Spate · Granite · Brittany / South Finistère, FR

Isole

Photo of Isole
Marginal · Brown Trout
Pheasant Tail Nymph · 14-18
New ruleReported 7 Aug 2026

Severe drought restrictions (crise) in force

A préfectoral drought order places this catchment's surface water at crise, the highest of France's four restriction tiers. Fishing itself is not named in the order, but flows are low and water-use restrictions are in force. Zone: SUD CORNOUAILLE - ISOLE (dépt 29).

Arrêté préfectoral n°37652

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • Level0.55 mLast reading 3h ago
  • Water temp18.3°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14-18
Upstream
Conditions on the water
Live gauge
Level
Steady
0.55 m
Last reading 3h ago
Water temp18.3°C
ClarityClear
Weather18°C
WindS 17 km/h
Pressure1011 hPa
Rain · recent0.0 mm
Rain · ahead5.9 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
Warm — slow
18°C est.ideal 1016°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 18.3°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6am

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds with Pro.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 with Pro.

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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 · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Large Brook DunHatch
2
3
2
Large StoneflyHatch
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.
  • Permis AAPPMA.
What's coming
Plan ahead
5-day outlook
Water here around 18°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Photo of Isole
    Isole — image via Wikipedia (Isole)
  2. Terrain map of the venue
    Terrain map
Water quality (WFD)
  • EcologyGood
  • ChemicalUnknown

WFD classification · FRGR0091

The full read · show the working · for Brown Trout · confidence 80%
How the 38 is built — score × weight = contribution
Temperature36 × 28%10.1
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity51 × 12%6.1
Conditions total= 62
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 March3rd 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