Fish Habitat and Agriculture Practices

Managing our effect on fish habitat

Sediment release in a stream caused by runoff

The Fisheries Act defines fish habitat as "spawning grounds and nursery, rearing, food supply and migration areas on which fish depend directly or indirectly in order to carry out their life processes." It also defines fish to include "parts of fish, shellfish, crustaceans, marine animals and any parts of shellfish, crustaceans or marine animals, and the eggs, sperm, spawn, larvae, spat and juvenile stages of fish, shellfish, crustaceans and marine animals." Under the Fisheries Act it is illegal to harmfully alter, disrupt or destroy fish or fish habitat, unless authorized to do so.

Many common agricultural practices can put both fish and their habitat at risk and may result in a violation of the Fisheries Act, which could lead to enforcement action. However, with proper caution and care, you can avoid these risks and protect fish and fish habitat for future generations.

How does sediment affect fish habitat?

Before: Effect of sedimentation on a stream bottom and fish eggs deposited in the area. After: Effect of sedimentation on a stream bottom and fish eggs deposited in the area.

Sediment, sand or silt can negatively affect fish and fish habitat in a number of ways including:

  1. Reduction in visibility making it difficult for fish to locate and capture prey.
  2. Damage to fish gills causing injury, mortality and increased susceptibility to disease.
  3. Infilling of sediments in pools and riffles which can smother eggs and reduce the quality of spawning and rearing habitat.
  4. Reduction in food supply by displacing or destroying insect larvae found in bottom  areas.

You can protect fish habitat against sediment

Avoid crossing water bodies with farm equipment

Damage caused by improper fording techniques.

Motorized vehicles crossing streams and rivers, a practice known as fording, can introduce sediment and other contaminants into fish habitat. Motorized equipment can also compact bottom soil in streams and rivers, affecting the quality of the fish habitat and its ability to sustain life. Fisheries and Oceans Canada encourages you to avoid the practice of fording streams and rivers in farm equipment and suggests the use of existing access roads and stream crossings (e.g. culverts, bridges, etc.). If fording is unavoidable, please contact your local area habitat biologist. Remember, in addition to federal legislation, you are required to respect all provincial and municipal legislation that may be applicable.

Keep livestock away from streams

All streambank areas should be protected against livestock access. Although a streambank may be able to withstand the weight of a human, it is unlikely that it can survive the repeated movement of livestock. When livestock repeatedly access streambanks, the surrounding ground can give way and release sediment into the stream. If access is required for water supply, then efforts should be made to limit the access to a single stabilized area. Any damage caused by livestock should be repaired as soon as possible to ensure that the structure of the streambank is maintained.

Respect and maintain buffer zones

Illustration of a well-maintained buffer zone.

A buffer zone is a natural border of vegetation that is left around bodies of water when land is cleared. This natural vegetation acts as a filter by reducing the movement of sediment, pesticides, nutrients and fertilizers into water. In addition, a buffer zone aids in stabilizing the bank and provides shading and a food supply for fish. The width of a buffer depends on a variety of factors including soil characteristics, slope and the type/quality of fish habitat being protected. For further information, please consult the document, Best Management Practices for Riparian Zones in Newfoundland and Labrador.

Practice streambank stabilization activitie

Rip Rap used to stabilize a streambank.

Whether the cause is the activity of humans, animals or nature, sometimes streambanks require stabilization. An unstable streambank can lead to the release of sediment into streams. A complete streambank collapse could harm or destroy the fish habitat in a stream or river.

An unstable or eroding streambank can change stream flow. This change can divert a stream into adjacent farmland, causing subsequent erosion and damage to fields. It is important to avoid contributing to the erosion of streambanks. You can ensure that any unstable streambank areas are stabilized by adhering to the following:

  1. Re-vegetation is the ideal method of bank stabilization.
  2. Rip rap (angular rock) used to stabilize streambanks should be clean and free of fine materials and be of sufficient size to resist movement during flood events.
  3. Gabion baskets (rock filled metal cage/basket) can be used in areas where rip rap is not suitable because the slopes are not at a stable angle.
  4. Stabilization should not result in a reduction in stream width.
  5. Stabilization material should be placed from the toe of the bank to the anticipated high water level or to the top of the bank slope.
  6. All stabilization activities should be completed in the dry.
  7. Contact your local area habitat biologist for advice on streambank stabilization.

Be aware of other contaminants that can affect fish habitat

Manure and fertilizer application

The improper use of manure and fertilizers can have negative effects on fish and fish habitat. These materials can reach water bodies through runoff and can lower the quality of water. The introduction of such materials can result in an excessive growth of algae that is caused by increased nutrient levels found in fertilizer and manure. Points to keep in mind when dealing with manure and fertilizer include:

  1. Manure and fertilizer should be properly stored in adequately sized facilities away from bodies of water.
  2. Use only the minimum amount required by crops to reduce runoff.
  3. Manure should not be spread on frozen or snow covered ground or flood-prone areas.
  4. For further details on the management of manure and fertilizer, please consult the Environmental Farm Practices Guidelines.

For further information regarding any of the topics discussed here or any other issues regarding the protection of fish and fish habitat, please contact your local area habitat biologist.

Area Habitat Biologist - Central
Fisheries and Oceans Canada
4A Bailey Street, Suite 200
Grand Falls-Windsor, NL A2A 2T5
Tel: (709) 292-5197
Fax: (709) 292-5205

Area Habitat Biologist - Eastern
Fisheries and Oceans Canada
1144 Topsail Road
Mount Pearl, NL A1N 5E8
Tel: (709) 772-5597
Fax: (709) 772-2659

Area Habitat Biologist - Southern
Fisheries and Oceans Canada
1144 Topsail Road
Mount Pearl, NL A1N 5E8
Tel: (709) 772-7345
Fax: (709) 772-2659

Area Habitat Biologist - Western
Fisheries and Oceans Canada
1 Regent Square
Corner Brook, NL A2H 7K6
Tel: (709) 637-4349
Fax: (709) 637-4445

Area Habitat Biologist - Labrador
Fisheries and Oceans Canada
202 Kelland Drive
Goose Bay, NL A0P 1C0
Tel: (709) 896-6151
Fax: (709) 896-8419

DFO/2008-1381
Cat. No. Fs114-11/2008E
ISBN: 978-0-662-47883-6