we're concerned because we've only got interim results but what I'm still waiting for is something to tell us how much is in these samples," Mr Vant said.
The toxins can cause an allergic reaction when they come into contact with skin.
Mr Vant said the bloom could be a reflection of the changes in the lake's catchment.
- NZPA
Herald Feature: Environment
