Spate · Peat · Outer Hebrides / Lewis

Grimersta River & Loch System

Grimersta River & Loch System terrain map
Terrain map

Scotland's most famous island salmon fishery — a short, fast spate river draining a chain of lochs on the west side of Lewis.

Species

Slow going — better windows ahead

Low and clear — careful approach country. Fish on a shallow rise are spooked — choose your hour.

50% confidence in this read
Water temperature for atlantic salmon
Cool — slow
5°C est.ideal 10–14°C
0°14°28°
Why this score · for atlantic salmon
  • Temperature830% weight
  • Flow6025% weight
  • Clarity8520% weight
  • Feeding Time1015% weight
  • Pressure8510% weight
Conditions
Level
0.31 m
Water temp
5.1°C
Estimated
Clarity
Slightly coloured
Air temp
6°C
Wind
S 8 km/h
Light breeze
Pressure
1001 hPa
Rain · 48h
0.0 mm
No meaningful rain
Rain · ahead
6.0 mm
Light rain · next 48h

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

How to fish it · for atlantic salmon
When
All day — lough fishing is best in a good wave. Early morning and evening can produce in calm conditions.
Where
Work the drift lanes from the upwind shore across the productive zones. Cover bay edges, underwater reefs, and any areas where the bottom shoals.
Method
Fish a sensible line-and-fly combination for the height and pace of water.
Kit
10 ft #7/8 single-hander, floating line, 10–12 lb fluoro leader. Boat seat and waterproofs for the drift.
Why this works
Very poor conditions. Clarity is favourable (85), Temperature is weakest (8).
Through the year
0–3 scale · May highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
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.

Permits & access
Permit required — see local rules.
  • Premium managed fishery — advance booking through Grimersta Estate
  • Very limited availability
  • Fly only.
Directions
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About this water

Scotland's most famous island salmon fishery — a short, fast spate river draining a chain of lochs on the west side of Lewis. The Grimersta is extraordinary: in a good spate it can produce salmon catches that rival any river in Scotland, despite being barely a mile long. The system's magic lies in its chain of lochs which act as holding pools, and the short river which fish run through in hours rather than days after rain. Sea trout also run the system in good numbers. The fishing is managed as a premium let and commands high prices, but when it fires after a summer spate, there is nothing else quite like it in Scottish salmon fishing.

  • Loch
  • Peat
Seasons & zones
  • Salmon11 February → 31 October

Sea trout: Variable seasonal (2026) — Grimersta — the most celebrated sea trout system in the British Isles historically. Lewis loch chain with a legendary record for very large sea trout. Stocks have collapsed under sea-lice pressure from west-coast salmon farms; catches are a fraction of their 1970s–80s peak. Still worth fishing carefully when conditions align, but the days of double-figure fish in numbers are gone. Catch-and-release mandatory under contemporary estate management.

Other water nearby · 5
Booking & contacts