The Nushagak is one of the great salmon rivers of the planet — a vast, brown, lowland river running down to Bristol Bay that hosts king runs measured in the hundreds of thousands, and where the kings go, the rainbows and the Dolly Varden feed. It's big, pushy, tea-stained water, fished mostly from boats out of lodges and tent camps, and it fishes in seasons: kings through the early summer (a run to respect, not a fly-rod trophy to chase casually), then the rainbows and char keying on smolt and, by autumn, on eggs and flesh. It is genuinely one of the few Bristol Bay rivers with a live USGS gauge, which helps read its moods, but the scale is the thing — this is a system you read at the river level, not the pool. Plan around the runs, mind the bears, and check the orders before you go.

• Mixed