Chalk · Pas-de-Calais / Boulogne-sur-Mer, FR

Liane

Liane boulogne62

The Liane runs about forty kilometres from its source near Quesques down through Samer to Boulogne-sur-Mer, a short coastal chalk stream that most fly anglers have never heard of.

Poor · Sea Trout
Black & Silver Tube · 1–2 inch
Closed season
Out of season. File this water for the right month.
Closed — confidence not applicable today.
What moved it
  • LevelProxyvia Scie
  • Water temp10.1°C
  • ClarityClear
Today's fly
BS
Black & Silver Tube1–2 inch
In deep pools and dark water, silhouette and contrast do the work colour cannot. A fly that reads as black against depth is enough. Fish it broadside, hold the swing, let it hang at the dangle — that is when the best fish take.
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Scie
Water temp10.1°C
ClarityClear
Weather-1°C
WindSE 9 km/h
Pressure1019 hPa
Rain · recent0.1 mm
Rain · ahead10.1 mm

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

Water temperature for Sea Trout
Ideal
10°C est.ideal 8–15°C
0°14°28°
How to fish it · for Sea Trout
When
Sea trout present on the Liane — small-scale fishery, condition-dependent. Confirm current AAPPMA rules before targeting.
Where
Lower Liane pool tails through to the Boulogne tidal limit.
Method
Across-and-down on a floating line with size 10 to 12 wets — Steer's Head, Stoat's Tail, soft-hackle emerger. Steady swing, never hurry. Carte de pêche with timbre migrateur required.
Kit
10 ft #6/7, floating line, 8 lb fluoro tippet. Spare leader on a wrist spool.
Likely species
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

Start free trial

14-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 trial

14-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 · November 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
Sea Trout fly box

Classic French chalkstream fishing. Gin-clear, weed-rich, slow to moderate flow. Dry fly and sight nymphing dominate. Stronger sedge hatches than English equivalents. French tradition favours flush-sitting dries (comparaduns, CDC patterns) and upstream presentation.

BS
Black & Silver TubeTop
1–2 inch · Tube
In deep pools and dark water, silhouette and contrast do the work colour cannot. A fly that reads as black against depth is enough. Fish it broadside, hold the swing, let it hang at the dangle — that is when the best fish take.
Medicine Fly
Medicine Fly
8–12 · Streamer
Slim and mobile — fished sunk through the pool when surface work is not producing. Consistently takes fish that will not come to the surface.
Permits & access
Permit required — see local rules.
  • AAPPMA access
  • Sea trout fishing concentrated on lower meadows below Hesdin-l'Abbé — verify permit coverage of the tidal sections.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
  1. Liane boulogne62
  2. Terrain map of the venue
    Terrain map
About this water

The upper half is proper brown trout water — clear, watercressed, rich with olives and sedges — and the lower half, below the tidal limit, gets a genuine sea trout run in late summer and autumn. It's not a famous river and it's not a large one, but it has the things that matter: stable water temperatures, proper fly life, wild fish. The AAPPMA beats around Hesdin-l'Abbé are good value for a day's fishing, and the sea trout fishing in the lower meadows in September, when the water drops and the fish come in on the bigger tides, is the kind of thing you remember.

Hatches & food

In chalk-spring and karst trout systems, generally stable temperatures broaden olive and other mayfly activity from early spring into autumn, with strong evening caddis, steady subsurface scuds and buzzers where clear groundwater and weedbeds develop, and terrestrials from meadow and woodland banks rounding out the food calendar, depending on how fast each river drops and clears after rain.

  • Chalk
Water quality (WFD)
  • Ecology: Moderate
  • Chemical: Unknown

WFD classification · FRAR30

Why this score · for Sea Trout
  • Temperature10028% weight
  • Flow8022% weight
  • Clarity8518% weight
  • Feeding Time10013% weight
  • Pressure857% weight
  • Insect activity6112% weight
Directions
Seasons & zones
  • Trout 2nd Saturday of March → 3rd Sunday of September

Sea trout: Variable seasonal (2026)

Related guides
Casting instructors near here
Booking & contacts
At a glance

Liane is a chalk stream in Pas-de-Calais / Boulogne-sur-Mer, France. The catchment geology is recorded as chalk, and the water sits at about 80 m above sea level. The river is described as roughly 38 km long. Species listed for this water: brown trout and sea trout. The trout season is recorded as running from 2nd Saturday of March to 3rd Sunday of September. Best window recorded for anglers: April–June (trout); August–September (sea trout). Core methods listed: Dry fly; nymphing; wet fly (sea trout). Its Water Framework Directive ecological status is recorded as moderate. Access is recorded as day tickets through the local AAPPMA (angling association). Nearby waters in our listings include Course at 18 km, Lys (headwaters) at 33 km and Canche at 40 km.