Media release: Māori and western science combine in latest wildlife translocation

Wellington – 21 April 2022: Māori knowledge and western science have come together again to support the latest wildlife translocation to Zealandia Te Māra a Tāne.

On April 20, 150 kākahi/freshwater mussels (Echyridella menziesii) were re-homed into Roto Māhanga within the Wellington ecosanctuary, with the goal to continue the journey towards restoring the lifeforce, or mouri, of the Kaiwharawhara catchment. The boost in numbers will increase genetic diversity and breeding success of the rare freshwater species.

The translocation connected a deep archive of Māori knowledge and conservation techniques to better protect and conserve kākahi.

Special kete, or baskets, were woven by Roopu Rāranga o Manaia for use in the translocation. This group is supported by the Tenths Trust.

“The importance of using these kete is that they are keeping cultural practices alive. These kete have allowed us to share information and techniques and to stimulate questions and conversations around the protection of cultural materials and knowledge,” says Terese McLeod, Taranaki Whānui and Bicultural Engagement Lead Ranger at Zealandia.

“Modern things are useful and have value but so do the more traditional things. They allow us to visualize another time and another way of life and how we do things.”

The kete design is called waikawa and is made from raw harakeke with a flat base to prevent the kākahi from getting caught and straps to allow the kete to be worn in the water.

The kākahi were collected from Lake Kohangapiripiri by representatives from Taranaki Whānui te Upoko o te Ika, Zealandia Te Māra a Tane and Greater Wellington, and transported in the kete.

The kākahi were stored in quarantine to prevent any unwanted organisms being introduced into Zealandia, before being released into the upper reservoir on 20 April.

This is the second translocation of its kind, with 200 kākahi being translocated into Zealandia in 2018. Monitoring of the original population has informed that Roto Māhanga, the upper reservoir in Zealandia, is a fantastic spot for kākahi to thrive.

Kākahi are filter-feeders, and feed on a variety of particles in the water, including phytoplankton, bacteria, and organic matter. Through this filtering, kākahi improve water quality and are key to keeping lakes balanced and healthy.

“The successful re-homing of these Kākahi is testament to the strong partnership between Greater Wellington and Taranaki Whānui, set out in Rōpū Tiaki, a long-standing guardianship group between our organisations over Parangarahu Lakes,” says Jimmy Young, Rōpū Tiaki Co-Chair and Greater Wellington Parks Manager.

“Rōpū Tiaki is also working with Zealandia to develop a mātauranga Māori and western science approach to monitor kākahi at the lakes. Rōpū Tiaki, are thrilled to gift the kākahi to support a revitalised Roto Māhanga, and through their filtering abilities, support marine ecosystems downstream.”

This project is part of Zealandia’s Sanctuary to Sea Kia Mouriora te Kaiwharawhara project, which aims to restore the mouri of the Kaiwharawhara catchment. This catchment begins within Zealandia Te Māra a Tāne.

Zealandia Chief Executive Dr Danielle Shanahan says, “Zealandia is striving to become the best Te Tiriti o Waitangi partner it can be. The kākahi have brought us together on this journey as we continue to breathe life back into the Kaiwharawhara.”

ENDS

About kākahi

Kākahi are endemic freshwater mussels. There are three species in Aotearoa, two of which are found at Zealandia.

The kākahi involved in this tranlocation is Echyridella menziesii (At Risk- Declining): found throughout NZ (esp Lake Taupō and Rotorua).

They have a rounded shape, and generally found along stream banks and under cover.

Kākahi are filter-feeders, and feed on a variety of particles in the water, including phytoplankton, bacteria, and organic matter. They lack the ‘beard’ that some marine mussels use to attach themselves to rocks, instead partially burying themselves into sediments. As they move around, they can leave trails in the sediments at the bottom of lakes and rivers

In spring, males release their sperm into the water, where it is taken in by females to fertilise their eggs, inside a brood pouch in the gill. The eggs develop into larvae about the size of a grain of sand. The larvae attach themselves to a host fish species like kōaro or toitoi/common bully using a small tooth on their shell edge. They stay attached to the fish for about 2-3 weeks while they transform into a juvenile mussel, at which point they drop off into soft sediments at the bottom of the lake or river. This life cycle prevents kākahi from being washed out to sea and allows them to disperse away from their parents. Juvenile kākahi live in sediments for 5 years before they emerge

Kākahi improve water quality as they are filter feeders – they are incredibly efficient filterers, able to filter one litre of water per hour!

As they were generally available all-year round, kākahi were viewed as a reliable food source for Māori. They were also used as rongoā, as well as feeding motherless infants. Their shells were also used to cut hair, umbilical cords, scrape vegetables and as raddles on kites.

Kākahi are under threat and declining in Aotearoa, likely due to factors like habitat modification or destruction, water pollution, and possibly through the loss of host fish species which are critical for kākahi to complete their life cycles.

For more information contact: 

Zealandia Te Māra a Tāne: Gini Letham, Lead Ranger Science Communication- 020 4010 2430, media@visitzealandia.com

Greater Wellington: Jesse Gerritsen, Media Advisor, 021 584 494.