Mayfly in 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
[table id=4 /]
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.