New Pacific salmon research is encouraging anglers to rethink the way they practise catch-and-release

TACKLING MORTALITY

Scott Hinch, the head of the Pacific Salmon Ecology and Conservation Laboratory at the UBC, led the research. For the last 20 years he and his grad students and collaborators have studied many aspects of salmon survival in commercial, Indigenous and freshwater recreational fisheries. But it wasn’t until the creation of the B.C. Salmon Restoration and Innovation Fund that he had the financial backing to look into what he calls the elephant in the room: recreational salmon angling in the marine environment.

Starting in 2019, his lab conducted 15 unique studies related to catch-and-release mortality in three areas around Vancouver Island: the Discovery Islands near Campbell River; the Strait of Juan de Fuca near Sooke; and Barkley Sound near Bamfield. Mostly, it sounded like a dream job. Hinch’s team went fishing, catching more than 1,500 coho and chinook salmon in total, and experimented with various fishing techniques, gear and handling practices. For example, they used different hook sizes, fished with and without a net, and varied the length of time the fish were out of the water.

With each catch, they recorded data on the fish’s condition, scale loss, hook injuries and fin damage. They also scanned the fish for fat content—an indication of health and maturity—and took slime, blood and tissue samples to further determine the health of the fish and record their DNA, which also revealed their natal streams.

The focus of the new research was to observe the salmon in the weeks and months following their release

What makes the findings noteworthy is what the researchers did after they caught the fish. Historically, catch-and-release studies involved catching fish, putting them in a land tank and observing their survival over, at most, three days. “One thing we’ve learned over 15 to 20 years of research is that a lot goes on after day three,” Hinch says. So, the focus of the new research was to observe the salmon in the weeks and months following their release.

For that, Hinch’s researchers attached telemetry tags to the fish, allowing them to keep track of their locations via the constellation of acoustic listening stations around Vancouver Island. “We could really light up the underwater environment and track migration rates in the most benign way possible,” Hinch says. Any fish that didn’t reach its spawning stream, they surmised, probably died along the way.

In Barkley Sound, the team also worked to better understand how salmon might perish after release. Instead of releasing every fish, they transported some specimens to the Bamfield Marine Sciences Centre, where they were held in land-based tanks for up to two weeks. Necropsies were then performed to study the long-term impacts of any injuries sustained, and the role of pathogens.

By combining all their research, Hinch says his team created one of the most thorough catch-and-release studies ever conducted. “We went from one end to the other in terms of invasiveness of what fish can expect from anglers,” he says. “When you combine all the studies, it develops a wholesome picture of what happens to fish depending on how they are handled.”

The takeaway, Hinch concludes, is that small and easy changes can result in much better outcomes for chinook and coho salmon.