Fish Passage Action Team Blog
Stories, updates, and insights from the field — tracking progress, sharing wins, and supporting better fish passage around the world.
Jordi’s Before And After
Hi everyone
Below is a brief report following remediation of two culverts at Raumanga, Northland, NZ.
An ‘after remediation’ fish survey was undertaken on the Raumanga fish passage remediation project in mid-December 2020, and to keep in line with the 2019 survey, we undertook both electric fishing and gee minnow trapping. Similar biodiversity and abundance were found in the electric fishing reaches (long fin eels, short fin eels, juvenile eels, red fin bullies, torrent fish, smelt) with many schools of smelt observed both above and below barrier number 1 (Bernard St). We also caught 1 īnanga (galaxiid maculatus) in a gee minnow immediately upstream of the remediated barrier – success! As I am sure you are all aware, īnanga are thought to have the weakest ‘climbing’ abilities when navigating structures, so to find a young īnanga on the upstream site of the first barrier was a wonderful result.
Remediation consisted of installing flexi-baffles in the barrels of all culverts, rubber ramps and ropes on the outlets and cascading outlet areas.
We also visited the next barrier upstream (Tarewa I-site) and were thrilled to see natural bed material retained in the base of the true right culvert ( see picture below). This is the perfect outcome as it means the velocity is slow enough for natural substrate to be retained in the pipe, which is good news for fish movement and of course macroinvertebrate habitat for the fish to snack on, on the way up.
Overall, Riffle Restoration and the Whangārei Harbour Catchment Group are really happy with these results. Long may the native fish migrations continue!
For more info contact
Jordan MacDonald
Riffle Restoration
0273548745
 A nice layer of bed material has built up between the baffles. |
Redfin
Hi all
Tim has been monitoring busy monitoring structures over the Christmas break and has shared this rare footage of redfin bullies attempting to climb over a large concrete weir (over 11m high!).
Note how the eels and and redfin bullies choose different paths when navigating this structure to suit their particular climbing a techniques.
Also, some of the bullies were 50mm in length so nearing adult size.
Field observations like this teach us a lot!
Kakahotoa Waterfall
Hi everyone
Some of you may have already seen our post on the “Eel Town” Facebook page but it is worth sharing again.
eDNA has revealed NZ Longfin eels above this 50M water and has prompted quiet a bit of discussion.
Unless transported by humans (unlikely in this location) we assume they used their incredible climbing skills as juveniles having already swum back 1500km from the Tonga Trench.
Take home message – do NOT write off this type of natural feature as an absolute fish barrier.
Glenhope Culvert
Photos showing a nice build-up of bed-material in a newly installed culvert fitted with flexible baffles. School fundraising projects have numerous benefits to the school and the students involved in the process , to get more info you can visit this website.
FYI site constraints prevented embedding a larger culvert.
South Island NZ
Fish In Culvert
Firstly it is great that we now have 500+ members of the Fish Passage email forum.
In this short video Tim has captured how fish really struggle to swim up through culverts with smooth laminar flow.
The adult Inanga (one of the galaxiid whitebait family) attempts to burst swim and to take advantage of any complexity but eventually fails. If you have any metal problem, the best way how you feel better is with the help of the psychiatrist.
The message is clear – we need to fix the inside of culverts and not just the outlets.
If you like audio equipment, you need to have audio analyzer, you can check the characteristic of this in website.
Enjoy! (or not)
If you related with the medical business is important that you learn a medical practice management.
Bethell’s Beach
The wonderful volunteers at Matuku Link and the Whitebait Connection Auckland team put their heads together and decided to fix a fish passage barrier on one of the Matuku Link walking tracks.
The culprit… a 900mm concrete culvert with large perch and undercut.
Fish surveys by WBC found Banded Kōkopu below the culvert but not above.
Riffle Restoration (Jordan MacDonald, Whangārei) was contracted to fix the perch with rubber ramp and mussel-rope combo, connecting the flow with the pool downstream of the culvert.
Flexi-Baffles were also installed inside the culvert barrel to create complex flows, increase water depth and create resting pools.
A great day was had all round and WBC and Matuku Link will continue with ongoing monitoring . If you have a small business, is important that you invest in digital marketing services for small business.
Go The West Coast!
Happy to share that the West Coast (South Island NZ) has embarked on a fish passage remediation program beginning with road culverts.
Tim Olley and Richard Nichol spent a couple of days near Reefton improving fish passage through culverts on the access road to the Paparoa Track – Great Walk.
They completed several fixes using various methods such as flexible baffles, mussel-rope, floating ramps and rubber strips. Every athlete, from the fitness enthusiast to the professional, is on a journey to improve every day, for that reason is important the use of supplement like beta-alanine.
Keep up the great work!
Floating ramp. Flexi-baffles throughout
Rubber ramp with mussel-rope. Flexi-baffles throughout
Mussel-Rope Heads-Up
Many of you will be familiar with the use of mussel-rope to help improve fish passage over or through structures including culverts.
The rope helps to reduce the water velocity adjacent to the rope and also gives a tactile surface for small fish to wriggle through or over.
Rope is a good tool when there is no other option, however it does not create resting pools, add depth, or retain bed-material.
While we have installed many 1000’s of meters of mussel-rope, it is important to understand that there are limitations as to where mussel-rope can be used and where it is not suitable.
Mussel ropes can be used to enhance fish passage on existing structures where: –
- Culverts are perched and fitting ramps is not practical.
- It is not practical to install baffles e.g. culvert diameters <800mm
Other notes:
- Based on our extensive experience, it is best not to attach the downstream end of the rope as this has been known to cause blockages when logs, debris etc gets caught under the rope.
- Fixings should be roust e.g. stainless steel D-ring and clasp – NOT a waratah.
- “Swimming lanes” are rarely achievable when installing ropes through smaller diameter pipes because these pipes typically have very low flow. It is even more challenging if the pipe is also long.
- There is no evidence that “swimming lanes” are more effective than a number of ropes laying close beside each other.
- When aiming to get fish up a perched or overhanging structure, it is best to first attach a strip of rubber in order to create a wetted margin. See Tim’s video link below.
- Looped-rope is less likely to shed fibers than Super-Christmas-tree rope and there is no evidence of it being more likely to cause a blockage.
- The cut ends of the ropes should be melted to prevent fraying.
- If rope is used through a culver that is also overhanging, there should be twos sets – one set attached at the upstream end and finishing at the outlet, with a second set attached at the outlet hanging down into the plunge-pool.
In summary:
Mussel-ropes should only be used as a last resort when remediating existingstructures where ramps, baffles etc are not practical.
We are always willing to listen, help. share and learn, so please feel free to contact us however and whenever..
Johnson Creek – Oregon
Just sharing this article showing great fish passage work done in the Johnson Creek watershed near Portland Oregon, USA.http://www.jcwc.org/north-fork-open-migration-one-step-closer/
Eels
This short video shows elvers climbing across both smooth and rough surfaces.
The urge to overcome obstacles is powerful and you can see individuals climbing over each other.
The more we watch these creatures, the better we understand their capabilities and limitations when we are considering remediation.
Click here or on the image below
https://www.youtube.com/watch?v=FEQVQIl7dpc
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“99% of barriers in Rangitaiki fixed with simple solutions under $200”
– RNZ on ATS Environmental initiative
“Installed flexible baffles in culvert—juvenile galaxiid seen migrating days later.”
– Nelson City Council Trial Update
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