Measures to avoid and mitigate risks to fish and fish habitat

June 2026

The Fish and Fish Habitat Protection Program developed standardized general avoidance and mitigation measures to help proponents prevent harmful impacts to fish and fish habitat.

The measures are categorized by the 6 most common pressures (or types of risk) caused by projects in or near water. The measures are presented in a hierarchical structure that prioritizes avoidance measures first, followed by mitigation measures where necessary. They can be built upon by adding project-specific measures in a project plan. Other best practices are also available to prevent the deposit of deleterious substances.

Using standardized measures can make the project planning process more efficient by:

• reducing efforts on the routine elements of the project
• focusing efforts on the parts that are more complex and unique

Proponents are responsible for determining what standardized and site-specific measures are needed to avoid or mitigate risks to fish and fish habitat.

Once you’ve determined which measures apply to your project, check if your project needs a review.

Standardized measures

Death of fish

Avoidance measures

• Avoid killing fish by means other than fishing.
• Avoid using explosives in or near water.

Mitigation measures

• Carry out the project in accordance with timing windows, if water is present.
• Limit the duration of in-water works, undertakings and activities.
• Capture fish trapped within an isolated or enclosed area and relocate them to the same watercourse or water body.
• Dewater gradually to reduce the potential for stranding fish.
• Capture and relocate any fish as per applicable permits.
• Reduce impingement and entrainment of fish from water intakes when in operation.
• Reduce noise and energy during all phases of the project.

Changes to fish passage

Avoidance measures

• Avoid changing flow or water level.
• Avoid obstructing or interfering with the movement and migration of fish.

Mitigation measures

• Maintain fish passage during all phases of the project.
• Maintain hydrodynamic and hydraulic conditions (meaning, flow) during all phases of the project.

Changes to the riparian zone

Avoidance measures

• Use existing trails, roads, access points or cut lines.

Mitigation measures

• Maintain a functioning vegetated riparian zone.
• Limit vegetation removal, pruning, and grubbing to the area required for accessing the project site.
• Limit access to shorelines and banks or areas adjacent to the watercourse or water body.
• Construct roads, access points and approaches perpendicular to the watercourse or water body.
• Use methods to reduce soil compaction (for example, swamp mats, pads).
• Reinstate slopes of the affected riparian zone.
• Re-vegetate the affected riparian zone with native species suitable for the project site.

Changes to habitat structure and cover

Avoidance measures

• Avoid conducting any works, undertakings, or activities in water.

Mitigation measures

• Limit disturbance of fish habitat features (for example, aquatic plants, rocks, woody material) to the area required to carry out the project.
• Operate machinery on land, from barges or on ice during all phases of the project.
• Limit operation of vehicles and machinery to the area required to carry out the project.
• Maintain natural flow and seasonal flow of water during all phases of the project.
• Restore the bed and banks, gradient and contour affected by the project.

Changes in sediment concentration

Avoidance measures

• Avoid introducing sediment in the water (for example, silt, clay, and sand).

Mitigation measures

• Develop an erosion and sediment control plan for all phases of the project.
• Implement an erosion and sediment control plan for all phases of the project.
• Install erosion and sediment controls prior to beginning the project.
• Install erosion and sediment controls to manage sediment laden water during all phases of the project.
• Regularly observe the watercourse or water body for signs of suspended sediment during all phases of the project.
• Take corrective action when and where required.
• Inspect the erosion and sediment controls regularly during all phases of the project.
• Repair the erosion and sediment controls during all phases of the project.
• Operate machinery on land in stable areas.
• Use biodegradable materials for erosion and sediment controls whenever possible.
• Dispose of, and stabilize, all excavated material above the ordinary high water mark or top of bank of nearby watercourses or waterbodies.
• Use clean materials free of fines (for example, silt, clay or sand).
• Pump sediment laden water into a vegetated area or filtration system (for example, settling basin).
• Release water gradually when suspended sediment has settled in the settling basin and water is clear.
• Conduct all phases of the project in isolation of open or flowing water.
• Keep the erosion and sediment controls in place until all disturbed ground has been stabilized and suspended sediments have settled.
• Remove all erosion and sediment controls (unless biodegradable) once the site has been stabilized.

Changes to wetted area

Avoidance measures

• Avoid any temporary or permanent increase in existing footprint below the ordinary high water mark.

Mitigation measures

• Not applicable

Environment and Climate Change Canada is responsible for the administration and enforcement of the Fisheries Act pollution prevention provisions dealing with the deposit of deleterious substances into water frequented by fish. The following best practices can help to prevent the deposit of deleterious substances. In the event of a spill refer to the projects near water website.

Deposit of deleterious substances

Best practices

• Develop a plan to prevent deleterious substances from entering a watercourse or water body.
• Maintain all machinery on site in a clean condition and free of fluid leaks.
• Wash, refuel and service machinery in such a way as to prevent any deleterious substances from entering a watercourse or water body.
• Store fuel and other materials for the machinery in such a way as to prevent any deleterious substances from entering a watercourse or water body.
• Plan activities near water such that materials (for example, paint, primers, blasting abrasives, rust solvents, degreasers, grout, poured concrete, foam, or other chemicals) do not enter a watercourse or water body.
• Ensure that building material used in a watercourse or water body has been handled and treated in a manner that prevents the release or leaching of deleterious substances into a watercourse or water body.
• Dispose of all waste materials on land in a designated area away from the ordinary high water mark of any watercourse or water body.
• Stop work and implement a response plan immediately in the event of a spill of a deleterious substance (including sediment).
• Report spill immediately when a deleterious substance enters a watercourse or water body.
• Use an emergency spill kit.
• Contain water with deleterious substances.
• Clean-up and dispose of water contaminated with deleterious substances.