Twenty volunteer citizen scientists took to Lake Wairarapa last weekend alongside Greater Wellington Regional Council staff to collect, record and replace native freshwater mussels.

GWRC biodiversity officer Toni de Lautour said it was a perfect day in the lake and the teams collected quickly, working across designated zones recording data.

"There were good numbers in this area although volume does not necessarily indicate a healthy population," she said.

"The size and condition of the samples need to be analysed and this will provide us with a clearer picture."


This was the second monitoring event of this long-term programme to understand the health of the kakahi population at Lake Wairarapa, an essential part of a long-term plan towards restoring the wetlands.

"The status and health of the kakahi (mussel) population helps us to understand the health of the wider ecosystem and can measure the progress of restoration activities," said GWRC spokeswoman Brigitte de Barletta.

"The monitoring takes place on an annual basis and the information will be collated into a new national database as well as support the decision making of Wairarapa Moana partners."

There are three species of kakahi in New Zealand and two of these are found in Lake Wairarapa.

They can live between 30 and 50 years and grow to 60 to 80mm, although there are records of much larger specimens.

There are records of kakahi found in the Kopuaranga and Whangaehu and the lower reaches of the Ruamahanga River, although in much lower numbers than they once were.

They appear to be more plentiful in Lake Wairarapa. Kakahi don't usually live in heavy gravel rivers, such as the Waiohine and Waingawa, as these rivers lack the stable and sheltered spots kakahi favour.

Enhancing the ecology and the recreational and cultural opportunities around Lakes Wairarapa and Onoke is managed through a long-term collaboration, the Wairarapa Moana Wetlands project, a joint commitment by: South Wairarapa District Council, Ngati Kahungunu ki Wairarapa, Rangitane o Wairarapa and Papawai and Kohunui marae, Department of Conservation and Greater Wellington Regional Council.