Water quality is worsening in Lakes Okataina, Tarawera and Tikitapu (Blue Lake), an Environment Bay of Plenty report shows.
The report, released at a regional council meeting, revealed that the lakes, regarded as three of the healthiest in the Rotorua area, are showing signs of degradation.
The report, by regional council environmentalscientist Paul Scholes, also said Rotorua's healthiest lake, Lake Rotoma, was showing early warning signs of some deterioration in water quality.
Lakes Strategy co-ordinator Paul Dell said monitoring of the lakes would continue over the next year to see if the water quality trends continued.
"It is early days. We are conscious of it at this stage. We are not panicking. We have raised issues that we will now keep a close eye on and see where it is when we next review it. They are still high-quality lakes."
LakesWater Quality Society chairman Ian McLean said the report showed none of the lakes in the region was safe.
"All are being damaged by human activities - household, farms, forestry or introduction of new lake weeds.
"The results show that the urgency being given to the lakes by Environment Bay of Plenty is more than justified."
The report came as the last health warning was lifted on the Rotorua lakes. It had covered Okawa Bay on Lake Rotoiti, described as the sickest of the region's lakes.
Meanwhile, a survey by Environment Bay of Plenty has found a "pretty high" level of awareness among boaties of the threat of transfer of pest weeds from one lake to the next.
Bay of Plenty Polytechnic students surveyed boat users at lake ramps on checking their boats and trailers for exotic weeds and fish eggs.
The survey, in the second week of January, found about 46 per cent of boaties knew of their responsibilities and had a good understanding of issues surrounding pest weed.
Eighteen per cent had a reasonable understanding of the problem.
The remainder, just over a third, had a low level of understanding and could potentially pose a threat.
The survey results will inform a pest management plan for the lakes, in consultation with authorities such as the Rotorua District Council and Te Arawa Maori Trust Board.
- NZPA
Test for boaties
Boaties surveyed on checking their boats and trailers for exotic weeds and fish eggs showed:About 46 per cent had a good understanding of issues surrounding pest weed.
About 33 per cent had a low level of understanding and could pose a threat.
