Why are there closed seasons for trout, and why do they differ by species?

Closed seasons exist because spawning trout are concentrated, aggressive, and absurdly easy to catch — a season's worth of breeding adults packed into a few pools or one shoal, defending against anything thrown at them — and because angler traffic destroys redds even without a hook in the water. The dates track each species' clock, which is why they differ: brook and lake trout waters typically close in late September or early October ahead of the fall spawn and reopen in winter or spring, while rainbow closures protect April–May and often extend far enough to shield eggs still in the gravel. In Ontario these rules are set per Fisheries Management Zone and change at zone boundaries; everywhere, the closure calendar is per-water law, not folklore — read the current regulations before the trip, not after.

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