What We Do
Fish need to move. They need connections between and within waterways during various life stages to reproduce, feed, and contribute to their ecosystems by recycling the nutrients they take in. Each year millions of fish migrate between the ocean and their native habitats to spawn. Some fish move within a river system to find food or refuge from warmer water. Other aquatic wildlife, like mussels, also depend on the ability to move from place to place to survive.
What is fish passage?
Fish passage is the ability of fish or other aquatic species to move throughout an aquatic system among all habitats necessary to complete their life cycle. We can restore fish passage by removing in-stream barriers or replacing them with structures that allow fish to pass. When fish and other aquatic species can’t migrate or have access to important habitat, they can’t reproduce and build sustainable populations. Some populations are so affected by barriers that they are listed as a threatened or endangered species or may even become extinct. Atlantic salmon is just one example of a species that has been severely impacted by instream barriers. Once plentiful and found in almost every river north of the Hudson River, today only a small percentage of their historic population remains. One major cause of their decline are the numerous barriers that prevent these fish from reaching important upstream spawning habitat.
Fish passage benefits more than fish.
Improving fish passage is good for fish, and for people too. By allowing rivers to flow naturally, barrier removal can help manage and reduce flooding. Removing barriers like dams that are potential hazards makes the waterways safer and can increase boating opportunities. Replacing road stream crossings with structures that can better withstand storms brings economic benefits to local communities, as these structures are less likely to blow out in floods and need less maintenance.
Another barrier removal benefit includes building sustainable fish populations that improve recreational and commercial fishing. Some fish that benefit from barrier removals, such as the Eastern brook trout, are key to the recreational fishing industry and associated tourism. Other fish, like the migratory river herring, are prey for larger commercial and recreational species. The commercial and recreational fishing industries support more than 2 million jobs and generate billions in sales each year in the U.S.
Barrier removal also improves lives of tribal cultures like those along the Klamath River Basin in California and Oregon. The salmon that migrate in the Klamath are the source of the tribe’s food, income, and are at the heart of their cultural heritage and identity. There have been recent cases where tribes have not been allowed to fish their ancestral waters because of decreases in fish populations, which are due in part to the presence of dams and other barriers.
What are fish passage barriers?
A barrier is anything that prevents or reduces the ability of aquatic species to move where needed to survive and complete their life cycle. This includes physical barriers, such as dams, culverts, and levees, and environmental barriers such as excess sediment, poor water quality, and temperature or flow variations.
Examples of fish passage barriers:
- Culvert: Culverts are structures that allow water to flow under a road, railroad, trail, or similar waterway obstruction. An undersized or improperly placed culvert can impede or totally block fish and aquatic species from passing.
- Dam: Dams are physical structures running the width of a river system to capture or impound water. Some fish species are very poor jumpers and cannot get past even low height dams.
- Levee: Levees are earthen low ridges or embankments along the edges of a stream or river that impede flooding of adjacent land. Levees often cut off access to wetland areas that are critical to many aquatic species.
- Sediment: Increased deposition of sediment in waterways changes the habitat and of the area and can result in the habitat becoming unpassable for an aquatic species. Increased suspended sediment in a waterway can also affect species’ ability to pass through an area.
- Temperature: Aquatic species are sensitive to changes and extremes in temperatures. Abnormal increases or decreases in water temperature can prevent movement of fish.
- Water diversion: Water diversions are structures that redirect water from a stream for another purpose, such as agricultural use. These structures can be harmful to fish if the fish are redirected along with the water onto the agricultural lands or if the fish become caught on the water intake structure. Water diversions often also reduce the amount of habitat available to aquatic species by reducing the amount of water available in the stream.
- Water flow: High velocities or lack of water flow can be a barrier to fish passage.
- Water quality: Some aquatic species are sensitive to poor water quality conditions, such as low oxygen levels or high levels of contaminants. Fish may not be able to survive in or migrate through an area with poor water quality.
What is a fish passage project?
A fish passage project is any activity that improves the ability of fish or other aquatic species to move by reconnecting habitat that has been fragmented by a barrier.
Examples of funded projects include:
- Culvert replacement
- Dam removal
- Water diversion
- Natural rock ramps
- By-pass channels
- Low water crossings
- Fish passage training
- Levee breach
- Inventories and assessments
The National Fish Passage Program improves community infrastructure resilience, rebuilds fish populations, improves recreational and commercial fisheries, and restores the beauty of free-flowing waters. We provide financial and technical assistance to support projects that improve fish passage.
Project proposals may be initiated by any individual, organization, government, or agency, in cooperation with their local Fish and Wildlife Conservation Office. Contact a Fish Passage Coordinator in your area or contact your local Fish and Wildlife Conservation Office, to discuss the project and learn more about the technical assistance that is available.
Technical and Planning Assistance
U.S. Fish and Wildlife Service biologists and engineers are available to provide assistance in the planning, design, implementation, and monitoring of select fish passage projects.
Fish Passage Engineering
Experienced civil and hydraulic engineers working in the fields of fish passage and protection can provide technical assistance in the planning, design, and evaluation of projects to improve conservation outcomes.
The National Fish Passage Program provides funding to support fish passage projects You must work with a Fish and Wildlife Conservation Office Biologist to be considered for funding. To begin this process, please contact your Regional Fish Passage Coordinator or your local Fish and Wildlife Conservation Office.