The Aysén carries the combined flow of the region's rivers down to the fjord at Puerto Chacabuco, and it fishes like the big water it is — glacial-alluvial, powerful, and best covered from a boat rather than waded. Brown and rainbow trout hold in softer margins and back eddies out of the main push, while chinook salmon add real size and weight to the mix lower in the system. Streamers and sculpin patterns fished with authority, not finesse, are the order of the day, with dry-dropper rigs working the calmer side channels. It's less a wading river than a floating one, and a guide who knows the current channel configuration makes the difference between a good day and a frustrating one.

• Glacial