Chalk · Picardy / Somme–Pas-de-Calais border

Authie

Authie terrain map
Terrain map

The Authie runs quietly along the old border between Picardy and the Pas-de-Calais, from Coigneux down through Auxi-le-Château and Dompierre to the Baie d'Authie where it meets the Channel in a wide tidal mouth.

Species

A proper day on the water

Low and clear — careful approach country. Stay small, stay accurate.

75% confidence in this read
Water temperature for brown trout
Cool — slow
9°C est.ideal 10–16°C
0°14°28°
Why this score · for brown trout
  • Temperature7728% weight
  • Flow6022% weight
  • Clarity9518% weight
  • Feeding Time5013% weight
  • Pressure807% weight
  • Prey Activity3812% weight
Conditions
Level
Dry recently
No gauge reading
Water temp
8.7°C
Estimated
Clarity
Clear
Air temp
10°C
Wind
SW 14 km/h
Gentle breeze
Pressure
1012 hPa
Rain · 48h
0.0 mm
No meaningful rain
Rain · ahead
11.9 mm
Moderate rain · next 48h

Live readings — water temperature is an estimate where the gauge does not record it.

How to fish it · for brown trout
When
Through the open trout season. Iron Blue and CDC grannom in April; olives through May; sedges through summer.
Where
Pool tails and weeded glides through the Pas-de-Calais-Somme chalk stretches. Coastal-margin chalk water; intimate.
Method
Upstream dry to spotted rising fish; long fine leader. The water reads clear — careful approach matters more than fly choice. Move slowly upstream, cast accurately, accept the result.
Kit
9 ft #4 — French karst-stream default. Floating line, 14 ft leader to 4 lb fluoro. Polarising glasses non-negotiable.
Why this works
Good conditions. Clarity is favourable (95), Prey activity is weakest (38).
Through the year
0–3 scale · May highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
1
2
2
2
2
2
2
1
Large Dark OliveHatch
1
2
2
1
March BrownHatch
1
2
1
Iron BlueHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Permits & access
Permit required — see local rules.
  • AAPPMA and private estate water mixed
  • Estate beats around Auxi-le-Château and Nampont-Saint-Martin are well-managed
  • Some fly-only and no-kill parcours.
Directions
Apple MapsGoogle Maps
About this water

The Authie runs quietly along the old border between Picardy and the Pas-de-Calais, from Coigneux down through Auxi-le-Château and Dompierre to the Baie d'Authie where it meets the Channel in a wide tidal mouth. It's the Canche's less-famous sister — same geology, same hatches, less pressure, and a surprising number of genuinely large fish in the lower meadows where the valley broadens. Wild brown trout through the upper reaches, grayling in the steadier pools, and a sea trout run that brings decent fish up from the bay in autumn. The mayfly comes off around the third week of May; the evening sedge hatches through June can be almost absurd. Much of the best water is private estate, but the AAPPMA beats around Auxi are good and unfussy. A river that rewards knowing it.

  • Chalk
Seasons & zones
  • Trout2nd Saturday of March → 3rd Sunday of September
  • Grayling3rd Saturday of May → 31 December

Sea trout: Variable seasonal (2026) — Authie — coastal Pas-de-Calais river between Boulogne and the Somme. Sea trout occasionally taken but not a primary sea-trout destination. Condition-sensitive; presence is localised.

Other water nearby · 5