Freestone · Granite · Lozère

Tarn (Upper)

Aerial view of the Tarn river winding through the deep limestone Gorges du Tarn, with a village and wooded slopes visible.
Contributor photo

Gorges du Tarn, France

Philip Larson - CC BY-SA 2.0

The upper Tarn rises on the Cévennes flank of Mont Lozère and runs south-west through granite and schist country before the famous limestone gorges take over further down.

Poor · Brown Trout
CDC Emerger · 16-18
Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
90% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp23.0°C
  • ClarityClear
Today’s fly
CDC Emerger
CDC Emerger16-18
Dead-drift
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp23.0°C
ClarityClear
Weather30°C
WindSW 14 km/h
Pressure1017 hPa
Rain · recent0.0 mm
Rain · ahead1.4 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for brown trout
Warm — slow
23°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
Pool tails and pocket water through the Lozère gorge stretches. Cévennes freestone — clear water, intimate scale.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet. Move slowly, cast accurately.
Kit
9 ft #4 — French freestone default. Floating line, 12 ft leader to 4 to 5 lb fluoro. Studded boots.
Why this works
⛔ Water at 23°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

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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
Large Dark OliveHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1
Autumn OliveHatch
1
2
1
GrannomHatch
1
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.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Aerial view of the Tarn river winding through the deep limestone Gorges du Tarn, with a village and wooded slopes visible.
    Gorges du Tarn, France
  2. Terrain map of the venue
    Terrain map
About this water

The upper Tarn rises on the Cévennes flank of Mont Lozère and runs south-west through granite and schist country before the famous limestone gorges take over further down. What most tourists think of as the Gorges du Tarn is the postcard section below Florac; the fishing is further up, in the headwater country above Les Vignes where wild brown trout and grayling share fast runs with the occasional deep holding pool. The grayling here are the real draw — good numbers, willing feeders, and educated enough to make you pay attention. Work upstream with a small olive or baetis imitation in spring, move to caddis in June, keep a brace of pheasant-tail nymphs for when nothing is showing. The gauge runs quickly after rainfall — which is often, because this is Cévennes weather — so plan with the trend in mind. A classic southern river in a landscape that will distract you from the fishing, which is its own kind of problem.

  • Granite
Water quality (WFD)
  • EcologyModerate
  • ChemicalUnknown
What this classification means

WFD ecological status Good → Moderate corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody FRFR305 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · FRFR305

The full read · show the working · for brown trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity47 × 12%5.6
Limiting factor: Water temperature (23°C) is outside Brown Trout's preferred range (10–16°C)= 50
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
  • Trout2nd Saturday of March → 3rd Sunday of September
  • Grayling3rd 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
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