糖心Vlog

The use of bathyscopes is currently used by iwi, in particular Te Arawa, to monitor k膩kahi populations in their lakes. We found this method resulted in consistently fewer k膩kahi being observed than snorkelling, though greater safety, simplicity and lack of expense of using a bathyscope provided advantages for that method for iwi usage.

Associate Professor Ian Duggan (Ng膩i Tahu) and his collaborators have published an important new  investigating k膩kahi (Echyridella spp.), a freshwater mussel with high cultural significance to M膩ori, particularly to Te Arawa and Ng膩ti T奴wharetoa.

Population densities of k膩kahi are thought to have declined in many locations, and accurate methods to monitor changes in populations are needed. Bathyscopes are currently used by iwi to monitor k膩kahi populations in lakes Rotorua and Rotoiti. However, it is unclear how accurate this method is for determining abundance changes in k膩kahi relative to underwater methods, such as snorkelling.

Undergraduate student Siobhan Nuri (Te Arawa) examined mussel densities at ten sites in Lake Rotorua and Lake Rotoiti as part of an Undergraduate Research Project. She found significantly fewer k膩kahi were observed using a bathyscope relative to snorkelling, although a clear relationship existed between the numbers found with each method.

Although the results showed that snorkelling generally provided greater estimated numbers, the bathyscope method is inexpensive, safe and simple, and provides good estimates of patterns of change in abundance. Overall, the bathyscope method is ideal for use by iwi and community groups for long-term monitoring of k膩kahi populations.

Siobhan was supervised by Ian Kusabs (Te Arawa, Ng膩ti T奴wharetoa) and Ian Duggan (Ng膩i Tahu). She is now undertaking an MSc(Research).

Read the full research publication on Taylor & Francis Online.