When does the Large Brook Dun hatch?

April–June, typically 12:00–19:00. It starts from about 8°C, peaks around 12°C and tails off by 17°C.

What flies imitate the Large Brook Dun?

March Brown, Greenwell's Glory, Pheasant Tail Spinner, typically on a #12–10 hook.

Spinner stage: 10–13mm. That matches a #12–10 hook.

Mayfly · Aquatic insect

Ecdyonurus torrentis

Size

10–13mm

Hook size

#12–10

Hatch window

Season April–JunePeak time 12:00–19:00

Water temperature

12° peak

8°17°

How fish feed on it

An evening return over broken water. Thin, and rarely worth waiting out in early-spring cold.

Flies that imitate this

March Brown

Greenwell's Glory

Pheasant Tail Spinner

Ecology

Rivers & stillwaterAlpine riversSpate rivers

Where you'll find this

Present throughout