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.
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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
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
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..
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.
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.
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
I had a great day out in the field with a bunch of folk keen to do some learning with gumboots on.
Kelsey Tills of Rayonier kindly organised the day with representatives from Forestry (Rayonier and PF Olsen), local government (Waikato Regional Council), contactors and a community care group.
Despite the rain, we manged to visit a number of culverts and discussed both new installations and remediation of existing structures, with a view to improving fish passage.
The Fish Passage Action Team are happy to assist and or lead workshops or training days.
Fish Passage Workshop – Whangamata,NZ. Photo – Glenda Betts
Note: This culvert is under a road that crosses a wetland – there is no stream as such, just what was excavated during the installation.
It is worth remembering that lows flows and shallow water are challenges to migrating fish. The video below represents remediation to an upgraded urban storm water pipe serving a small tributary of the Maitai River near Nelson, NZ.
The upgrade involved upsizing the pipe and removing the perch at the outlet.
– Base flows of the tributary are approximately 1L/S – Pipe length 300M – Pipe gradients range from 2%-12%
You will see an increase in the depth and width of the water along with bed-material beginning to accumulate.
Tim Olley captured this rare footage of a juvenile redfin bully (Gobiomorphus huttoni) climbing up a retro-fitted mussel-rope with backing, into an overhanging culvert.
It reminds us that, given half a chance, many fish will navigate challenging obstacles.
What is not well understood, is what precise factors cause a fish to transition from a swimming to a climbing mode of locomotion.
