Fish and Taonga Species Distribution Survey
Pictured above: freshwater fish, tuna and kōura found during the fish distribution survey
Joint venture helps understand freshwater fish habitats
Monitoring is being used by Te Hoiere Project to increase our understanding of native species and habitats. This monitoring will help to guide future direction and activities within the project. During a collaborative monitoring planning workshop in September 2023, project partners identified understanding fish and taonga species distribution as a priority. This monitoring builds on a previous Department of Conservation survey from 2020 – 2022 (link to info on website – if we have the report on the website).
Working with project partners, the Department of Conservation, Marlborough District Council, Ngati Kuia, and consultants Olleycology were engaged to provide technical field support. The Olleycology team also provided training to project team members to ensure consistency across sampling techniques and data collection.
Initial planning identified 19 sites across Rai, Te Hoiere and Whakamarino sub-catchments however due to a particularly dry summer, finding flowing water in lower stream order sites proved challenging, leading to the decision to survey one less site than planned.
Site selection and survey execution
A list of proposed survey sites was initially compiled by DOC and reviewed by MDC's science team to assess their suitability and accessibility. Following this, MDC contacted landowners to seek permission for access to private land. In instances where permission was denied or landowners were unreachable, alternative sites were selected.
Out of the 19 initially planned sites, 18 were surveyed across the Rai, Te Hoiere, and Whakamarino sub-catchments. Due to a particularly dry summer, finding flowing water in lower stream order sites proved challenging, leading to the decision to survey one less site than planned.
Survey methods
The survey employed a combination of methods:
- eDNA sampling for all sites to detect genetic material from aquatic species.
- Electric fishing in selected stream sections, following national protocols.
- Rapid Habitat Assessment to evaluate environmental conditions at each site.
Preliminary findings
Preliminary results were compiled to share insights with participating landowners and community members. The species identified during the 2024 survey include:
- Kaharore bully
- Bluegilled bully
- Common bully
- Redfin bully
- Torrent fish
- Dwarf Galaxias
- Longfin eel
- Shortfin eel
- Banded kokopu
- Koaro
- Inanga
- Brown trout
- Rainbow trout
- Smelt
- Koura
- Kākahi
Electric fishing and eDNA analyses confirmed the presence of these species, which are characteristic of the Te Hoiere River catchment, across all but two sub-catchments. Notably, the Tinline and Dead Horse Streams exhibited lower species diversity than expected.
Interestingly, smelt which are usually found at low elevations, were found in the Tinline Stream and eDNA detected a weak signal for the speckled longfin eel, an Australian migrant that is a relative of New Zealand's native eels. In the Dead Horse Stream, only kōura and longfin eels were detected, despite pristine habitat conditions. Due to the steep and rocky terrain, there is likely a fish passage barrier downstream. While the stream offered excellent habitat, it wasn't easily accessible.
The presence of kanakana (lamprey) at specific sites, confirmed by both electric fishing and eDNA, aligns with findings from a detailed pheromone survey conducted this summer.
Habitat and ecological health assessments
Habitat assessment scores ranged from 41 to 95 (with 100 being the highest possible score), indicating variable habitat quality across sites. Higher scores were generally found in upland streams surrounded by native forest, while lower scores were associated with farmland streams lower in the catchment.
The survey data has been added to the NZ Freshwater Fish Database, with eDNA results accessible on Wilderlab's Explore page. Further analysis and detailed reporting of the findings will be undertaken by DOC in the 2024-2025 fiscal year.
Explore further
Community and project partners are encouraged to explore eDNA results on Wilderlab's Explore page, offering insights into the aquatic biodiversity within the Te Hoiere catchment and informing ongoing efforts to improve waterway health.
