Forecasting Fish

BC Steelhead and the Tyee Test Fishery

IT STARTS AROUND THE SAME TIME every year, in late June or early July. And on a day that you should be fishing, you're instead making furtive mouse clicks and talking in hushed tones with your buddies, always reminding yourselves that it's still too early to say anything definitive. Then, as trout fishing ebbs into its August doldrums, you start acting more like a day trader than a fisherman, poring over graphs and projecting trends like you're an extra in The Big Short.

This is all because of the Tyee Test Fishery, a program used since 1955 by Fisheries and Oceans Canada (AKA Department of Fisheries and Oceans, or DFO) to "evaluate the magnitude" of Skeena River salmon and steelhead returns. Like their fellow migratory-fish lovers in the Pacific Northwest, who spend summers watching daily fish-ladder counts up the Columbia River, B.C. steelheaders look to the Tyee Test Fishery.

The operation takes place at Tyee, just upstream of the Area 4 commercial sockeye fishery on the Skeena. Starting around June 10, a DFO contractor begins laying gillnets in order to get an idea of how the year's run is shaping up. Along with commercial numbers, the test fishery provides an estimate of the year's sockeye run, while also collecting data on the other salmonids: coho, chinook, pink, chum and, of course, steelhead. This data is then made public.

"Simplistically and generally you could say higher Tyee steelhead numbers should mean better overall fishing," says Keith Douglas, chair of the North Coast Steelhead Alliance in Smithers. "But, as we know, steelheading isn't so simplistic. The split of where the fish go can vary year to year, and if you're on a smaller Skeena trib, larger overall numbers may not translate into a better fishing for your particular system."

The gillnets—200 fathoms long and 20 feet deep—are lowered 2 to 4 times a day, according to tide depth and river flows, for an hour at a time. Hourly catches are recorded and then averaged to get a daily index. A multiplier is then used to estimate total escapement. For species other than sockeye, the multiplier is less about rigorous math than educated estimates—more than 90 percent of the Skeena's sockeye can physically be counted as they pass the Babine River weir.

Though steelhead numbers aren't as definitive, DFO fisheries biologist Mark Beere says the index for steelhead can still provide valuable data. "It's a sockeye test-fishery first, and some argue that all it can really tell us about steelhead is whether it has been a bad year or an exceptional one," Beere says. "But I would say it does more for us than that."

When Douglas looks at numbers from Tyee, he's most concerned about the early portion of the run. "I guide and fish on a system with early returns, but it's also because early returning fish are our most important. They come the earliest and stay the longest, thus providing the most access to fishermen and the fishery. And they've been disproportionately impacted by commercial fishing over the decades."

The number of returning steelhead on the Skeena has averaged around 25,000 since the mid 1950s, but as much as 40 percent of some stocks die every year as bycatch in commercial sockeye nets. Nevertheless, Douglas agrees with Beere that, despite its shortcomings, the Tyee Test Fishery still provides meaningful insights.

One can imagine that in years such as this—the fourth strongest steelhead return on record—these graphs are being taken seriously. And from where I sit in camp on the Skeena, I can tell you for certain: it's looking damn good.