Once you have identified the problem, and applied the necessary tools for restoring kōura to your stream, the next phase of your project is to monitor the site to see whether restoration works.
Once you have identified the problem, and applied the necessary tools for restoring kōura to your stream, the next phase of your project is to monitor the site to see whether restoration works.
Monitoring your project is essential for discovering what worked, what didn’t, and what can be changed for future restoration. Many community-based projects are not monitored, and it is possible that while a stream might look better, its kōura population may not have improved. Ideally, a successful monitoring programme should involve before/after kōura surveys.
Kōura surveys should be conducted each year for 3-6 years. Ideally, a summer survey should be carried out each year for at least 3 years before restoration to establish a valid baseline, and then for 3 years post-restoration.
Where restoration is limited to riparian planting, which can take 5-10 years before any major changes are noticeable, post-restoration surveys are best left for at least 5 years. It may also be useful to make comparisons with streams similar to the one you restored.
Methods for carrying out kōura surveys depend on the habitat type. Consult a qualified and experienced freshwater ecologist to determine the best way to monitor your waterway.
Table 1: Summary assessment of stream kōura monitoring/sampling methods trialled in our study.
Method
Pros
Cons
Minnow traps
Widely used method
Suitable for range of habitats
Easy to relocate equipment
Moderate equipment costs
Suitable for a wide range of habitats
High variability between traps
No catch per unit area
Bias towards large male kōura
Use weather dependent
Theft potential
Return trip required
Low catches when eels present
Rama–spotlighting
Traditional fishing method
No specialist equipment
Quick method
Catch per unit area
Weather dependent
Limited to wadeable shallows
Visibility dependent
Biased towards large kōura
Biased towards shallow populations
Kōura abundance only. No size class data or breeding information
Sampling done at night
Low numbers observed when eels present
Electric fishing
Catch per unit area
Samples full size range
Good for sampling fish and other stream invertebrates
Specialist/costly equipment and training
Visibility dependent
High variability between samples
Suitable for shallow streams only
Not very effective in deep, soft-bottomed or weedy habitats
Use weather dependent
Potential harm to kōura and fish
Tau kōura - individual bracken fern bundles
Traditional fishing method
Samples full size range
Large samples
Natural material
Suitable for range of habitats
Unobtrusive
Cheap
No clean-up required
Good for sampling benthic fish and other invertebrates
Catch per unit effort
No catch per unit area
Return trip required
Must be left for at least 2 weeks for kōura to colonise the fern
Prone to displacement by flooding
Fern needs to be available
Low catches when eels present
Fine mesh fyke nets
Widely used method
Suitable for range of habitats
Expensive equipment costs
Suitable for a wide range of habitats
Catch per unit effort
Potential vector for spread of pest plants and fish
