Monitoring Kākahi in Cashmere Stream

Three species of native freshwater mussel, or kākahi, occur in Aotearoa. The only species of kākahi found in the South Island has an ‘At Risk’ conservation status, due to its declining population, attributed to various threats including degraded habitat quality and reduced water quality.

This decline is worrying, not only because kākahi hold significant cultural value as taonga species, but also because their filter-feeding activity plays a crucial role in purifying our freshwaters.  

The Instream Team heads down, tails up.

Cashmere Stream is home to one of the larger kākahi populations in Christchurch. Situated within a rapidly developing catchment, the kākahi here are vulnerable to sediment runoff. We therefore worked with the city council to design a robust programme to monitor kākahi numbers and population structure over time.

After two rounds of intensive monitoring, we’ve found that the Cashmere Stream kākahi population is stable, despite the pressure it faces. This monitoring programme will enable the council to keep an eye on the kākahi over time, so they can help look after our waterway too.

Good numbers of kākahi collected during the Cashmere Stream kākahi survey. 

You can read more about our efforts on this project by viewing the monitoring report we prepared for the Christchurch City Council: Kākahi Monitoring in Christchurch 2023.