Monitoring an active restoration project… in a pandemic

With all of the struggles around accomplishing a field season, we were incredibly happy to see the high rates of juvenile salmon passage that occurred.

Dave Scott holding viewfinder with salmon smolt

Photo by Alex Harris / Raincoast Conservation Foundation.

Just as we were getting excited about starting our field season to monitor the effectiveness of Raincoast’s Fraser Estuary Connectivity Project, conditions with the pandemic began to get serious and we realized our plans had to change. We are right in the middle of our exciting initiative to breach the Steveston jetty, following phase two construction last November, and losing a field season would really set back our ability to understand the effectiveness of our project. Our main goal is to monitor juvenile salmon passage through our breaches and the vast majority of the outmigration happens in April and May, so even a few months delay would essentially mean a total loss of important data. 

Our project takes place in the Lower Mainland where myself and our field crew live, so we don’t have to travel. Fortunately, our jetty breaches are located just across from Steveston, where we can meet and maintain physical distancing while setting our fyke nets across our jetty breaches to monitor juvenile salmon passage.

Our monitoring setup is simple; we have a net with two wings which connect to a trap box with a small circular opening which fish are funnelled through into a bag in the back where they can be retrieved safely. When the tide is at the right level, we set our net across the channels which are developing at our breach locations, and a strong current of water moves from the river through the breaches onto the banks, allowing the passage of juvenile salmon into our nets. 

In 2019 we captured 454 juvenile salmon moving through our breaches across our sampling season, with the greatest catches coming in April and early May. We only captured small juvenile salmon fry, including a total of 300 juvenile chum, 152 juvenile chinook and 2 juvenile sockeye over 13 sampling occasions.

In 2020 we knew that the potential for juvenile salmon passage for this year was high. Last fall a large number of pink salmon returned to spawn, along with above average numbers of South Thompson ocean type Chinook, and large numbers of sockeye in 2018, which mostly hang around in a nursery lake for a year before migrating to the ocean in their second spring as smolts.

Just as we had hoped, our catches at the breach locations increased this year with 1,480 total salmon, including 297 Chinook, 174 sockeye, 420 pink, 20 coho, 569 chum. We even had a few days when we captured all five species of salmon in one set! We captured both ocean-type and stream-type Chinook, and large bursts of pink and sockeye, and captured ocean type Chinook  at breach locations in every month from March through August. 

With all of the struggles around  accomplishing a field season, we were incredibly happy to see the high rates of juvenile salmon passage that occurred. For Chinook, our main target species, we saw higher rates of passage; last year we only captured them from March into May, whereas this year we saw consistent passage as late as mid-August, which was especially inspiring. The breaches have also continued to result in channel formation over time with the passage of water, creating further opportunities for salmon passage with each successive tidal cycle slowly eroding a natural pathway, which had been blocked for over 100 years! 

Now, we are turning our sights on some of the other major barriers in the estuary like the North Arm jetty, while also continuing our monitoring here next season.

Before and after the breaches were made in the Steveston Jetty.
Raincoast biologist Dave Scott in hardhat during jetty decommision

Dave Scott, Research and Restoration Coordinator for the Lower Fraser Salmon Program

Raincoast biologist David Scott is focussed on understanding juvenile salmon life histories in the Fraser Estuary to facilitate habitat restoration, salmon recovery and better management. Dave is also a PhD student in the Pacific Salmon Ecology and Conservation Laboratory at the University of British Columbia where he studies under highly renowned salmon researcher Dr. Scott Hinch.