The Big Bar landslide, first identified in June 2019, resulted in an unprecedented response by provincial, federal and First Nations governments due to the threat the slide posed to Fraser River salmon runs. Now, as the second year of response comes to a close, and with over $50 million spent, what have these efforts achieved, and what actions are governments taking next to support wild Fraser River salmon affected by the slide?
Though the landslide at Big Bar occurred late in 2018, it was months before it was noticed. By the time it was discovered, 2019 Early Stuart and Bowron Lake sockeye and spring Chinook runs were decimated as the adult salmon could not get past the slide. Once identified, the response team worked quickly, despite tricky site conditions that initially limited access to the site for crews. Through September 2019, efforts to get salmon past the slide included trapping and trucking fish to a location above the slide, and attempts to alter the slide site to improve natural fish passage.
In early 2020, efforts to improve fish passage kicked into high gear with crews working, sometimes around the clock, to improve access to the remote site and increase safety for crews working in the steep canyon, where the risk of further rock slides is high. Blasting was performed to improve passage for salmon through the slide site and despite increasing complications due to COVID-19, planned blast work was completed in early spring. However, despite the blasting, high flows from this year’s large snowpack resulted in fast, turbulent water, making migration difficult for salmon overall, likely impacting how many fish were able to return to their spawning grounds.
To facilitate collection of salmon for truck and transfer, crews completed the construction of a fish ladder in May, and local First Nations deployed a fish wheel in June. The fish wheel also helped to facilitate tagging of salmon to monitor their movement from the Fraser River into their natal streams. Crews onsite also installed a Whoosh system- nicknamed the salmon cannon- a set of six tubes used to transport salmon. All these transportation methods were used to transport salmon above the slide site while river flows were high. By mid summer, river flows reduced, making it easier for salmon to migrate past the slide site unassisted and as of October, over 161,000 salmon were observed upstream of Big Bar. Out of those, roughly 1,500 salmon were transported above the slide using the trap and truck method and 8,000 using the Whoosh system. Of these, over 1,000 salmon were tagged.
DFO and First Nations crews also released 20,000 Early Stuart sockeye fry into Gluske and Hudson Bay Creeks in early October. These fry were raised from eggs produced by adults captured downstream of the Big Bar site in 2019. Those eggs were collected as an emergency measure to protect the already at-risk run. This year, these emergency measures continued, with 360 Early Stuart and 44 Bowron sockeye captured for collection of eggs and milt. Of the eggs collected, about half have developed into embryos, 125,000 and 10,000, respectively.
In mid-November 2020, threatened Interior Fraser coho salmon are wrapping up their migration past the slide site, which they were able to do without assistance due to moderate river flows. With salmon migration ending for the year, crews are working to remove equipment and winterize what needs to stay at the slide site. The time between now and when work will resume in the new year will be used to assess this season’s approaches, to determine what were the most effective methods for facilitating salmon passage. With a recently announced La Nina weather system predicted to result in a high snow pack, next year may also feature a prolonged period of unfavourable river flows for migrating salmon, and may complicate next year’s work to improve fish passage.
We will have to wait to see how the Fraser River salmon runs upstream of the landslide respond to the emergency measures that have been taken. Preliminary reports of salmon escapements will become available in the coming weeks and months.
The response to the Big Bar slide was impressive in scale and led to unprecedented coordination between First Nations, provincial, and federal governments and other community partners. Numerous approaches and innovative solutions were employed to increase fish passage past the slide site and we commend the efforts taken so far.
However, regardless of how effective the response to this crisis will be, Fraser River salmon runs still face a wide range of threats. Most Fraser runs have been in a state of decline with 12 of 13 Fraser Chinook populations at risk or threatened and this year marked the lowest return of Fraser River sockeye on record. Imagine if the year to year declines of wild Fraser River salmon were addressed with as much urgency, innovation and funding as the Big Bar landslide was? The situation would be much less dire.
Work will continue next year to improve migration at the Big Bar site and we will continue to monitor the response and provide you with updates.