Spate · Mixed · Cantabria (Guriezo / Castro-Urdiales), ES

Río Agüera

An eastern Cantabrian coastal river rising in the Montes de Ordunte and falling north through Guriezo to the Bay of Biscay between Castro-Urdiales and Laredo.

Species

A proper day on the water

River steady at a fishable height. A proper day for it.

75% confidence in this read
Water temperature for brown trout
Ideal
11°C est.ideal 10–16°C
0°14°28°
Why this score · for brown trout
  • Temperature10028% weight
  • Flow4022% weight
  • Clarity9518% weight
  • Feeding Time5013% weight
  • Pressure807% weight
  • Insect activity4012% weight
Conditions
Level
0.66 m
Water temp
10.5°C
Estimated
Clarity
Clear
Air temp
14°C
Wind
S 8 km/h
Light breeze
Pressure
1016 hPa
Rain · 48h
0.0 mm
No meaningful rain
Rain · ahead
6.4 mm
Light rain · next 48h

Live readings — water temperature is an estimate where the gauge does not record it.

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
Good — water temperature is working for you, but insect activity is the limiting factor today.
Through the year
0–3 scale · June highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
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.

Permits & access
Permit required — see local rules.
  • Cantabrian licencia de pesca required
  • Eastern coastal basin — check Trasmiera annex for any sea-trout-specific rules.
Directions
Apple MapsGoogle Maps
About this water

An eastern Cantabrian coastal river rising in the Montes de Ordunte and falling north through Guriezo to the Bay of Biscay between Castro-Urdiales and Laredo. The Agüera is best known as a small sea-trout river in modern terms — wild brown trout in the middle reaches, with a fragile reo (sea-trout) population running into the lower river in summer. Mixed limestone-and-sandstone geology gives reasonable clarity but the river drops back quickly after rain. Best fished in May and June for trout, with sea trout interest from July onwards after summer rain.

  • Mixed
Seasons & zones
  • Sea troutFollows Trout
  • Troutthird Sunday of March → 31 July

Sea trout: Variable seasonal (2026)

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