Sockeye Salmon in the Alouette Watershed

Since 2008, the Alouette River Management Society and the Fraser Regional Correctional Centre have administered the Alouette Sockeye Adult Enumeration Monitoring Program under BC Hydro’s Alouette Water Use Plan (AWUP).  The plan included a seven year monitoring component trapping, enumerating, and obtaining tissue samples from returning adult sockeye salmon (Oncorhynchus nerka).

In order to assess the feasibility of anadromous sockeye salmon re-introduction into the Alouette Reservoir, studies are being conducted to determine the return success of sockeye adults to the Allco Fish Fence. 2020 was the fourteenth year of studying Alouette adult sockeye salmon enumeration. Originally, through BC Hydro’s Water Use Plan for the Alouette Watershed, a spring surface release from the Alouette Dam allowed for kokanee/sockeye smolts to migrate to the ocean from 2007 to 2020. The first surface releases occurred in 2005 and in 2007 the first adult sockeye returned to the Alouette Watershed.

Figure 1. First Sockeye returns in 80 years, 2007.

Purpose of Monitoring Program

The main purpose of the original seven-year Alouette Adult Sockeye Enumeration monitoring program as funded under BC Hydro’s Alouette Water Use Plan was to establish whether out-migrating Alouette Lake Reservoir kokanee/sockeye smolts were capable of adapting to an anadromous existence. Adaptation is considered successful when sockeye return from the ocean environment to spawn in Alouette Lake. Additionally, the original monitoring program sought to establish the timing and genetic structure of the returning sockeye run and to assess whether ocean survival rates of returning re-anadromized kokanee were comparable to that of sockeye stocks found elsewhere.

Sockeye salmon were extirpated from the Alouette River by dam and tunnel construction in the 1920’s. Since 2005, an experimental spill from the Alouette Dam has resulted in “sea run kokanee” smolts and returning adults.  These adults are seen as a conservation priority in the Salmonid Action Plan section of the Watershed Plan for the Alouette Watershed.

Sampling & Monitoring Process

Since 2008, the Alouette River Management Society (ARMS) has captured sea-run kokanee below the Alouette Dam at the Allco fish fence, sampled their DNA and transferred them to the Alouette Reservoir by truck and trailer.  Parental analysis, by the Department of Fisheries and Oceans Pacific Biological Station in Nanaimo, was used to identify the off-spring of these sea-run kokanee in samples of smolts and lake-resident juveniles, in order to evaluate the overall reproductive success of the transferred adults.

Tissue samples are also collected from all sockeye in order to ensure that returning adults were Alouette stock and not strays from other nearby coastal systems. The viability and authenticity of kokanee smolt “re-anadromization” is dependent on the stocks ability to adapt to salt water conditions, to adopt behavioural strategies to compete and avoid predation in an ocean environment, and to recognize and return to their native lake/stream system to spawn. Through the Alouette Adult Sockeye Enumeration program, sockeye returning to the Alouette River are collected, counted, aged, genetically tested and released into Alouette Lake.

Figure 2. ARMS staff Greta and Sophie sampling a Sockeye that has returned
Figure 3. A returned sockeye being measured and photographed

This information and the work of the Alouette River Sockeye Reanadromization Project committee, is building towards a business case to present to BC Hydro’s Board of Directors to get fish passage over the dam for sockeye salmon and other species that have been excluded from their traditional spawning grounds in the upper Alouette Watershed since 1929.  Sockeye salmon were extirpated from the Alouette system for close to eighty years when in 2005, with an accidental release of water through the Alouette spillway, some resident kokanee swam out and two years later came back as sockeye salmon.

The Allco Fish Hatchery is located approximately 5.5 kilometres (km) south of the Alouette Dam and associated reservoir (otherwise known as Alouette Lake) in Maple Ridge, British Columbia and has operated since 1979 under the direction of BC Corrections with authorization and guidance from the Department of Fisheries and Oceans.

Figure 4. South Alouette Fish Trap and Fence
Figure 5. South Alouette Fish Fence at Allco Fish Hatchery
Figure 6. Sockeye Salmon Transportation Trailer

The adult Sockeye enumeration program is part of a larger body of work, the “Alouette Watershed Sockeye-Fish Passage Feasibility Project” which is funded by the Fish and Wildlife Compensation Program (FWCP).  The FWCP is a partnership between BC Hydro, the Province of B.C., Fisheries and Oceans Canada, First Nations, and public stakeholders to conserve and enhance fish and wildlife in watersheds impacted by BC Hydro dams.

The Alouette River Sockeye Restoration Program is a partnership between ARMS, BC Hydro, Fisheries and Oceans Canada, local First Nations including Katzie First Nation, Ministry of Environment, and LGL ltd. The Alouette River Management Society gratefully acknowledges the financial support of the Fish and Wildlife Compensation Program for its contribution to the “Alouette Watershed Sockeye-Fish Passage Feasibility-Year 4” project.