Chalk · Pas-de-Calais / Fruges–Aire-sur-la-Lys, FR

Lys (headwaters)

Lys (headwaters) terrain map
Poor · Brown Trout
Parachute Adams · 14-16
New ruleReported 15 Aug 2026

Severe drought restrictions (alerte renforcée) — angling may be restricted

VigiEau lists this venue's surface-water zone (Bassin versant de la Lys, dépt 62) at alerte renforcée, under an official préfectoral drought arrêté. The decree allows angling to be restricted in this zone; check the arrêté and local notices before fishing.

Arrêté préfectoral n°37723 ↗

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • LevelProxyvia Scie
  • Water temp14.5°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams14-16
Upstream dry
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Scie
Water temp14.5°C
ClarityClear
Weather16°C
WindSW 20 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead1.0 mm

No gauge on this water — conditions are inferred from Scie. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Ideal
15°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Likely species
Stoneflies
Gammarids
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 10 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 as a supporter.

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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
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 · Brown Trout
Permits & access
Permit required — see local rules.
  • AAPPMA Ternoise / Haute Lys
  • Parcours courts
  • Ne pas pêcher la Lys canalisée en aval d'Aire — elle n'abrite pas de truites significatives.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Canche
12 km
0
Brown trout · Grayling · Sea trout
Ternoise
21 km
0
Brown trout
Course
26 km
0
Brown trout
Pisciculture de Wail
19 km
Rainbow trout
Pisciculture de Monchel
24 km
Rainbow trout
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown
What this classification means

WFD ecological status Good → Moderate corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRAR36 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRAR36

The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity67 × 12%8.0
Conditions total= 84
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
Apple MapsGoogle Maps
Seasons & zones
  • Trout 2e Saturday de March → 3e Sunday de September
Related guides
Chalkstream Playbookchalk stream tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts