A group of volunteers and the Greater Wellington Regional Council are working together to find out how many kakahi or freshwater mussels are in Lake Wairarapa.
According to the National Institute of Water and Atmospheric Research kakahi are under threat and are in decline.
The native shellfish were a valuable food resource to Maori and can be found through out New Zealand mainly in small, fast-flowing streams and lakes.
The Wairarapa Moana Wetlands team is also part of the project which is the first of its kind where volunteers will be involved in counting how many of the freshwater mussels live in Lake Wairarapa.
The regional council said a survey was done two years ago and revealed that the average shellfish size was large, meaning they were mostly older.
The council wants to get an update on what is happening to the population and their age distribution.
There are three species of kakahi in New Zealand and two of these are found in Wairarapa.