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

Lys (headwaters)

Lys (headwaters) terrain map
Good · Brown Trout
Spent Spinner · 16-20
New ruleReported 15 Aug 2026

Severe drought restrictions (alerte renforcée) in force

A préfectoral drought order places this catchment's surface water at alerte renforcée, the second-highest of France's four restriction tiers. Fishing itself is not named in the order, but flows are low and water-use restrictions are in force. Zone: Bassin versant de la Lys (dépt 62).

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Temporary notices from official orders and recent fishery reports — they clear automatically once out of date.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.

Goodlive now
A proper day on the water
Low and clear — careful approach country. Stay small, stay accurate.
75% confidence
What moved it
  • LevelProxyvia Scie
  • Water temp16.6°C
  • ClarityClear
Today's fly
Spent Spinner
Spent Spinner16-20
Upstream dry
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Scie
Water temp16.6°C
ClarityClear
Weather16°C
WindSW 23 km/h
Pressure1011 hPa
Rain · recent8.1 mm
Rain · ahead24.1 mm

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

Water temperature for Brown Trout
Warm — slow
17°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.
Why this works
Good — water clarity is right today, though time of day could be better.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 11 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds with Pro.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 with Pro.

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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 · August 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
Brown Trout fly box
Permits & access
Permit required — see local rules.
  • AAPPMA Ternoise / Upper Lys
  • Short beats
  • Do NOT fish the canalised Lys below Aire — it holds no trout of consequence.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Canche
12 km
Brown trout · Grayling · Sea trout
Pisciculture de Wail
19 km
Rainbow trout
Ternoise
21 km
Brown trout
Pisciculture de Monchel
24 km
Rainbow trout
Course
26 km
Brown 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 75%
How the 76 is built — score × weight = contribution
Temperature79 × 28%22.1
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 76
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 2nd Saturday of March → 3rd Sunday of September
Related guides
Chalkstream Playbookchalk stream tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts