7 key tips for a fish friendly farm

Native fish need shelter, clean water, food and room to move. Below are seven actions you can do to benefit native fish life in the streams on or near your farm. When performed in association with each other they can also improve water quality, stabilise stream banks and reduce erosion, increase farm productivity, improve farm infrastructure, reduce stock loss, increase stock health and improve the value of your farm.

1. Have large woody debris (snags) in your streams

Large woody debris provides one of the most important habitats for fish within a river or creek. In some cases, numbers of native fish in a waterway are often directly related to the amount of wood. Large woody debris provides protection from predators, shelter from direct sunlight, resting areas out of the main channel flow, territorial markers, breeding sites and foraging sites. Large wood in streams can also increase bank stability and reduce waterway erosion.

Image: Large woody debris and healthy riparian zones provide a range of habitat for terrestrial and aquatic animals

What you can do:

  • Let ‘sleeping logs lie’ wherever possible
  • Seek advice from I&I NSW (Fisheries) if a large piece of wood is causing a problem
  • Modify wood by lopping, realigning or moving in preference to removal
  • Consider ‘re-snagging’ if your waterway is free of large woody debris, because the wood can provide immediate benefits to fish. Consult with I&I NSW (Fisheries)
  • Re-establish native riparian vegetation to ensure a future source of large woody debris

2. Grow native vegetation on the stream banks (riparian area)

Fish and other aquatic species prefer streams with good riparian vegetation because the plants:

  • provide food in the form of fruits and terrestrial insects, shelter, shade, fine organic material
  • are a source of large woody debris and filter sediment, phosphorus and organic nitrogen from run-off

Exotic vegetation such as willows, invade stream banks and exclude native vegetation, changing the structure and function of the riparian zone, creating a poor habitat for native fish. Willows are deciduous, dropping their leaves all in one go. This alters the timing and quality of organic inputs in the stream, causes wide temperature variations and reduces the amount of shade and protection.

Image: Densely vegetated stream banks shade the waterway and help to control water temperature

What you can do:

  • Control stock access to waterways and limit grazing in riparian areas
  • Revegetate riparian areas in layers with a mix of species native to your area
  • Control weeds during regeneration
  • Maintain a well-vegetated buffer area (grass margin) between cropland and riparian areas
  • Eradicate willows and other exotic plant species
  • Work with your neighbours to prevent re-infestation from an upstream source

3. Install fish friendly crossings

Many freshwater fish species are migratory and must move between a variety of habitats to complete essential life history stages. Even a small structure such as a concrete causeway or a pipe culvert can create a barrier such as a small waterfall or shallow flow depths and restrict fish movement. Vehicles and stock traversing waterways on ford-type ‘wet crossings’ can stir up sediments, cause erosion and increase turbidity. Cows are 50 times more likely to defecate when crossing a stream in-stream than on a raised crossing1. Manure increases organic nitrogen, suspended solids and pathogens, and reduces water quality.

Image: When this large celled crossing replaced a small-piped causeway it improved fish passage and water flow, and provided a safer, more reliable crossing for the landholder

What you can do:

  • Always seek advice from I&I NSW
  • (Fisheries) on fish friendly designs and permits
  • Modify or remove structures which are barriers to fish
  • Include a fish ladder or suitable passage for fish (bridges and arch structures have the least impact) in new crossing designs
  • Minimise the use of causeways
  • Set culverts at bed level and include a low flow channel. Cells should have a minimum water depth of 0.2-0.5 metres
  • Avoid locating bridge foundations and piers within the main waterway channel
  • Remove debris from around the crossing

4. Control or treat agricultural run-off

Run-off from agriculture can be a source of sediment, nutrients, pathogens, pesticides and sediment-bound pollutants. Pesticides are suspected of causing a number of fish kills in NSW over the past 20 years.

Pesticides can affect fish by:

  • reducing reproductive success and life expectancy
  • increasing the incidence of abnormalities
  • causing skeletal defects and growth reductions

Suspended sediments in waterways (turbidity) can smother fish eggs, clog gills, and increase stress levels and disease.

Deposited sediment can smother whole stream beds, filling in important breeding and refuge sites such as deep holes, reducing available habitat and increasing the input of sediment-bound pollutants.

