- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR499
Rules at a glance
- Day tickets
- Fly only
Water temperature for Brown Trout
Warm — slow23°C est.ideal 10–16°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
Water at 22.8°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 9 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 3 with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalModerate 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
Grayling seasonSeason
1
2
2
2
1
Brown SedgeHatch
2
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Blue Winged OliveHatch
2
3
3
3
3
2
Mayfly (Green Drake)Hatch
2
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
12-16 · Gammarus Scud
Dead-drift, sub-surface
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
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
The Bienne river at Vaux-les-Saint-Claude, Haut-Jura, near the Gour aux Moines Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity57 × 12%6.8
Limiting factor: Water temperature (22.8°C) is outside Brown Trout's preferred range (10–16°C)= 56
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
- Grayling 3rd Saturday of May → 3rd Sunday of 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
Booking & contacts
Clubs & associations
Bienne
Water temperature for Brown Trout
Warm — slow23°C est.ideal 10–16°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
Water at 22.8°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 9 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 3 with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalModerate 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
Grayling seasonSeason
1
2
2
2
1
Brown SedgeHatch
2
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Blue Winged OliveHatch
2
3
3
3
3
2
Mayfly (Green Drake)Hatch
2
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
12-16 · Gammarus Scud
Dead-drift, sub-surface
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
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
The Bienne river at Vaux-les-Saint-Claude, Haut-Jura, near the Gour aux Moines Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR499
The full read · show the working · for Brown Trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity57 × 12%6.8
Limiting factor: Water temperature (22.8°C) is outside Brown Trout's preferred range (10–16°C)= 56
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
- Grayling 3rd Saturday of May → 3rd Sunday of 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
Booking & contacts
Clubs & associations