Karst · Limestone · Jura / Doubs, FR

Cusancin

A small clear river flowing over a low weir, lined with autumn trees, in the Cusancin valley, France.
Poor · Brown Trout
Pheasant Tail Nymph · 14-18
New ruleReported 17 Jul 2026

Severe drought restrictions (crise) in force

VigiEau lists this venue's surface-water zone (Plateau calcaire jurassien, dépt 25) at crise, under an official préfectoral drought arrêté. Fishing is not itself banned by it, but water levels are low — go gently on stressed fish.

Arrêté préfectoral n°37370 ↗

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date.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
  • Level0.15 mLast reading 3h ago
  • Water temp12.5°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14-18
Upstream
Conditions on the water
Live gauge
Level
Steady
0.15 m
Last reading 3h ago
Water temp12.5°C
ClarityClear
Weather10°C
WindS 12 km/h
Pressure1024 hPa
Rain · recent0.0 mm
Rain · ahead2.1 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Ideal
13°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season. The Cusancin is small intimate karst water — read each lie carefully. Spring olives, summer sedges, autumn small flies.
Where
Pool tails, weeded glides, the cushion behind chalk boulders. The Cusancin is short and small-scale — short casts, careful approach.
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.
Likely species
Stoneflies
Gammarids
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 12 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
Grayling seasonSeason
1
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
SS
Small Streamer
6-10 · Pattern
Swing
Permits & access
Permit required — see local rules.
  • AAPPMA permits required
  • Some beats private; fly-only and no-kill parcours on parts of the river
  • Low limits and short rods recommended.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Reverotte
22 km
0
Brown trout · Grayling
Loue
29 km
0
Brown trout · Grayling · Chub
Doubs (France)
38 km
0
Brown trout · Grayling · Chub
Les piscicultures Côte
26 km
Rainbow trout
Dessoubre
34 km
Brown trout · Grayling
Gallery · 2
  1. A small clear river flowing over a low weir, lined with autumn trees, in the Cusancin valley, France.
    cusancin
  2. Terrain map of the venue
    Terrain map
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 FRDR11271 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRDR11271

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 activity61 × 12%7.3
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
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 2.º Saturday de March → 3.º Sunday de September
  • Grayling 3.º Saturday de May → 3.º Sunday de September

    France national rule: grayling opens 3rd Saturday of May in all waters. In 1st category (salmonid) rivers, grayling closes with the trout season on the 3rd Sunday of September. Departmental regulations may impose additional restrictions. Always check the relevant département's 2026 arrêté préfectoral.

Related guides
Grayling Playbookgrayling tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts