Spate · Granite · Brittany / Finistère

Elorn

Fast white water pouring over a weir on the Elorn river at Landerneau, with ducks resting on the flow, in Finistere, Brittany, France.
Contributor photo

L'Elorn, Landerneau, Finistere

Olive Titus - CC BY 2.0

The Elorn runs fifty-six kilometres across the granite of western Finistère and holds the most productive Atlantic salmon population in the Rade de Brest system.

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.
80% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp21.4°C
  • ClarityClear
Today’s fly
CDC Emerger
CDC Emerger16-18
Dead-drift
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp21.4°C
ClarityClear
Weather17°C
WindNE 12 km/h
Pressure1016 hPa
Rain · recent1.8 mm
Rain · ahead18.4 mm

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

Water temperature for brown trout
Warm — slow
21°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; spate-driven on falling water.
Where
Pool tails and pocket water through the Finistère valley. The Elorn was once Brittany's salmon flagship; the brown-trout fishing remains.
Method
Upstream dry to risers; dry-dropper through the riffles. Breton spate freestone — fish 12 to 24 hours after rain on the drop. Long leader, fine tippet.
Kit
9 ft #4 — Breton spate freestone. Floating line, 12 ft leader to 4 lb fluoro. Studded boots.
Why this works
⚠️ Water at 21.4°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots. Otherwise very poor — water clarity is in the right range.
Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

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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
Salmon runRun
1
2
2
2
1
Trout seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Yellow SallyHatch
2
3
2

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 21°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Fast white water pouring over a weir on the Elorn river at Landerneau, with ducks resting on the flow, in Finistere, Brittany, France.
    L'Elorn, Landerneau, Finistere
  2. Terrain map of the venue
    Terrain map
About this water

The Elorn runs fifty-six kilometres across the granite of western Finistère and holds the most productive Atlantic salmon population in the Rade de Brest system. It is spate water, and it must be fished as such: wait for the lift, fish the drop. Spring is the best of it — March through May, when the runs concentrate on the rising water after Breton rainfall. Tube flies of an inch and a half in coloured water, reducing to doubles and standard tied flies as the water clears. The best pools lie between Sizun and La Roche-Maurice, on classical Breton holding water: clean gravel in the tails, deeper lies against the bedrock walls of the central pools. Sea trout run with the salmon and take the same flies in daylight, which distinguishes Brittany from the Cumbrian and Welsh waters where the sea trout are strictly a night quarry. Resident brown trout are wild and managed as a patrimonial population. Check the current AAPPMA arrêté before fishing — the salmon season varies year on year and the quota is usually tight.

Under the surface

The Elorn rises a stone's throw from the moorland of the Monts d'Arree and runs some forty-two kilometres across north Finistere — through Sizun, Landivisiau and Landerneau — to a long estuary opening into the Rade de Brest. It is a modest Breton river of clear, cool, acidic water off the granite uplands, fed by sixteen tributaries and by the Drennec reservoir near its source, which steadies the upper flow as a tailwater below the dam. For all its reputation it rarely exceeds ten metres in width, a small river of easy pools and gentle gradient running through wooded and farmed country. It holds a stable run of Atlantic salmon — a couple of hundred fish in recent years — and beautiful trout that share the lower water. The character is intimate, slow-profiled freestone where the salmon lies are easy to read. Wading is steady on firm rock and gravel.

Wading: Steady footing on a small clear river

  • Granite
  • Partly confined
  • Pool riffle
Water quality (WFD)
  • EcologyModerate
  • ChemicalUnknown

WFD classification · FRGR0066C

The full read · show the working · for brown trout · confidence 80%
How the 19 is built — score × weight = contribution
Temperature11 × 28%3.1
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity35 × 12%4.2
Limiting factor: Water temperature (21.4°C) is outside Brown Trout's preferred range (10–16°C)= 55
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
  • Salmon1 March → 31 July
  • Trout2nd Saturday of March → 3rd Sunday of September

Salmon: Banned (2026) — Brittany 2026 order bans Atlantic salmon and sea trout on all Breton rivers.

Sea trout: Banned (2026) — Brittany 2026 order bans Atlantic salmon and sea trout on all Breton rivers.

Related guides
Booking & contacts