Aquatic Barriers & Fish Movement

Fish and other aquatic organisms need to be able to navigate to habitats upstream and downstream in order to be able to spawn, feed, and ultimately survive.

salmon attempts to leap over the dam in Etienne Brule Park

Applied Research on
Aquatic Barriers and Fish Movement

The loss and fragmentation of habitat in urbanized areas like the Greater Toronto Area inhibits aquatic species from completing critical life cycles, such as summer feeding, overwintering, and spawning.

For example, instream barriers such as dams, weirs, and road crossings impede the movement of fish and other aquatic organisms. There remain many remnant barriers throughout the Toronto region.

It is imperative to prioritize opportunities to benefit aquatic ecosystem health through barrier removal.

Applied research on aquatic barriers and fish movement guides strategic restoration and planning activities through:

  • Mapping and assessing aquatic barriers to identify connectivity issues
  • Developing and updating the barrier removal prioritization tool
  • Incorporating habitat quality metrics into barrier removal decisions
  • Assessing the seasonal habitat needs and movements of fish

A “notch” in the centre of the Old Mill Dam on the Humber River is designed to aid salmon in their migration upstream.


TRCA Watershed Planning and Ecosystem Science: