Concrete walls killed the small river.
There were no spawning place in the riverbed.
3面護岸の川は、魚の産卵場所がなく、天然魚は激減、そこに養殖魚を放流すると、生態系が狂って天然魚はさらに減って、放流しないと何も居ない。
まさしく負のスパイラルですね。

SL6 Black Spey Hooks

DU3 Limerick Spinner Hooks

SL4 Single Bartleet Hooks

XD1 Tube Fly Double Hooks

DD2 Flat Perfect Hooks

DD1 Black Terrestrial Hooks

TD4 Old Limerick Wet Hooks

DU1 Silver May Hooks

MU1 Flat Midge Hooks

LD3 Long Limerick Hooks

TD2 Summer Sproat Hooks

XS1 Tube Single Silver Hooks

TD6 Siver Sedge Hooks

SL5 Black Spey Hooks

DU3 Limerick Spinner Hooks