About 36,000 chum salmon eggs incubate in a man-made rocky bed near the community allotment gardens in Oak Bay.
It’s the second consecutive winter volunteers with the Friends of Bowker Creek transplanted hope for future fish into the waterway as part of its salmon recovery project.
The fertilized eggs, donated by Goldstream Hatchery, spend the next couple of months percolating under spawning gravel, that protects the eggs from predators and storm events. By early spring, the juveniles should hatch and wriggle their way through the screen and hastily swim downstream to the Salish Sea.
Salmon travel massive distances, then instinctively return to the stream where they were born. Gerald Harris, chair of the society, holds out hope 50 to 100 adults from this batch of eggs return come fall 2025.
“We are hoping for a very high survival rate for the eggs incubating in the boxes, for the alevins that wiggle out of the boxes and down into the gravel, and for the fry emerging from the gravel and heading downstream to the Salish Sea,” Harris said.
Last year, the group planted roughly 30,000 eggs and saw an estimated survival rate around 70 per cent at that stage. They hope for 90 per cent this year.
“We made improvements to the gravel incubation platform last September that have expanded it and improved flow of water through the gravel,” Harris explained.
However, ocean mortality is high and unpredictable. Volunteers would be thrilled if 0.5 per cent survive and find their way back to Bowker Creek as adults.
“We hope to see our first batch of salmon returning within the next couple of years. In the meantime, there is a lot of work to do, both in the restoration of habitat along the stream and in expanding green stormwater infrastructure throughout the watershed to improve water quality and moderate flows,” he said.
The first batch of 30,000 chum salmon eggs planted in January 2022 hatched without a hitch.
In mid-March that year, Val Aloian, tasked with checking the water temperature and levels every day, predicted the eggs nestled into a rock bed would emerge about April 1. She spotted the small fry swimming about March 30.
If all went according to plan, the fry followed the current down to the Salish Sea with some anticipated to return in November 2024.
Some questions remain, such as the drop from the culvert to the creek at Beach Drive, where Bowker Creek reaches the Salish Sea.
“It looks high for chum salmon to get up. We think they will make it, but will need to see what happens,” Harris said. A consultant biologist told the group the flow pattern at higher flows is not a simple drop, and probably offers the chum a way up.
A species of sculpin found upstream from the Beach Drive culvert also requires easy passage from the ocean, so they figure if the sculpin can make it, chum salmon can make it.
Fisheries and Oceans Canada, which provided the required approval for both egg projects, also thinks the adults will be able to get back upstream to the egg incubation site, Harris said.
He notes that upstream from where the eggs incubate, there is no way for chum to pass upstream through a long culvert that runs under Firefighters’ Park.
“We look forward someday to daylighting Bowker Creek though Firefighters’ Park, but that is a big project a few years in the future.”