One of the most significant threats to the American eel is the loss of access to available and historically used habitat. This loss of access translates into delays in the migration of individuals due to anthropogenic modifications to watersheds that no longer ensure the free passage of fish (dams, culverts, etc.).
The partnership between AECOM and AGHAMW was born of an initiative to restore access to important eel habitats in the territory covered by AGHAMW. Restoring access to eel nursery habitat is of paramount importance to First Nations.
Since 2019, several activities have been carried out to restore eel connectivity, as well as a transfer of knowledge to AGHAMW staff to foster their autonomy. These included training in the assessment of obstacle crossings and habitat gain calculations, eel tagging and capture techniques, construction of infrastructure and the operation of eel ladders. In addition, ongoing mentoring is offered to facilitate the analysis and prioritization of obstacles targeted for development.
A total of 13 projects aimed at restoring access to watershed lakes for the eel subpopulation prior to damming have been completed or are underway to open 3,000 hectares of habitat for the species.
The watersheds that have been restored are:
- Dartmouth
- Rimouski
- Cascapédia
- Du Sud
- Mitis
For each site worked on, unique solutions tailored to the requirements of the owners or local players were applied. AECOM is used to working with obstacles of all types and sizes. When the obstacles were dams, the installation of eel ladders was recommended to enable them to be crossed, while for culverts, the development of weirs was put forward.
Of course, restoration and wildlife development work require MELCCFP approval (permits) and the application of standards for work in fish habitat which aims to apply methods designed to protect fish, control erosion and sedimentation (e.g. containment curtains, dry work, etc.), protect riparian buffers, existing structures and sites, and so on.
Fish passage facilities were designed so they don’t affect the structure of the dams, are long-lasting and require little maintenance.
Projects included the following elements:
- Support in the search for funding
- Research, analysis and creation of a priority obstacle matrix
- Carrying out American eel inventories (night observations, electro fishing, ladder traps, fyke nets, etc.)
- Analysis of how dam can be crossed
- Support with SEG permit applications, including those for retention, tagging and fishing
- Applications to the MELCCFP for exemption or wildlife authorization
- Habitat gain calculations
- Negotiations with landowners and/or local stakeholders
- Design of facilities
- Production of engineering plans and specifications for dams
- Production of layout diagrams
- Procurement of materials
- Fabrication of ladders
- Construction of facilities
- Effectiveness and integrity monitoring of facilities
Finally, some sites presented a risk of injury to fish during downstream migration. The AECOM team therefore designed an additional facility to ensure safe passage for fish migrating to spawn. Engineers were able to validate that the stability of the high-capacity dam would be maintained for an increased downstream level following work at the foot of the dam.
