In the past year, significant steps have been taken to improve native fish migration within the Te Hoiere catchment, thanks to the dedicated efforts of our team and community partners.
One of the highlights was the installation of the first project-supported culverts in Linkwater. Around 30 people gathered to witness this event, marking an important milestone in enhancing fish migration pathways. The culverts, measuring 1.5 metres in diameter, were installed and assessed for fish passage on the Frost dairy farm in Linkwater.
At this event, other options for improving fish passages such as ramps and spat ropes, were also discussed. These alternatives can improve existing structures, helping native climbing fish access areas of our waterways isolated by man-made structures. Without barriers, fish are free to migrate as needed, supporting the two threatened and seven at-risk native species found in our catchment.
This upgrade on the Frost’s farm is a vital improvement in the movement of fish to and from the Mahakipawa Arm and has since been done again on two more farms within the catchment.
Prior to the culvert installation, Marlborough District Council scientists conducted surveys and identified several native freshwater fish in the area, including common bullies, shortfin eels, inanga, and freshwater shrimp. This discovery shows how important it is to remove barriers to ensure these species can complete their life cycles, which involve both freshwater and saltwater environments.
The Te Hoiere Project, guided by the Fish Passage Action Plan from the National Institute of Water and Atmosphere (NIWA), has been actively working to identify and address barriers to fish migration in the catchments. These barriers, including improperly sized culverts, can significantly impede the movement of fish that need to migrate to the sea to spawn or mature.
Inadequate culvert design—such as any overhangs—can disrupt upstream travel, particularly for species that depend on low-flow conditions to ascend to suitable habitats. Simple adjustments like relocating culverts are cost-effective alternatives to full culvert replacements and can significantly enhance fish passage by replicating natural stream conditions.
To combat these issues, our approach has focused on sizing culverts appropriately for floodwaters, replicating natural stream gradients, and including natural substrates inside the culverts. Additionally, the installation of spoiler baffles and spat ropes have been used to enhance fish passage by reducing water velocities and providing necessary resting areas for the climbing species.
Further funding is now available for landowners looking to replicate this work on their farms. If you have culverts that need replacing or would like to look into alternative solutions to ease fish migration and would like to know more about how you can access the funding to get this done, apply for funding today.
Remediation through the Project can include support with:
- New culverts
- Spat ropes
- Spoiler baffles
- Rock ramps
- Fish ramps
- Culvert alternative
