The old school pictures are of "the stilt fisherman of Sri Lanka".
The new school of Pyramid lake fisherman.
I would only be guessing as to the use of the plastic bottles and will leave that answer to the guys who fish Pyramid. They have been fishing this way for some time and I would be interested to learn of their technique and reasons for the ladders.
For further incite into the two oddities, try a google search of the images for "stilt fisherman" and " Pyramid Lake". It's interesting.
I first learned of the stilt fisherman watching the GlobeTreker on a local PBS TV episode, and in my own weird way connected the Pyramid lake ladder fishers with them.
Anybody wants to jump in with some info, go for it.
"As far down the river as he could see, the trout were rising, making circles on the surface of the water, as though it were starting to rain."- E.H., The Big Two Hearted River