Image: This farmer ponds and distils farm run-off, before spreading the ‘polished’ by-product on the paddocks

What you can do:

  • Ensure riparian areas are well planted with native vegetation
  • Use chemicals such as pesticides conservatively, and apply with care especially near waterways
  • Support the use of biologically sensitive herbicides and pesticides (ask I&I NSW for options)
  • Protect riparian zones and buffer margins from stock and vehicles
  • Retain and protect wetland areas as they play a valuable role in filtering runoff
  • Establish a series of filter ponds for horticultural and nursery runoff
  • Use sediment traps, drop boxes or artificial wetlands to filter or ‘polish’ runoff from cleared or disturbed land
  • Consider sealing gravel roads and unsealed tracks

5. Provide water for stock offstream

When stock drink directly from streams they reduce water quality, cause bank and stream bed erosion, destroy riparian vegetation, stir up sediments and cause the loss of habitats for fish and other wildlife. Cattle defecate 25% of the time when drinking, 1kg of phosphorus from manure can result in the growth of up to 500 kg of algae2. These algal blooms can choke waterways and may be toxic to fish, other aquatic life, livestock and people.

Image: Animal waste contaminates waterways and transmits disease-causing bacteria to livestock, humans and fish. Clean water is vital to the health of your stream. Image credit: NSW Department of Primary Industries.

What you can do:

  • Provide a number of off-stream watering points. Studies have shown that even without fencing, stock prefer to drink clean water from a trough even if they have access to stream water1
  • Pipe from an existing supply or pump water from a bore or waterway to troughs in the paddock. If complete restriction is not viable, manage stock access with limited, carefully considered drinking points

6. Control the opening of floodgates

Floodgates prevent flood waters and tidal water inundating low lying coastal floodplains. However, permanently closed floodgates can:

  • reduce water quality and encourage in-stream weeds
  • prevent fish passage to important breeding and feeding grounds fragment and alienate aquatic populations
  • fragment and alienate aquatic populations
  • create stagnant conditions favoured by pests such as mosquitoes
  • enhance the effects of acid sulfate soils, increasing water acidity

Acidic drainage water can:

  • directly cause fish kills
  • damage fish skin, increasing invasion from infections and diseases such as ‘red spot’
    cause juvenile fish to avoid certain habitat
  • damage fish gills, reducing oxygen intake and regulation of salt and water
  • stunt the growth of oysters and cause their shells to breakdown
  • fragment and alienate aquatic populations

Image: “User-friendly” tidal floodgates reduce drain management time, improve water quality and enhance fish passage. Image credit: NSW Department of Primary Industries.

What you can do:

  • Modify floodgates to allow exchange with estuarine water during non-flood periods.Designs include sluice gates, tidal floodgates and winch gates. Consult with I&I NSW (Fisheries) for advice and approvals
  • Make the opening as large as possible to maximise fish passage and reduce the force of the current flowing through the opening
  • Use automatic gates operated by tidal flow wherever possible as these maximise fish passage
  • Make your drains shallower; shallow dish drains (0.3 m depth) minimise the potential of disturbing acid sulfate soils. Seek advice from I&I NSW (Fisheries)

7. Protect your wetlands

Wetlands are low-lying areas inundated with water on a temporary or permanent basis. These areas have many important ecological functions. They filter sediments and sediment-bound pollutants from water before it drains into the main waterway. Wetlands also provide essential feeding, breeding and nursery habitats for many fish species and release nutrients and stored carbon, the basis of aquatic food chains.

Image: Healthy wetlands support a diverse ecosystem, and provide essential habitat for migratory birds, juvenile fish and other animals. Image credit: NSW Department of Primary Industries.

What you can do:

  • Revegetate wetland areas that have been cleared, using native species
  • Fence stock out of wetland areas, and only use them for grazing in droughts
  • Modify water retention devices (eg floodgates) to mimic natural flow regimes
  • Identify acid sulfate soil areas and seek advice on their management
  • Use re-established wetlands as a filter for farm run-off

1 Davies-Colley, R.J., et al. (2004) Water quality impact of a dairy cow herd crossing a stream. New Zealand Journal of Marine and Freshwater Research 38: 569-576.

2 Fitch, L.B., et al. (2003). Caring for the Green Zone: riparian areas and grazing management – 3rd Edition. Lethbridge, Alberta: Cows and Fish Program

All images directly supplied by or reproduced by The Australian River Restoration Centre or Rivers of Carbon, with permissions from the copyright owner(s), unless stated otherwise.

Download a copy of the full fact sheet

Do you need some help in making your farm fish friendly?

Visit the NSW Department of Primary Industries website for more information.

Handy Guide: Tax deductions for Landcare, riparian and similar expenses for primary producers

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