These huge fishing contraptions are called Cheena Vala, or Chinese fishing nets. Made of 30-foot bamboo poles, they came into use in India somewhere around 1350 to 1450 AD. Deputy dog takes a closer look at these marvels of engineering, with videos of the nets in action. http://deputy-dog.com/2008/10/indias-ingenious-fishing-contraptions.html
(image credit: ezee 123 aka Anoop Negi)
But they catch fish in a huge river.