Cooling Merrimack tributaries set up fall smallmouth and brown trout

What's biting

What's next

Expect these readings to keep drifting downward if nights stay cold. Flows are low and stable, so tributary runs should stay clear and fish will be spooky. Plan the best fishing for the warmest part of the afternoon, when a degree or two of warming can nudge smallmouth into feeding. Early mornings at these temperatures are typically slower.

For smallmouth, work slowly. Paddle tails on an underspin or a bladed swimbait, per Tactical Bassin, are a sound way to cover water while still getting a reaction. Per Fishing the Midwest, walleye in cooling water respond to a plain rig, a bottom bouncer weight with a snell and nightcrawler, fished along structure where baitfish concentrate. Lighter flow means longer leaders and quiet approaches in the rivers.

The First Quarter moon sets in the evening, so late afternoon into dusk is a reasonable window to plan around. Check local conditions and state regulations before targeting trout, as fall rules on many waters differ from summer rules.

Context

Mid-October is typically the transition period for New Hampshire freshwater. Surface water on larger lakes is cooling toward turnover, and Field & Stream advises beating turnover by moving to clear, shallow bays or creek arms that have not yet mixed, covering water with search baits to find active fish. Fall turnover rarely hits a whole lake at once, so clean water is the most direct path to bites. Tributary temperatures in the 40s are normal for the third week of October and put this season on schedule. The coming weeks usually bring slower, deeper smallmouth patterns and the tail end of the fall trout movement before ice-in.