Karst · Limestone · Jura / Haut-Jura (Saint-Claude)

Bienne

Bienne terrain map
Terrain map

The Bienne rises high on the Jura plateau above Morez and runs one hundred kilometres through limestone gorges, meadows, and finally to the Ain with the composure of water that knows precisely where it belongs.

Good · Brown Trout
CDC Emerger · 16-20
Goodlive now
A proper day on the water
Low and clear — careful approach country. Stay small, stay accurate.
90% confidence
What moved it
  • Flow1.2 m³/sLast reading 6h ago
  • Water temp17.4°C
  • ClarityClear
Today’s fly
CDC Emerger
CDC Emerger16-20
Dead-drift
Conditions on the water
Live gauge
Flow
Steady
1.2 m³/s
Last reading 6h ago
Water temp17.4°C
ClarityClear
Weather23°C
WindE 8 km/h
Pressure1020 hPa
Rain · recent1.4 mm
Rain · ahead4.8 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for brown trout
Warm — slow
17°C est.ideal 1016°C
0°14°28°
How to fish it · for brown trout
When
Through the open trout season. Spring olives April through May; sedges through summer evenings; small dark flies into autumn close.
Where
Karst water through the Haut-Jura valley around Saint-Claude. Pool tails and the cushion behind limestone boulders.
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.
Why this works
Good — conditions well-balanced, with water clarity particularly in your favour.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 10 active hatches hour by hour with Pro.

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Evidence
Survey-backed · regionalModerate confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · July 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
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1

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 permits required
  • Fly-only and no-kill parcours on several marked stretches
  • Check the FDAAPPMA du Jura maps for closed zones.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
About this water

The Bienne rises high on the Jura plateau above Morez and runs one hundred kilometres through limestone gorges, meadows, and finally to the Ain with the composure of water that knows precisely where it belongs. The upper reaches are pocket water — narrow, cold, quick-flowing — where wild Jura trout respond to anything cast in front of them without ceremony. The middle reaches around Saint-Claude open into glides and riffles where the fishing requires the restraint the water itself demands: fine tippets, small dries worked to genuinely rising fish, and an absolute refusal to hurry. The grayling below Saint-Claude hold in numbers that astonish, particularly in September when the season turns toward their favour. This is the river where French competition nymphing found its grammar — where team tactics and long leaders and Perdigon techniques were refined into precision. If you want to understand why European nymphing strategies took hold, spend a day watching the locals work this water. Autumn and spring offer the cleanest fishing; summer thermal buffering fades as the karst dries and the plateau warms. This is a river for patient anglers who understand that excellence, once found, is worth the discipline required to meet it.

  • Limestone
Water quality (WFD)
  • EcologyGood
  • ChemicalUnknown

WFD classification · FRDR499

The full read · show the working · for brown trout · confidence 90%
How the 78 is built — score × weight = contribution
Temperature68 × 28%19.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Conditions total= 78
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
Directions
Seasons & zones
  • Trout2nd Saturday of March → 3rd Sunday of September
  • Grayling3rd Saturday of May → 3rd Sunday of September
Related guides
Booking & contacts