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Water Boatman (Corixidae)

Other, hatching September–November, active in water between 45 and 65°F, and imitated at #14–18. Recorded from the Wisconsin driftless and northern Wisconsin, where 1611 Wisconsin rivers on this site carry a page.

Water Boatman, Corixidae
Corixidae-heteroptera — Halvard : from Norway., CC BY-SA 3.0, via Wikimedia Commons.
Subbasins with trout water where it is on record: 37 of Wisconsin's 43.
See Wisconsin's trout water on the live map → Every reach coloured by water temperature — the water these hatches come off.

What it is

Other · Corixidae · adult

A small, oval, hard-backed bug with long fringed rear legs held out like oars, and a silvery bubble of trapped air carried under the body when it dives.

An air-breathing beetle-like bug that swims down to the bottom carrying a silver bubble and rows back up for air. Autumn flights land them on the water in numbers, and the take is on the rise back to the surface, so a rising retrieve beats a dead drift.

When it hatches

Peak is September–November. The pale months either side are the shoulder — the app widens a peak by one month in each direction and recommends the bug there, and no further: that widening is bounded so that a bug peaking in May is never offered in August.

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peak shoulder not recommended

Water conditions

The band is a water temperature, not an air temperature, and it is the range in which this insect is worth fishing — for a mayfly that is the emergence window; for a scud or a midge it is simply the range trout will still eat one in.

45°F 65°F

Active from 45°F to 65°F. On this map that is cold, cold-transitional, cool water — the band crosses 2 of the three breaks the river colours use. Breaks at 58, 64 and 70°F.

Stages

What the insect is doing, and what that means for what you tie on.

StageWhat it is
adult Swims down to feed and must return to the surface for air, so the natural is constantly rising. Autumn flights land them on the water in numbers. Fish it with a lifting retrieve — the take is almost always on the way up.

Matching flies

4 patterns in this book imitate the Water Boatman, across its stages. Which one to tie on follows the stage the water temperature says it is in — the app makes that call on a live reading; this page lists the whole set.

Where to find it right now

The rivers with a page here that sit in this insect's regions, with a USGS gauge reporting water temperature. This list is re-ranked against the reading each gauge is sending now and today's date, so it is live — the fallback below it, if the readings do not arrive, is each river's measured July mean.

Regional presence

Regions, not collection records. This insect is recorded from the coarse regions below; nobody has surveyed which named river it has been caught on, and this page will not pretend otherwise.

Rivers in these regions with a page here

Related hatches

Same family, or overlapping this one's calendar on the same water.

Open the trout map →Every trout stream near you, coloured by today's water temperature.