Freestone · Volcanic · Hokkaido

Akan River

Akan Riv 1
Good · Rainbow Trout
Foam beetle / hopper · 10-14
Goodlive now
A proper day on the water
Low and clear — careful approach country. Stay small, stay accurate.
75% confidence
What moved it
  • LevelLight rain recentlyNo gauge reading
  • Water temp17.7°C
  • ClarityClear
Today's fly
Foam beetle / hopper
Foam beetle / hopper10-14
Proven pattern for this period
Conditions on the water
Estimate
Level
Light rain recently
No gauge reading
Water temp17.7°C
ClarityClear
Weather19°C
WindSE 5 km/h
Pressure1015 hPa
Rain · recent7.3 mm
Rain · ahead12.7 mm

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

Water temperature for Rainbow Trout
Ideal
18°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow 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 right today, though time of day could be better.
Hatch timeline · todayPeak at 1pm

Hatch predictions

Today's headline hatch shown — see all 12 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 2 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
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Stenopsyche CaddisHatch
2
3
3
2
Cicada (Semi)Hatch
2
2
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2

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

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Managed C&R/charge zone near the lake outflow — confirm payment, permitted reach and hook rules.
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. Akan Riv 1
    River draining Lake Akan.
  2. Terrain map of the venue
    Terrain map
Conservation note

Rainbow trout and white-spotted char (amemasu). Lead with the managed catch-and-release upper reach.

The full read · show the working · for Rainbow Trout · confidence 75%
How the 79 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time45 × 13%5.9
Pressure75 × 7%5.3
Insect activity62 × 12%7.4
Conditions total= 80
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Char spring → late autumn

    Hokkaido is largely open-access for inland trout/char, with managed/charged zones the exception (e.g. the Akan C&R water). Verify the exact reach. Species surfaced in prose only. Legal status: guidance_not_permission.

Related guides
Euro Nymphingsubsurface methods
Booking & contacts