Native Fish Surveys.
Canterbury is home to over 60% of Aotearoa’s braided river systems — dynamic habitats that support threatened species from the mountains to the sea, ki uta ki tai. Among them, the Waimakariri River is a lifeline for native fish, birds and aquatic life.
To better understand the fish communities near the Waimakariri River intake, Central Plains Water Limited (CPWL) engaged NIWA to carry out preliminary native fish surveys using fyke netting and electrofishing techniques. These methods are designed to detect fish species, abundance and size in areas where fish may interact with CPWL’s intake infrastructure.
The surveys provide insight into how fish — especially native species — use the river and intake channel, and whether they are effectively excluded by the fish barrier in place. Day and night sampling using fine-mesh nets, along with electrofishing at five key locations, helps build a clearer picture of fish movement and habitat use.
While the surveys are not formal effectiveness trials, they offer early-stage data to guide future fish passage planning and compliance under CPWL’s consent requirements.
“This work helps us understand which species are present and where, so we can refine our approach and ensure the intake structure protects native fish,’ says Fiona Crombie, Environmental Manager. “Good design is one thing — proving it works is the next step.”
Early insights from NIWA.
Surveys during the 2024/2025 season recorded six native species and one salmonid around the intake. The species recorded are typical of fish fauna generally found at this distance inland, with the exception of one īnanga:
- Longfin Eel Ōrea (Anguilla dieffenbachii) – most frequently captured across both survey rounds;
- Shortfin Eel;
- Common and Upland Bully, toitoi;
- Canterbury galaxias, kanakana huruhuru;
- Īnanga – one individual recorded, and
- Brown Trout, Salmonids – fewer than five across both survey rounds.
These findings reinforce earlier evidence that the barrier is largely effective at excluding juvenile salmonids. Surveys will continue over coming seasons, strengthening the evidence base and confirming the barrier’s long-term performance.
