Spate · Granite · Co. Down / Mourne Mountains, GB-NIR

River Shimna

The Shimna River running through autumn woodland in Tollymore Forest Park in the Mourne Mountains, County Down, Northern Ireland.

The Shimna is a beautiful mountain spate river flowing from the Mourne Mountains through Tollymore Forest Park to the sea at Newcastle.

Today · Slow going — better windows ahead
Blue-Winged Olive
Forecast · Today
Slow going — better windows ahead
Little in your favour today. Fish the certain lies, or leave it for a better one.
40% projected
Today's fly
Blue-Winged Olive
Blue-Winged Olive
Conditions on the water · Today
Live gauge
Level
Rising
0.18 m
Lifting fast
Water temp15.4°C
ClarityUnfishable
Weather15°C
WindN 44 km/h
Pressure1004 hPa
Rain · recent1.9 mm
Rain · ahead0.8 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Atlantic Salmon
Ideal
15°C est.ideal 10–16°C
0°14°28°
How to fish it · for Atlantic Salmon
When
Morning into early afternoon.
Where
Pool tails, steadier runs, and any water with pace.
Method
Fish a sensible line-and-fly combination for the height and pace of water.
Kit
13 ft #8/9 double-hander in spate, 10 ft #8 single in low water. Floating line plus a fast-sink tip. 12–15 lb fluoro tippet.
Why this works
Fair conditions based on river hydrology and migration patterns.
Likely species
Stoneflies
Caddisflies
Gammarids
Hatch timeline · todayPeak at 12pm

12pm(now) — Heather Fly

Stage: Terrestrials on topApproach: Dry flyActivity: 47%
Also:Reed Smut29%
Peak emergence window4 food groups active

Peak activity at 12pm — Heather Fly (Heather Fly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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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 · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
2
2
2
2
1
March BrownHatch
2
3
2
CapererHatch
2
3
3
2
Heather FlyHatch
2
2
Autumn DunHatch
2
3
2

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

Ranked for today
Atlantic Salmon fly box

Connemara/Mayo low water: a lightly-dressed shrimp on a floating line with sink tip, sized down from 8s in cold spring water to 12s and 14s as summer water warms and clears. Where the current runs faster, a slim tube or hairwing swung through tracks better than a shrimp.

What's coming
Plan ahead
5-day outlook
Other water nearby · 5
River Lagan
18 km
Brown trout
Ballymascanlan River
37 km
Brown trout · Sea trout
River Cusher
37 km
Brown trout
River Lagan — Shaw's Bridge
38 km
Brown trout · Salmon
Castletown River
40 km
Brown trout · Sea trout
Gallery · 2
  1. The Shimna River running through autumn woodland in Tollymore Forest Park in the Mourne Mountains, County Down, Northern Ireland.
    The Shimna River flowing through autumn woodland in Tollymore Forest Park, County Down.
  2. Terrain map of the venue
    Terrain map
About this water

The Shimna is a beautiful mountain spate river flowing from the Mourne Mountains through Tollymore Forest Park to the sea at Newcastle. Clear granite water, fast-draining — rises within hours and drops just as fast. Sea trout from June are the main draw, with small runs of salmon from May. Brown trout are plentiful but small. The Shimna Angling Club manages access. The forest park setting makes this one of the most scenic rivers in Northern Ireland. Fish on the drop after rain — low water means it runs almost dry in summer. Atlantic salmon are managed under DAERA and Loughs Agency conservation byelaws, with mandatory catch-and-release on many waters; check current rules before fishing.

Hatches & food

No venue-specific hatch data yet; as a Mourne upland spate river, expect the sparse, flood-driven mix of stoneflies, small upwings and terrestrials typical of these freestone streams — a general expectation, not an observed hatch.

Sea trout here

Summer-autumn runs, seasonal patterns vary by region

  • Granite
The full read · show the working · for Atlantic Salmon · confidence 75%
How the river scores — hydrology factors
Water heightMedium Ideal0.0
Recent riseNone0.0
Falling after liftNot Applicable0.0
Water temperatureCool To Moderate0.0
Time in seasonOpening Period0.0
ClarityClearing0.0
Hydrology base0.0
Legal gate: Unknown Check Local Rules
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Salmon 1 March → 31 October

Sea trout: Variable seasonal (2026)

Related guides
Atlantic Salmonsalmon tacticsIrish Salmon Rivers Guidefive great salmon fisheriesConnemaraIrish fishing
Casting instructors near here
Booking & contacts