Access to Spawning Sites

Hi everyone

Fish need to have access to spawning sites.

Here is a link to a really nice video showing stage-one of a manmade spawning and nurturing site for inanga (galaxiid maculatus) though many other species with make this place home.

The pools will soon be planted and connected to the main canals leading to the Little Waihi estuary.

Twice daily tides will flush the ponds and provide the potential for spawning each autumn. 

This project is being led and funded by the Bay of Plenty Regional Council.

Pukehina/Pongakawa, Bay of Plenty NZ

Culvert Webinar

Upcoming Relive LIVE:
Learn How to Maintain Hydraulic Capacity of Culverts & Protect the Fish
Thursday, April 29th @
8:30am PT / 11:30am ET (USA).
Note this time may not suit so we will post a link to a recording once done.
Learn how installing flexible culvert baffles is an easy and inexpensive method to improve fish passage through culverts. Salmon, trout and other fish and aquatic species are often blocked from their habitat by poorly designed or constructed culverts. Repairing or removing culverts is costly and requires considerable time and resources. SSA Environmental LLC has developed culvert baffles that improves fish passage in an effective and economic manner.
Register Here

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

A nice layer of bed material has built up between the baffles.


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)

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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