One section of the Great Wall of China runs along the peaks of the Yanshan mountains to the north of Beijing. In one of the ravines running down the southern side of the mountains, immediately below the wall, there is a fish farm which uses the pure mountain streams to keep the water in its tiers of open-air fish tanks clean and fresh.
This fish hatchery is a very slick operation, started by a couple of Canadians some years ago, and aiming to provide fresh salmon for the local market and for tourists visiting the Great Wall (when I say tourists I do not mean western visitors to China, I mean Chinese people who are exploring their own country), and there are thousands of visitors most days.
There is a cluster of buildings near the parking area, which includes several labs where the fish eggs are collected fertilised, hatched and incubated. The small fry are moved from indoor tank to tank as they grow until they are large enough to go to the outdoor area. Then the young fish move up the mountain-side from tank to tank as they increase in size/age. Eventually they end up in pools at the upper-most level, where some people ‘fish’ for them with a crude rod and line. Most fish in the pools are salmon, but there are also golden carp which are a very popular fish with Chinese diners.
There is another chap on duty who kills the fish by whacking it hard with a metal cudgel and then weighing it and charging accordingly. Few people take the fresh fish home with them. The usual thing is to hand the fish over to the staff at one of the roadside diners where the fish is filleted, soaked in various sauces and then grilled over hot coals. Ten minutes at the most between the fish being netted and sitting down to eat it!