A total of 800 tonnes of sea lettuce has been collected from Tauranga shores in the past week.

The Bay of Plenty Regional Council said it was the first collection for summer.

Regional council technical advisor Bruce Gardner said sea lettuce was natural but could be a nuisance when it washed ashorer.

Mr Garden said Tauranga Harbour's sea temperatures of 15 to 20C meant it was the perfect place for it to grow.


Mr Gardner said that Regional Council's scientists have been checking on sea lettuce growth in the lead up to summer.

"It's normal for sea lettuce accumulations to wash ashore in Tauranga Harbour, especially when contributing wind and tidal conditions align. Despite the build-up at Matua, growth levels throughout the harbour so far are below the long term average for this time of the year and a neutral El Nino/La Nina weather pattern is forecast for this summer. So at this stage we've got no reason to expect any exceptionally large blooms this summer," Mr Gardner said.

Mr Gardner said it and the Tauranga City Council would continue to collect nuisance accumulations from popular beaches as needed over summer. He said that the councils have a three-pronged approach to managing sea lettuce.

"We're reducing nutrient inputs to the harbour by working with land, business and infrastructure owners to clean-up land run-off, we're funding research projects through the University of Waikato Coastal Science Chair, and we collect nuisance accumulations from busy beaches. No untreated waste discharges have been allowed into the harbour since the 1990s," he said.

Sea lettuce concerns can be reported to Bay of Plenty Regional Council's Pollution Hotline on 0800 884 883 or Tauranga City Council on 07 577 7000. Further information about sea lettuce in Tauranga Harbour is available at www.boprc.govt.nz/sealettuce.