A few lives ago, I worked on a factory trawler that caught, processed, froze and boxed pollock around the Aleutian islands and the Sea of Okhotsk.
The greenhorns worked the candling tables, which looked exactly like the conveyors pictured but were only 10 feet long and were lit from within. A table was fed continuous heaps of fish slop from the fillet machines and the candler's job was to straighten each fillet and examine it for parasites, bones, etc.
The tables moved pretty fast, the fillets were colder than ice, and in order to feel the bones we wore thin medical gloves. While shifts were only 6 hours, we worked 2-3 shifts per day.
The constant hand movement was the worst part. At age 21, I'd wake up unable to move my fingers. After a shift of staring at the conveyor, your eyes would skip about as they do when you spin yourself around quickly and suddenly stop.
That was terrible work, and the stuff above looks only slightly better... they have stools.
...aaannndd the Starbucks down the street just got a Clover