The offshore fleet that sees Bristol Bay's salmon run coming

About 200 miles southwest of Bristol Bay, out in the open water off Port Moller, a couple of research vessels have spent the past month doing something remarkable: catching a glimpse of the world's largest sockeye run before it arrives. This week they sent up one of the season's final signals.

The Port Moller Test Fishery is an early-warning system, running since 1967. Because sockeye take roughly six to nine days to travel from those offshore waters to Bristol Bay's rivers, the boats — sampling fish daily along a line of stations stretching up to 85 miles out — effectively see the run about a week before it hits the fishing districts. Scientists even run genetic tests on the catch to estimate which rivers the fish are bound for, giving fishermen, processors, and managers a preview of how big the run will be, when it'll peak, and where to be. It's the first real check on the preseason forecast, which this year predicted a Bristol Bay sockeye run of about 44 million fish, with roughly 32 million available to catch.

Now that window is closing. The test fishery wraps around July 15, meaning this week's advisory is one of the last offshore reads before the season plays out entirely on the numbers coming in at the rivers themselves.