Mayfly in Tokyo

2020/11/25chart,Fly fishing,hatch,Japan,mayfly,Tokyo

For mayfly traditionalists:
According to the statistics shared by my friend who also fish Tokyo's stream, 90% of mayfly diet by trout consist of:

Ephemerellidae - spiny crawler, Madara Kagerou
Heptageniidae - stream mayfly, Hirata Kagerou
Ephemeridae - drake, Mon Kagerou
Baetidae - batis, Ko Kagerou
Leptophlebiidae - blue, Tobiiro Kagerou
Caenidae - caenis, Himeshiro Kagerou

Hatch Chart

HatchSeasonFamilyCommonNamesSizeColourHatchTypeNymphType
March-AprilLeptophlebiidae
トビイロカゲロウ科
Blue Quill22Black, brown, TanTopwaterClinger
March-SeptemberBaetidae
コカゲロウ科
Batis18-22TanTopwaterSwimmer
April-JuneHeptageniidae
ヒラタカゲロウ科
Stream Mayfly14-18Brown, blackUnderwaterClinger
July-AugustCaenidae
ヒメシロカゲロウ科
Caenis26Tan, brownTopwaterCrawler
May-JuneEphemeridae
モンカゲロウ科
Drake10TanTopwaterBurrower
May-SeptemberEphemerellidae
マダラカゲロウ科
Spiny Crawler18Carrot, tan, brownTopwaterCrawler

 

Minority Hatch

Baetiella - twin tail batis, Futaba Ko Kagerou

 

Notes:

Heptageniidaet and baetiella hatch inside water then emerge to surface, so you need floating nymph for slow run/wetfly for fast run. Baetiella always sits with its wing open when being still, so need to cover that with spent pattern.

Caenidae is the micro mayfly you see from time to time around 3mm in size only hatching in slow water with silty bottom which is not very usual in mountain rivers, but I see them selectively eaten in slow pools in village river or stock river.

Ephemerellidae is very common mayfly in Tokyo's mountain stream in June for morning and evening hatch. Daytime is either stream mayfly on size 14 who hatch inside water or terrestrial such as small beetles and ants.

 

Good reference to understand mayfly nymph.

http://museinfo.hitohaku.jp/kawamushi/zukan/kagerou.html

Swimmer, clinger, crawler, and burrower.
How they spread apart in the same water is probably very comparable with crustaceans which I will follow up later.

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