Freestone · Granite · Hautes-Pyrénées / Cauterets

Gave du Marcadau

A rocky mountain stream, the Gave du Marcadau, running through a green valley with Pyrenean peaks in the background near Cauterets.

Tributary of the Gave de Pau at Cauterets, flowing through a granite valley where the light seems to sharpen the mountains.

Prime · Brown Trout
Small Perdigón · 16-20
Primelive now
About as good as it gets
Low and clear — careful approach country. Take your time — read the water before you cast.
90% confidence
What moved it
  • LevelLight rain recentlyNo gauge reading
  • Water temp13.8°C
  • ClarityClear
Today's fly
Small Perdigón
Small Perdigón16-20
Euro-nymph
Conditions on the water
Estimate
Level
Light rain recently
No gauge reading
Water temp13.8°C
ClarityClear
Weather13°C
WindS 7 km/h
Pressure1025 hPa
Rain · recent3.6 mm
Rain · ahead10.0 mm

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

Water temperature for Brown Trout
Ideal
14°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Late spring through early autumn — high alpine tributary, fishes only when snow has cleared. June through September realistically.
Where
Pocket water through the Cauterets valley. High Pyrenean character — clear cold water, intimate scale.
Method
Short upstream dry-dropper to wild fish in pocket water. The Marcadau is small mountain water — short casts, quiet wading.
Kit
8 ft #3 — small alpine stream. Floating line, 9 to 12 ft leader to 4 lb fluoro. Studded boots.
Why this works
Excellent — water temperature is right today, though insect activity could be better.
Likely species
Mayflies
  • Blue-winged oliveMost likely
    #16–18 · Dun
    Duns are up; a sherry spinner fall may follow.
  • Green drakeAlso possibleLower confidence
    #8–10 · Dun
    Duns are up — the Spent Gnat spinners fall at dusk.
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 4 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 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 · 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
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Brown Trout fly box

French nymph-first water. Fast current, technical presentation, weighted nymphs and emergers, with dry flies when fish rise.

Permits & access
Permit required — see local rules.
  • AAPPMA permits
  • Fly-only sections common in Pyrenees.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
La Truite des Pyrénées
18 km
Rainbow trout · Brown trout
Lac des Especières
28 km
Brown trout
Cinca
41 km
Brown trout
Ara
43 km
Brown trout
Gave d'Estaubé
47 km
Brown trout · Grayling
Gallery · 2
  1. A rocky mountain stream, the Gave du Marcadau, running through a green valley with Pyrenean peaks in the background near Cauterets.
    Cauterets, vallee du Marcadau
  2. Terrain map of the venue
    Terrain map
About this water

Tributary of the Gave de Pau at Cauterets, flowing through a granite valley where the light seems to sharpen the mountains. ~1300 m designated no-kill fly-only (barbless hooks required). Wild brown trout in pristine conditions. High altitude, short season, responsive to snowmelt. Best from June when water clears.

Hatches & food

In the Pyrenean gaves and headwater torrents, resident brown trout move from early-season olives and March browns into strong spring and early-summer stonefly activity, then a long spell of evening caddis and small buzzers, with terrestrials most relevant on wooded lower gaves and much less important high above the tree line.

  • Granite
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · FRFRR245_3

The full read · show the working · for Brown Trout · confidence 90%
How the 84 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity52 × 12%6.2
Conditions total= 84
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Apple MapsGoogle Maps
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
Grayling Playbookgrayling tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
Booking & contacts