A river scene in Hoi An.  Barely discernable in the center on the far side are fishermen with a “lift-net”.  They set square nets that sink to the bottom on pole-rigs; they then wait a bit and lift the nets with the poles very rapidly and see what they bring up.

There are bigger versions of these lift-net-rigs on the lakes which are ingenious creations of leverage and determined will to make do with what is at hand.