Stoneflies
Gammarids
- Ecology: Good
- Chemical: Unknown
WFD classification · FRAR05
Rules at a glance
- Day tickets
- Fly only
Water temperature for Grayling
Ideal11°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Autumn through November prime.
Where
Faster runs in the middle and lower stretches.
Method
Euro-nymphing through the deeper pockets is the daily default; switch to dries on autumn afternoons when sedges and small olives come off. Long fine tippet for the clear water.
Kit
10 ft #3 nymphing rod for the deep pockets; 9 ft #4 for dries. 4 to 5 lb fluoro tippet, 12 ft leader.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Hatch timeline · tomorrowPeak at 18:00
12:00(now) — Autumn Olive
Stage: On emergersApproach: Emerger or dryActivity: 29%
Also:Autumn Needle Fly24%Daddy Long Legs23%
Peak emergence windowWeather boost7 food groups active
Peak activity at 18:00 — Caperer (Caperer, Weather boost)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 3 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 2 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · October 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
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2
Small Dark OliveHatch
2
3
3
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Grayling
Hook 14–18 · Fly
in season
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.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Water quality (WFD)
The full read · show the working · for Grayling · confidence 55%
How the 77 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity77 × 12%9.2
Conditions total= 77
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Scieproxy
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2.º Saturday de March → 3.º Sunday de September
- Grayling 3.º Saturday de May → 31 December
France national rule: grayling opens 3rd Saturday of May in all waters. In 2nd category waters, grayling remains open until 31 December. Departmental regulations may impose earlier closing dates. Always check the relevant département's 2026 arrêté préfectoral.
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.
Related guides
Booking & contacts
Authie
Water temperature for Grayling
Ideal11°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Autumn through November prime.
Where
Faster runs in the middle and lower stretches.
Method
Euro-nymphing through the deeper pockets is the daily default; switch to dries on autumn afternoons when sedges and small olives come off. Long fine tippet for the clear water.
Kit
10 ft #3 nymphing rod for the deep pockets; 9 ft #4 for dries. 4 to 5 lb fluoro tippet, 12 ft leader.
Why this works
Good — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Hatch timeline · tomorrowPeak at 18:00
12:00(now) — Autumn Olive
Stage: On emergersApproach: Emerger or dryActivity: 29%
Also:Autumn Needle Fly24%Daddy Long Legs23%
Peak emergence windowWeather boost7 food groups active
Peak activity at 18:00 — Caperer (Caperer, Weather boost)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 3 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 2 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · October 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
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Brown SedgeHatch
2
3
3
3
2
Small SpurwingHatch
2
3
3
3
2
Small Dark OliveHatch
2
3
3
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Grayling
Hook 14–18 · Fly
in season
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.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRAR05
The full read · show the working · for Grayling · confidence 55%
How the 77 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time10 × 13%1.3
Pressure80 × 7%5.6
Insect activity77 × 12%9.2
Conditions total= 77
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Scieproxy
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2.º Saturday de March → 3.º Sunday de September
- Grayling 3.º Saturday de May → 31 December
France national rule: grayling opens 3rd Saturday of May in all waters. In 2nd category waters, grayling remains open until 31 December. Departmental regulations may impose earlier closing dates. Always check the relevant département's 2026 arrêté préfectoral.
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.
Related guides
Booking & contacts