Hello everyone,
Tasman District Council (NZ) continues to be a world leader in region-wide fish passage remediation programmes. Tasman has remediated thousands of fish barriers using a range of cost-effective methods. Two of the most commonly used are flexible rubber ramps and floating ramps to overcome perched culverts.
Both ramp types were monitored by Olleycology Ltd along with Cawthron Institute during the spring whitebait run of 2024, to evaluate their effectiveness for different native fish species. This report documents three field studies conducted in the Tasman Region.
What We Found:
- Flexible rubber ramps were highly effective for climbing species like banded kōkopu and elvers.
- Floating ramps were more effective for swimming species like īnanga and redfin bully, particularly in round culverts and at higher perch heights.
- Combining both ramp types may offer the best solution for mixed fish communities.
Why It Matters:
The report also shows that low-cost remediation methods can be very effective.
These findings provide evidence-based guidance for selecting remediation approaches based on target species, culvert type, and site conditions – supporting catchment-scale fish passage restoration programmes.
Watch this space – more monitoring of the ramps and reports are in the pipeline.