Cage Transfer

In intensively crowded fish farms, small fish are bullied and killed by larger fish, so fish are continually sorted to make sure that faster-growing individuals are moved to the appropriate size grouping. At each sorting, they are netted or pumped out of their tanks and dumped onto a series of bars and grates with varying space gaps to divide them by size and redistribute them into different netted cages or tanks; small fish slip through the small grates, while larger fish fall through the larger gaps. This practice, called "grading," is very stressful and results in painful scrapes, loss of scales, and even death.