Public to seek Wairarapa mussel secrets

TRAINING: Jamie Steer (left), Amber McKeown and Paul Curry hone their kakahi counting skills at a volunteer training day. PHOTO/SUPPLIED BY GWRC

The secrets of Wairarapa's kakahi, or freshwater mussels, are hoped to be revealed as part of a new community science monitoring programme.

Greater Wellington Regional Council and the Wairarapa Moana Wetlands team, along with volunteers, will be carrying out the project to find out more about the kakahi population in Lake Wairarapa.

It will be the first time community volunteers have been involved in kakahi counting in New Zealand.

GWRC biodiversity adviser Toni de Lautour said a survey carried out in 2012 had shown significant gaps in what was known about the kakahi population of Wairarapa Moana but the average shellfish size was large, meaning they were mostly older.

"The idea is to collect data, analyse that and give us information about what's happening to the population and their age distribution."

She said the other aim of the programme was to engage people by informing them about kakahi ecology and their wetland habitats.

Six volunteers were trained last weekend in anticipation of the first kakahi count day on March 21. "We'll still need another 10 or so volunteers to help on the day."

On the count day, volunteers will measure and record information about the kakahi and return them safely to the lake.

Mrs de Lautour said the monitoring will be carried out every year, alternating between two sites at Lake Wairarapa - Lake Reserve at the top end of the lake and Western Lake Reserve.

She said it will be ongoing project, contributing to local knowledge and to a national database, which is being set up by Niwa.

According to Niwa, there has been limited research undertaken in New Zealand investigating the key drivers influencing presence, distribution, and density of freshwater mussels in lakes.

However, it is known they are under threat.

"The freshwater mussel population is in decline which could be related to the degradation of wetland habitats and the widespread decline of native fish," said Mrs de Lautour.

Native fish play an important role in the kakahi life cycle, as hosts of the kakahi's larval stage.

The larva attach to the fish a little like parasites in the early part of their life before moving to soft, sandy sediments in lake and river beds.

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

-If you are interested in becoming a volunteer, contact Mrs de Lautour on 06 826 1535.