Fish Passage

Removing dams or installing fish lifts allows migratory fish to return to upstream habitats and lets resident fish move freely throughout the region's rivers.

Use the map above to learn about projects that have opened streams to the movement of migratory fish.

Fish Passage

The removal of dams other barriers from streams across the watershed allows shad, herring and other migratory fish to move between fresh- and saltwater habitats, which is critical if these fish are to reach their historical spawning grounds. From 1988 through 2019, the Fish Passage Workgroup opened 12,071 stream miles through dam removal projects and 19,242 stream miles through fish passage projects. Opened stream miles in mainstem or large rivers, tributaries and headwater streams have benefitted migratory and resident fish.


Miles of rivers and streams opened to fish passage between 1988 and 2019 via fish passage projects and dam removals.

The removal of dams, undersized culverts and other barriers from streams across the watershed allows migratory fish, such as shad and river herring, and residential fish, such as brook trout, to move seasonally between habitats, which is critical for fish to reach their historical spawning grounds. In fact, the abundance of some of these species in the region depends on streams that are open to their movement.

In 2016, the Fish Passage Workgroup reached their 2025 goal to open an additional 1,000 stream miles, established in the 2014 Chesapeake Bay Watershed Agreement. After requesting public feedback, the Principals’ Staff Committee (PSC), in January 2020, approved an outcome modification proposed by the Fish Passage Workgroup. The modification is more consistent with the best available science and establishes a new target to open an additional 132 stream miles every two years to fish passage.

Featured Highlights by State:

  • Virginia: In Virginia, migratory species including alewife, blueback herring, hickory shad, and American shad have been documented in the Rappahannock five miles upstream of the Embrey Dam site since its removal in 2004. In addition, American Shad, Blueback Herring and Striped Bass have been documented as far as 28 miles upstream of the removal site.
  • Maryland: Maryand celebrated the removal of Bloede Dam on the Patapsco River in 2018. Since then, there have been sightings of migratory fish such as striped bass, river herring and white perch upstream of the removal site. Environmental DNA (also known as eDNA) from several other migratory species has been found at the base of Daniels Dam, which is over 6 miles upstream of the removal site.
  • Pennsylvania: Prior to two dam removals in 2015 and 2018 Chiques Creek, in Pennsylvania, was not accessible to fish migrating from the Susquehanna River. Following the removals of Heistand Sawmill Dam and Krady Mill Dam, the watershed now serves as a unique case study in free-flowing conditions and sediment management best practices. Additional work is being done to further increase aquatic connectivity.

To learn more about our progress toward restoring historical fish migration routes by opening an additional 132 miles every two years to fish passage, visit