This week, we are starting the construction of a second breach in the North Arm jetty. This is part of a five-year restoration project that we began in 2019, which saw us construct three breaches in the Steveston Jetty and another in the North Arm jetty.
The goal of these breaches is to restore natural migration routes for juvenile salmon and other fish. Opening the jetty will also restore the natural flow of freshwater, fine sediments, and processes that create a link between the river and the estuary. This project is part of long-term vision to support the recovery of the Fraser River, the estuary, and its salmon populations.
The problem created by jetties
Jetties in the Fraser River estuary, and the accompanying dredging of the river, began in the early 1900s to aid boats and ships into the arms of the Fraser River. Jetties interrupt the natural movement of juvenile salmon and other fish by forcing them from the freshwater river into the deeper waters of the Strait of Georgia before they are ready. Jetties block their access to the brackish marsh and sandflat habitats young salmon want to reach while they feed, grow, and make the transition from freshwater to ocean water. The North Arm jetty was constructed in 1916. It created a 6.8 km long barrier that has altered the connection between the North Arm of the Fraser River and the estuary, since it was constructed.
Plans for the North Arm jetty
From November to December, 2023, we aim to construct a second 30-meter-wide breach in the North Arm jetty. We will continue to monitor the breaches to assess their effectiveness in creating access for salmon, and for their contribution to creating a more natural estuary that flows more like it did prior to European arrival and construction of jetties .
In 2022, the first 30-meter-wide breach in the North Arm jetty was constructed. In follow up monitoring, all five species of juvenile salmon were found using the breaches. At high tides, over 700 juvenile chum were moving through the breach every hour, and over 100 juvenile Chinook per hour. We also conducted baseline fish surveys across the lower river and estuary between 2018 and 2023. During this time, high densities of juvenile salmon, particularly juvenile Chinook salmon, were found in the North Arm, demonstrating that the habitat in the North Arm is still important to salmon.
Raincoast believes this second breach in the North Arm jetty will not only improve passage for juvenile salmon, it will also help improve habitat in the estuary particularly for Chinook, chum, and sockeye. It will also help to recover the estuary ecosystem by restoring ecological processes through the movement of freshwater, fine sediments, and nutrients that are currently stopped by the North Arm jetty.
Thank you to our project partners, Ducks Unlimited Canada, Lower Fraser Fisheries Alliance, and Tsawwassen First Nation. Thank you to Musqueam Indian Band, Metro Vancouver and the Vancouver Fraser Port Authority for their support.
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