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.

Kakahotoa Waterfall – Bay of Plenty, NZ

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

Before – Flexible baffles were installed to ensure fish passage and help retain bed material.
After – A few weeks later bed material has naturally accumulated

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

Here is Jordie going the extra mile to restore fish passage.

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.

Fitting the rubber ramp and mussel-rope to help climbing species

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!

Tim Olley,
Floating ramp. Flexi-baffles throughout
Richard Nichol,
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:

  1. 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.
  2. Fixings should be roust e.g. stainless steel D-ring and clasp – NOT a waratah.
  3. “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.
  4. There is no evidence that “swimming lanes” are more effective than a number of ropes laying close beside each other.
  5. 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.
  6. 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.
  7. The cut ends of the ropes should be melted to prevent fraying.
  8. 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..


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

Nelson City Fish Passage Restoration Program

Here in NZ it was Conservation Week last week.

Barriers to Fish Passage, is certainly making the headlines, particularly with the announcement of the National Policy Statement Freshwater Management (NPS-FM 2020).

Nelson City, NZ has been ahead of the game, with a region-wide program well underway, remediating a range of structures with effective, robust, and low-cost fixes.

The city council has posted this excellent short video highlighting some of the work completed so far.

Conservation Week – Helping our native fish swim against the current

It’s #ConservationWeek and here’s today’s conservation video. This video shows how concrete pipes and culverts make it hard for native fish to swim up and down our streams so we have to put in deflectors to slow the current down and make places for them to rest. That helps them swim upstream to spawn and keep their populations healthy. Comment on this video and you will go into the draw to win a family pass to The Brook Sanctuary.

Posted by Nelson City Council on Thursday, 20 August 2020

 The NCC fish passage program is very simple  – see below:

1. Locate structures in the waterway
2. Survey of structures in waterways and give a “Current Status”
3. Identify barriers to fish
4. Consider desired and undesired fish species
5. Propose mitigation and costs
6. Propose some form of prioritisation for remedial works
7. Undertake remedial works
8. Reporting and data management
9. Ongoing monitoring

Another YouTube version of the video below.