Media Release

Councils to work together on sea lettuce

For immediate release: 15 September2009

Environment Bay of Plenty, Tauranga City Council and Western Bay of Plenty District Council will be working together to help in the clean up of an anticipated abundance of sea lettuce in and around Tauranga Harbour this summer.

The Climate Prediction Center is predicting El Niño weather patterns this spring/summer, which means more sea lettuce.

Environment Bay of Plenty and Tauranga City Council will contribute $30,000 each to help with cleaning up the sea lettuce from the city’s harbour and beaches. This could include ‘pick up’ from sea as well as from the seabed at low tide.

"The increased funding means we can pick up sea lettuce as often as it becomes a problem. Last year we were only able to do one pick up after Christmas. This year, with both Tauranga City Council and Environment Bay of Plenty combining resources, we will be able to do several pick ups before Christmas so there will be far less sea lettuce rotting on the beach over the holiday season," Tauranga City Council Park Ranger Craig Fea said.

Environment Bay of Plenty Chairman John Cronin said that while sea lettuce is a naturally-occurring algae and not caused by pollution, he could appreciate the public’s concerns about how annoying it was and the offensive smell rotting sea lettuce gave off.

“Tauranga Harbour is a key area of focus in our Ten Year Plan and we felt that given the expected increase in sea lettuce this summer it was important to work with the community and support the local councils in the region to help clean up this nuisance algae,” Chairman Cronin said.

Environment Bay of Plenty Senior Environmental Scientist Stephen Park said latest sea lettuce monitoring from three sites across Tauranga Harbour (Harbour Drive, Grace Road and Ongare Bay) showed an increase in the average amount of sea lettuce compared to previous years – an increase that correlates with El Niño.

“The El Niño weather pattern brings persistent westerly winds that drive coastal water offshore. In these conditions nutrient-rich water from the deep ocean moves into shallower water (called up-welling) which then enters the harbour,” Mr Park said.

“The natural increase in nutrients provided through up-welling during El Niño are the main cause of the sea lettuce blooms in Tauranga Harbour,” he said.

Environment Bay of Plenty has been monitoring sea lettuce growth since 1991 and has done extensive research into how it grows.

“We check the Tauranga Harbour every two months, getting data on sea lettuce abundance, the level of nutrients in the harbour and other environmental factors that could be influencing blooms in Tauranga Harbour,” Mr Park said.

Environment Bay of Plenty is also conducting trials to evaluate the potential of sea lettuce for vermicomposting.

Pictured: Environment Bay of Plenty Senior Environmental Scientist Stephen Park.

Facts about Sea Lettuce

• Sea lettuce is a naturally occurring algae
• It is native to New Zealand
• Its occurrence is a natural event and not caused by pollution
• Early Maori used the edible sea lettuce in cooking. Sea lettuce is still eaten today in salads and stews around the world
• Sea lettuce blooms are linked to climatic conditions
• Sea lettuce can be used as a compost and fertiliser but needs to be mixed with other materials before it is used

ENDS

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