By Noah Korver, Local Journalism Initiative Reporter, Yukon News
Staff from the Whitehorse Rapids Fish Hatchery together with partners at the Department of Fisheries and Oceans (DFO), and Kwanlin Dün First Nation (KDFN), conducted their annual release of salmon fry into Yukon River tributaries Tuesday, slinging tens of thousands of fish by helicopter into remote spawning beds in Michie Creek.
This work is funded by Yukon Energy which owns the hatchery facility and is operated at based on direction from the DFO.
Travis Ritchie is the director of Risk and Compliance at Yukon Energy and says the project has been ongoing for over 40 years with the goal of offsetting the number of fish killed when juvenile salmon transit through the dam on their way from upstream spawning beds to the Pacific Ocean.
“Roughly 30 per cent of fish that pass through the [dam] facility don’t make it,” says Ritchie explaining how some fish headed downstream become fatally entrained in the facility’s turbines. “The hatchery is intended to directly mitigate that by putting fish back in the river”.
Ritchie explains how every year the DFO uses data on how many adult salmon are returning upstream and which spawning beds they are returning to in order to direct the hatchery on the number of fish to breed and where they should be released.
The yearly breeding process begins in the summer when hatchery staff begin the process of collecting mature fish, known as broodstock, for breeding. The practice of raising and releasing hatchery fish has sometimes been criticized for producing genetically weaker fish and diluting wild salmon genetics. To help mitigate these issues, Ritchie says the hatchery team practices “matrix spawning”.
In simple terms, matrix spawning involves taking eggs from a female salmon and fertilizing them with sperm-bearing milt from several different male salmon to help create a wider variety of genetic makeup among each generation of salmon raised at the hatchery.
“We’ll [also] take a percentage of hatchery fish and wild fish as broodstock and they breed those in such a way that it helps distribute the wild fish genes as much as possible,” says Ritchie.
Once the fish have been bred and raised into the baby salmon (called fry) they are ready to be transported to their native spawning beds. Located in smaller tributary creeks and streams branching out from the Yukon River, these gravel-bottomed shallows acts as salmon nurseries. The loose gravel stream bottoms allow the female salmon dig down and lay their eggs in protected nests, while the oxygen-rich fresh water helps promote embryo development in the eggs. Once the salmon hatch and develop into tiny fry they will spend anywhere from a few months to a whole year in their natal streams before migrating thousands of kilometres down the Yukon River to the Pacific Ocean.
It is during this stage that the salmon imprint the unique smell of their natal stream into their brains. It is by following this unique smell that the salmon are able to find their spawning beds again in several years when they return from the ocean to spawn at the end of their life cycle. Releasing the hatchery raised salmon into these natal streams as fry allows the fish to also imprint this smell, ensuring they are able to return to these spawning beds alongside wild salmon as adults.
Tuesday’s fry release saw over 60,000 salmon fry set free into spawning beds in Michie Creek. Given the remote nature of these areas the hatchery staff utilized specialized helicopter buckets to transport and release fish. Staff filled the buckets at the hatchery facility just off Millennium Trail in Whitehorse’s Riverdale neighbourhood before attaching them to a sling underneath a helicopter. The fish were then flown to Michie Creek where the buckets were set in the water. A unique cable system on the buckets ensures they can tip over and gently release the fish into the stream once they are down. The system also features an aerator and oxygen bottle attached to the buckets to ensure the fish are given a healthy supply of oxygen during their flight.
Moving forward Yukon Energy is working to explore alternative ways to manage salmon around its hydro facility. Ritchie says the agency hopes that new technologies and changes to current policy are being explored with input from partner agencies and local First Nations with the hope of reducing or even eliminating the need for hatchery fish to maintain healthy salmon stocks.
According to Ritchie, Yukon Energy recognizes that a hatchery is “not the perfect way” to manage the negative effects of the hydro facility. “If we could avoid [killing fish] completely, that would be great and that is what I think our partners have challenged us to do.”
Yukon Energy’s partnerships also extend beyond just mitigation of the dam and hydro-power facility. The team at the fish hatchery also partners with a variety of government and First Nations organizations to help gather data on salmon returns and wild egg numbers to help inform the number of fish the hatchery will raise in any given year.
Another way the hatchery contributes significantly to salmon conservation is through the collection of tissue samples for scientific research. When the team collects wild and returning hatchery salmon for broodstock they also gather tissue samples from the fish with data and sample material sent to various institutions across Canada and the United States.
“Here is a great place to collect samples because it’s a direct place where you’re taking fish out of the river,” says YukonEnergy’s director of partnerships, Tom Buzzle.
“We share samples of all sorts of tissues from the fish related to biological surveillance and resource management programs in Alaska.”
Alongside exploring new policy and technology to mitigate the dam’s effects, Buzzle says Yukon Energy is also working to deepen the involvement of its First Nation partners.
Buzzle says the organization hopes to pass off management of the fish hatchery as well as the fish ladder at the Whitehorse Hydro Facility to the Kwanlin Dün and Trʼondëk Hwëchʼin First Nations within the next several years. “We’ve created agreements that they will eventually jointly take over these facilities. So [the fish ladder] will still be open to public… but it will also be a cultural place”.
