The science behind monitoring at the Big Bar landslide response in British Columbia
Between June and the end of the migration season in November, two types of fish monitoring methods are used below and above the Big Bar landslide site – hydroacoustic sonars and active radio tagging. As part of the Big Bar response, monitoring provides us with the key to understanding fish population size, movement and health in near real time. This data is then used to calculate the migration time of individual fish of select species, their size and gender.
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Transcript
So, monitoring efforts are important, they let us understand immediately if our interventions are having a positive or negative effect.
Be it blasting, rock manipulation, transport and the construction of the "nature-like" fishway
have allowed salmon to start passing through the slide area.
In order to monitor salmon for the Big Bar landslide response we're using two main techniques.
We're using the radio tag program where we apply radio tags to different salmon across all species, and that'll allow us to track what they're doing in real time.
The fish swim past a network of receivers, up to the slide area, and then up through the spawning areas as well.
So we can understand how fish are migrating up to, through, and beyond the slide.
Pair that with some hydro acoustic sites, some sonar sites that allows us to see salmon entering the slide area and exiting the slide area.
Monitoring can help with enhancement efforts in a couple of ways.
First, it allows us to understand which populations suffered the most from the slide or are in the most need of emergency enhancement.
Second by getting real time DNA information we're able to understand what populations were approaching the slide area or held up, which allowed us to plan which ones we could target for enhancement in 2020.
And then DFO’s larger monitoring program was able to help us with our terminal collection.
We have a core group of staff, and we're working directly with a whole host of different groups all over the watershed.
Groups like the UFFCA, Upper Fraser Fisheries Conservation Alliance, helping us with monitoring some upstream stations.
We’re also sharing sonar information from our programs.
They’ll share their sonar counts with us and we can compare them to what we’ve seen pass through the slide.
Comparing 2019 to 2020, based on our preliminary monitoring results, we're seeing a higher success rate of salmon through the slide area.
Salmon were able to pass through earlier in the season and should be experiencing lower mortality rates as a result.
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