Salmonids

Salmonids cope badly with warm water. Past a certain threshold they stop feeding and retreat to spring-fed reaches, cool confluences and the deep layers of lakes. That constraint explains their distribution — headwaters, mountain lakes, upland rivers, the cold water of the north — far better than any map of borders.

They are also the most wary fish in the catalog. In clear water they spot a cast shadow, a heavy footfall on the bank or a leader that is too thick. You fish upstream, under cover, with fine lines — this is the discipline where the approach matters more than the bait.

Many are migratory, wholly or in part. Long runs to the spawning gravels concentrate fish at precise times of year and leave them particularly vulnerable then: that is why their waters are, almost everywhere, the most closely regulated.